B.—Teleostei.—Plectognathi.

Fig.101.—Synanceia brachio, var.verrucosa. (After Savtschenko.)

The spiny rays of the dorsal fin ofSynanceiaare sharp-pointed, stout in the middle, and provided on each side with a small canal hollowed out in the thickness of the spine. Towards the middle of the latter there is attached a little double sac, or kind of closed pouch, which, on being compressed, allows the venom to escape in a thin jet which flows into the grooves of the spine. The expulsion of the venom is therefore not a voluntary act on the part of the fish; in order that it shall take place, pressure must be applied to the sacs in which it is contained.

This venom, when extracted from the glands, is limpid, bluish, and slightly acid. When introduced into the tissues, it produces very acute local pain, which extends throughout the affected limb. Thepain is excruciating, and sufferers have been observed to become actually delirious, striking and biting those around them, throwing themselves from side to side, and beseeching that the limb should be cut off; some of them have amputated the injured part themselves.

This condition is accompanied by considerable anxiety, and by attacks of leipothymia and sometimes of syncope. In some cases syncope has been followed by death; in others serious phlegmons, complicated by septicæmia, supervene. The inoculated spot becomes bluish, and then sphacelates over a larger or smaller area. These gangrenous wounds heal very slowly, more especially since they are usually produced on the sole of the foot (Bottard).

A single drop of the venom is sufficient to kill frogs in about three hours.

Fig.102.—Cottus scorpius(Sea Scorpion). (After Savtschenko.)

The genusCottus, which also belongs to the familyTriglidæ, includes some forty venomous species found in the seas of the northern hemisphere, in Europe, Asia, and America.

In France the species ofCottusare generally calledchabots(bullheads or miller’s thumbs),chaboisseaux(sea-scorpions), orcaramassons. They are abundant on the coast of Normandy, and some of them (river bullheads) live in fresh water; they do not exceed 25 cm. in length. They have a liking for holesin rocks, and fishermen are afraid of being stung by them (fig. 102).

Their poison-apparatus resembles that of the Weevers, but is less developed. It is situated in the culs-de-sac formed by the opercular spines. The culs-de-sac are lined with cells which produce a toxic secretion only during the spawning season, from November to the end of January. This fact explains how it is that the species ofCottusare declared by certain fishermen to be very venomous, while others say that they are absolutely harmless.

The generaScorpæna,PteroisandPeloralso belong to the same group.

Fig.103.—Scorpæna grandicornis(Caribbean Sea). (After Savtschenko.)

InScorpænathe body is clothed with scales, and the head is large, slightly compressed, armed with spines, and has a bare pit behind; the single dorsal fin is provided with eleven spiny rays, and there are seven branchiostegal rays.Scorpæna grandicornis(fig. 103), found in the Caribbean Sea, is from 30 to 50 cm. in length, and has the back red and the eyes and belly yellow;Scorpæna diabolus(fig. 104), which occurs in the Indian Oceanand Tropical Pacific, is red and brown, obliquely striped with white and brown; a third species,Scorpæna porcus(Scorpène truie), of smaller size, is met with in the Mediterranean. The venom of the latter has been studied by A. Briot,143who sectioned the dorsal and opercular spines, and macerated them either in physiological saline solution, or in glycerine; he then tested the toxicity of these macerations on certain animals—frogs, rabbits, and rats.

Fig.104.—Scorpæna diabolus(Indian and Pacific Oceans). (After Savtschenko.)

The frogs alone exhibited, as the result of subcutaneous injection into a limb, slight transient paralysis. No effect was found to be produced by the venom when injected intravenously into the rabbit, or subcutaneously into the rat.

The poison-apparatus ofScorpænais situated in the spiny rays of the dorsal and anal fins. These rays are enveloped in the inter-radial membrane, which forms a sheath for them, and are scored with a double cannelure. At the bottom of these grooves are thesecreting cells, which are elongate, pressed one against the other, and supported at the base by a highly vascular substratum of connective tissue. The venom flows out between the layer of cells and the ensheathing membrane, which is capable of being pushed slightly back as the result of the penetration of the spine into the tissues, and then exerts pressure upon the reservoir. The latter is formed by the distension of the sheath under the pressure of the secreted liquid.

Fig.105.—Pterois artemata(East Coast of Africa, Indian and Tropical Pacific Oceans). (After Savtschenko.)

There are twelve pairs of dorsal and three pairs of anal glands.The pairs attached to the second anal spine are, as the direct result of the size of the latter, more developed than those of the other spines.

In theRascasse, the opercular spines of which are greatly developed, there is a rudiment of a poison-apparatus at the bottom of the sheath formed by the skin of the gills.

The species ofPterois(fig. 105) are distinguished from those ofScorpænaby their dorsal fins, the rays of which are very long and curved backwards, above the membrane by which they are united. They are found in the Indian and Equatorial Pacific Oceans, and are very beautiful in colour, varying from reddish-brown to bright rose.

The poison-apparatus of these fishes is situated in the dorsal fin, and is precisely similar to that ofScorpæna.

Fig.106.—Pelor filamentosum(FamilyTriglidæ, Mauritius).

The species ofPelor(fig. 106) present greater resemblance to those ofSynanceia, owing to their heads being crushed in in front. Their eyes stand up above the head and are very close together, which helps to give them an extremely ugly appearance. The skin is soft and spongy, and bristles with jagged fleshy shreds.

Their poison-apparatus is placed in the dorsal fins, as in the case ofScorpænaandPterois.

GenusTrachinus(Weevers).—Four species of Weevers are found in European seas: the Greater Weever (Trachinus draco), the Lesser Weever (T. vipera), the Striped-headed Weever (T. radiatus), and the Mediterranean Spider Weever (T. araneus); other species are met with on the coast of Chile.

Weevers possess two sets of poison-apparatus, one of which is situated on the operculum, the other at the base of the spines of the dorsal fin (fig. 107).

Fig.107.—Trachinus vipera(Lesser Weever).

The spine surmounting the operculum exhibits a double cannelure connected with a conical cavity excavated in the thickness of the base of the opercular bone. This spine is covered with a sheath, beneath which lie the secreting cells. The gland is an offshoot from the skin, and appears as a simple follicle invaginated in the opercular bone (fig. 108).

The dorsal apparatus is composed of from five to seven spines, to which the inter-radial membrane forms an adherent sheath which extends almost to the end of the rays. Each spine exhibits a deep double cannelure. The venom flows between the layer of cells clothingthe cannelures and the skin, which is distended to allow it to pass.

Towards the base of the spine, the edges of the cannelure are united, and form a hollow, bony cone, the walls of which are lined with the cells that secrete the toxic fluid.

Fig.108.—A, Operculum and opercular spine of the Lesser Weever (Trachinus vipera);ar, articular surface of the operculum;c. op, body of the opercular spine;c. an, canal of the spine;z, space occupied by the poison-gland.B, Spine belonging to the first dorsal fin;c. an, efferent poison-canal in the spine.

Greater Weevers are usually from 12 to 30 cm. in length, and of a reddish or yellowish-grey colour, with blue or violet spots. They are caught in trawls and are fairly common on sandy bottoms. In the month of June they approach the shore for the purpose of spawning.

The venom of the Weever has formed the subject of interesting studies by Günther, Gressin,144Bottard, Phisalix,145and more recently by Kobert146and A. Briot.147

In order to procure sufficient quantities of it for experimental purposes, Briot cuts off the venomous spines and the surrounding tissue with a pair of scissors; he then pounds the whole in a mortar, and mixes the pulp with pure glycerine. After filtration through paper, a toxic solution is obtained, which does not deteriorate by keeping, and is neutral to litmus.

A few drops of this liquid are sufficient to kill guinea-pigs, which, immediately after receiving an injection in the thigh, exhibit paralysis of the leg with tetanic convulsions; twenty-four hours later an eschar is formed, and death supervenes on the second or third day.

Two or three drops, introduced into the marginal vein of the ear of a rabbit, cause death from asphyxia in from four to ten minutes. The heart continues to beat for a fairly long time after respiration has entirely ceased; the blood is not coagulated.

The toxicity of this venom is completely destroyed by heating it to 100° C., by chloride of lime, and by chloride of gold. Antivenomous serum prepared from horses vaccinated against cobra-venom has absolutely no effect upon itin vitro. There is therefore no affinity between this venom and that of snakes.

Weever-venom dissolves the red corpuscles of the horse in the presence of normal heated horse-serum, but does not dissolve them in the presence of fresh serum. The non-heated serum, therefore, as I have shown with reference to the action of cobra-venom on the blood, contains a natural antihæmolysin.

Briot succeeded in vaccinating rabbits by accustoming them to the venom, and in obtaining from them a serum capable of neutralising the latterin vitro, and of immunising fresh rabbits against doses several times lethal, even when injected intravenously.

According to Gressin, the following phenomena are produced in man as the result of Weever-stings:—

“At first there is felt an excruciating, shooting, paralysing pain, which, in the case of nervous persons, may cause attacks of leipothymia ending in syncope. A kind of painful formication next pervades the injured limb, which becomes swollen and inflamed, and may even, if treatment be neglected, form the starting point of a gangrenous phlegmon.

“This condition is frequently accompanied by certain general phenomena—such as fever, delirium, and bilious vomiting, the duration of which is variable, since they may only last for two or three hours, or may continue for several days. Fishermen rightlyconsider this variability to depend upon the amount of venom that has penetrated into the wound, and especially upon the season at which the accident takes place. The most serious results are recorded during the spawning season, and fishermen regard the Lesser Weever as being the more poisonous.”

In the fishes belonging to this family the body is elongated and depressed, while the spines in the anterior dorsal fin and in the ventral fins are slender, flexible, and seldom very solid. The ventral fins are inserted on the breast or on the throat, and are either separated or united together in the shape of a funnel. The skin is naked or covered with large scales, and the mouth is furnished with teeth. The males are distinguished by the presence of a long genital papilla. These fishes are carnivorous.

Fig. 109.—Callionymus lyra(Dragonet or Skulpin. FamilyGobiidæ).

Several species of venomousGobiidæare met with on the shoresof France and in the tropical zone. The most important of these belong to the genusCallionymus(C. belennus,C. lacertus,C. vulsus, andC. lyra—fig. 109).

The Dragonet or Skulpin (Callionymus lyra), which is common on the coast of Calvados, may attain the length of 30 cm. In France it is popularly known as theDoucet,Dragonnet,Lavandière,Cornaud, orCapouri. Its colours are very vivid, orange and deep lilac.

In this fish the præopercular bone ends in three strong, conical, and very sharp points, diverging like the prongs of a trident. The upper margin of the opercular bone bears another point, which is directed upwards.

The skin of the gills forms a common sheath for this defensive armature, and the base of the sheath is prolonged into two culs-de-sac, the surface of which is clothed, during the spawning season, with cylindrical cells, the secretion of which is poisonous.

This venom, which is small in amount, does not appear to have any marked effect upon man (Bottard).

This family ofAcanthopterygiiincludes several species of brilliantly coloured fishes with elongated and laterally compressed bodies, provided with a long dorsal fin, and having, on each side of the tail, a sharp spine placed in front of the anal fin. They are herbivorous, and are confined to the tropical seas.

The principal genera are:Teuthis(India),Acanthurus(Tropical Atlantic),Prionurus(Japan), andNaseus(Red Sea and Indian Ocean). The fishermen of Réunion are much afraid of the wounds inflicted byAcanthurus luridus, which they callMarguerite PorcorGrande Marguerite. A sting from this fish causes a very acute smarting pain, which may last for several hours, but usually has no serious consequences.

The poison-apparatus of these fishes is situated in the dorsal and anal fins, as inScorpæna.

The venomous species belonging to this family are few in number. They are found in all tropical seas, but have no representatives in Europe. The best-known species areBatrachus tau(shores of Central America), andB. grunniens, or Grunting Batrachus (fig. 110).

Fig. 110.—Batrachus grunniens(West Indies).

Fig. 111.—Thalassophryne reticulata(Panama; Tropical Pacific). (After Savtschenko.)

The Grunting Batrachus, which does not exceed 30 cm. in length, is especially common in West Indian waters. When taken from the water it makes a peculiar grunting sound, whence its name is derived. The pectoral fins are reddish, the back is brown, and the sides are yellow, marbled with black. It has three spines in the anterior dorsal fin, and a fourth spine on the top of the operculum, with a small poison-sac at the base of each.

Next to this genus come the species ofThalassophryne,T. reticulata(fig. 111), found on the shores of Panama, andT. maculosa, of Bahia (Brazil), which are provided with a precisely similar poison-apparatus.

The physiological action of the venom of these two species has not yet been studied, but it is probable that it does not differ from that of the venom of the Weevers and the species ofSynanceia.

Fig. 112.—Lophius setigerus(China Sea and Sea of Japan). (After Savtschenko.)

The fishes belonging to this family are of large size and compact shape, with the anterior part of the body greatly expanded. The head, which is broad, bears venomous spines, and the mouth is furnished with large teeth. These fishes are voracious, and liein wait for their prey at the bottom of the water in the mud of the shore. In order to attract it, they make use of cutaneous appendages attached to their spines, which they are able to elevate, and of filaments situated near the mouth.

The principal genus isLophius, one species of which,L. setigerus(fig. 112), is found in the seas of China and Japan. Another species,L. piscatorius(the Sea Devil or Angler), occurs in the temperate climates of Europe, North America, Asia and Africa.

Certain otherAcanthopterygiiarecapable of inflicting wounds, but, although fishermen often believe them to be venomous, or such properties are frequently attributed to them in stories, it is doubtful whether they possess poison-glands. The accidents produced by them are due rather to the fact that the spines in their fins are extremely sharp, and that their flesh is toxic. Those belonging to thePercidæ(the Perch family), especially the genusSerranusandS. ouatabili(fig. 113) in particular, are above all remarkable in this respect. The last-mentioned fish has two or three spines on its operculum.

Fig. 113.—Serranus ouatabili.(After Savtschenko.)

The same may be said of certainSquamipinnes, another family ofAcanthopterygii, whose stout bodies are brightly coloured, and have very sharp, spiny rays in their dorsal and anal fins. Themost curious genus among the fishes belonging to this family isHolacanthus, in which the præoperculum is provided with an enormous spine like that of the Weever.Holocanthus imperator(fig. 114) is met with fairly often in the Indian Ocean and Malay Archipelago.

Fig. 114.—Holacanthus imperator(Indian Ocean and Malay Archipelago). (After Savtschenko.)

The OrderPlectognathi(FamilyGymnodontes) includes the generaDiodon,TetrodonandTriodon, globular fishes, in which the jaw is transformed into a beak and furnished with a sharp dentary plate. Their œsophagus is dilated into a resonant air-pouch. When removed from the water they swallow air and dilate the pouch, and the expulsion of this air is accompanied by a loud noise.

Several species ofTetrodonare armed with spines, which producevery painful wounds. Their flesh is toxic, but it has not been proved that poison-glands exist at the base of the spines.

On the shores of the Cape of Good Hope, Brazil, China, and Japan these fishes are much feared. The principal species areTetrodon stellatus(Indian and Pacific Oceans;fig. 115) andT. rubripes(Japan;fig. 116).

Fig. 115.—Tetrodon stellatus(Indian and Pacific Oceans). (After Savtschenko.)

Fig. 116.—Tetrodon rubripes(Japan). (After Savtschenko.)

Closely allied toDiodon, and feared like the foregoing on accountof their spines, which are sometimes scattered all over the body, are the species of the genusChilomycterus, the most important of which areC. orbicularis(fig. 117), andC. tigrinus(fig. 118), both of which are found in the Indian Ocean.

Fig. 117.—Chilomycterus orbicularis(Indian Ocean). (After Savtschenko.)

Fig. 118.—Chilomycterus tigrinus(Indian Ocean). (After Savtschenko.)

This Order is characterised by the presence of a pneumatic duct to the air-bladder. It consists of a large, number of families, only two of which, theSiluridæandMurænidæ, include venomous species.

The majority of the very large number of species belonging to this family live in fresh water, and have the free margin of the lips almost always furnished with barbules (Silurus glanis;fig. 119). A few of them possess a poison-apparatus, which, however, attains its greatest development inPlotosus, the only genus ofSiluridæfound exclusively in the sea.

The species ofPlotosusfrequent the shores of the Indian Ocean, and are met with in the Seychelles, Réunion, and Mauritius. In shape they resemble eels, and they bury themselves in the sand or mud, a habit which renders them very dangerous to fishermen.

Fig. 119.—Silurus glanis(Rivers of Central and Eastern Europe).

Plotosus lineatus, which is of a greenish-brown colour, striped with from four to six longitudinal whitish bands, is the most common. By the Creoles of Mauritius and Réunion it is calledMachoiran, by the MalaysSambilang, and by the AbyssiniansKoomat.

Its poison-apparatus is situated at the base of the dorsal and pectoral spines. These spines are strong, sharp, slightly incurved,and furnished with hooked denticulations, which cause them to remain in the wound, in which they break off. Near their extremity there opens a small canal, which communicates with the culs-de-sac situated at the base of the spiny rays, which produce a venomous secretion. The dorsal spine has only a single cul-de-sac, while the pectoral spines have two.

The contraction of the local muscles, by compressing these culs-de-sac, can cause the venom to make its way into the canal of the spine, but the fluid does not spurt forth in a jet as in the case ofSynanceia. The poison-apparatus is therefore passively defensive in character.Plotosusis capable of wounding only when the hand or foot is placed on its dorsal or pectoral spines.

Fishermen who are stung immediately feel an excruciating pain, which is soon accompanied by fever, and lasts for several days. Accidents caused by this fish are of fairly common occurrence in Réunion.

Of the fishes belonging to this family, the species of the genusMurænaalone concern us. They have an elongated body, without pectoral fins, and a naked skin, covered with a thick layer of viscid slime, as in the case of the eels. Their dentition is powerful, formed of long, recurved fangs, arranged in one or more rows. These fishes may attain a large size, exceeding 2 metres in length. More than one hundred species are known, all of which live in tropical or subtropical seas.Muræna helenais common in the Mediterranean in the vicinity of Nice and Toulon;M. moringa(fig. 120) is found in the Tropical Atlantic.

The species ofMurænalive in deep water, and feed upon fishes or crustaceans. In hot countries they frequently venture into fresh water. Their skins are adorned with brightly coloured markings, which vary very greatly according to the species.

The poison-apparatus inMurænaconsists of a pouch situatedabove the membrane of the palate, which may contain ½ c.c. of venom, and three or four conical, curved teeth, with the convex surface in front, as in the fangs of snakes. The teeth are not pierced by a central canal, and the venom flows between them and the mucous membrane of the palate, which forms a sheath. The latter is withdrawn to the base of the teeth, while they are penetrating the tissues. The teeth are mobile; they are articulated with the palatine bone, in which they are inserted in small depressions, and a resistant fibrous tissue serves as the means of union. They can be deflexed backwards against the mucous membrane of the palate; in this position the first, second and fourth tooth (when the latter exists) disappear completely between the folds of the membrane. The third tooth normally remains erect, and it is this by which wounds must in most cases be inflicted. None of these teeth can be protruded beyond the vertical.

Fig. 120.—Muræna moringa(Tropical Atlantic). (After Savtschenko.)

In addition to the palatine teeth there are, among the groups of maxillary teeth, several mobile teeth, which are connected with the poison-reservoir.

Besides its toxic action the venom ofMurænahas manifest digestive properties, and, in the case of a fish which has been dead for some little time the gland is no longer to be found, since its walls have undergone a rapid autodigestion.

The venoms of all the fishes of which I have just given a brief description, as regards their physiological action, present a fairly close resemblance to the venom of the Weever, and show scarcely any variation except in the intensity of their effects. They have been but little studied hitherto, and it is desirable that they should be better understood.

By the ancients the venom ofsalamandersandtoadswas dreaded as much as the most terrible poisons. These animals, however, are not very formidable, since they are devoid of inoculatory organs; their poison-apparatus is localised exclusively in the parotids and the skin. It is represented simply by more or less confluent glands in the form of sacs, secreting a viscid mucus, which has a nauseous odour and is highly toxic, even to animals of large size.

The salamander belongs to the OrderUrodela, which is characterised by the persistence of the tail. Its body is heavy and thickset, and the flanks and the sides of the tail exhibit a series of glandular crypts, which secrete venom.

“The mucus which flows from the mouth, and resembles milk, eats away human hair,” wrote Pliny; “the spot moistened by it loses its colour, which subsequently returns. Of all venomous animals the salamander is the most terrible; it is capable of annihilating whole nations by poisoning the vegetation over a vast area. When the salamander climbs a tree all its fruit is poisoned, and those who eat of it die as surely as if they had taken aconite. Moreover, if bread be baked with wood touched by the animal, it is dangerous, and may occasion serious disorders. If the naked foot be defiled with the saliva of this creature, the beard and hair soon fall out. Sextius says that a salamander, preserved in honey, after theremoval of the entrails, head, and limbs, acts as a stimulant if taken internally.”

In ancient Rome, and also in Mediæval France, it was believed that the most furious fire could be extinguished simply by contact with one of these animals; charlatans sold the inoffensive salamander, which, if cast into the most terrible conflagration, was bound, they declared, to arrest its disastrous progress!

The explanation of this superstition is furnished by Duméril, who writes: “On being placed in the middle of burning charcoal, these victims of so cruel a curiosity, when put to the test, instantly allowed to exude from the many pores with which their skins are riddled a slimy humour, sufficiently abundant to form a viscid layer over that part of the glowing charcoal with which the animals were in contact. Since this surface, being no longer exposed to the air, immediately became quite black, it was supposed to be extinguished; but the salamanders sustained such severe burns that they soon succumbed.”148

The principal species of salamanders are:—

Salamandra atra(Black Salamander), which is found in the Alps and the mountains of Central Europe, close to the snow-line, and up to an altitude of 3,000 metres.

Salamandra maculosa(Spotted Salamander,fig. 121), distributed throughout almost the whole of Europe, and also found in North Africa.

Triton cristatus(Crested Newt), likewise common all over Europe.

Triton marmoratus(Marbled Newt,fig. 122), which is met with in damp and dark places, in Portugal, Spain, South and Central France, and as far north as the Forest of Fontainebleau.

Cryptobranchus japonicus(Great Japanese Salamander, fig. 123), which often exceeds 1 metre in length, and has a clumsybody covered with large warts, and an enormous head, broad behind and flattened in front.

This giant salamander is now confined to a few provinces in the centre of Japan, between long. 34° and 36°, in damp, shady places, from 200 to 800 metres above sea-level. It is eaten by the Japanese, who also use it as a remedy for, or prophylactic against, contagious disorders. By nature it is extremely sluggish, but tries to bite when irritated, and then covers itself copiously with slime.

Fig. 121.—Salamandra maculosa(Europe and North Africa).

Fig. 122.—Triton marmoratus(male). (Europe.)

The venom secreted by salamanders evidently serves to protect these creatures against their enemies. So long ago as 1866,Zaleski149isolated from it a substance soluble in alcohol, insoluble in ether, and with a very strong alkaline reaction, to which he gave the namesalamandarin. This substance, which is better known to-day assalamandrine, has been studied afresh by A. Dutartre,150Phisalix and Langlois,151and subsequently by Edwin and S. Faust.152

Fig. 123.—Cryptobranchus japonicus(Great Japanese Salamander).

The action of this poison on the frog is characterised by a period of violent convulsions, with general tetanic crises, followed by a period of paralysis, with arrest of respiration and complete muscular relaxation. According to the quantity of poison absorbed, this paralytic period may be followed by death, with arrest of the heart in diastole, or else by return to life, with more or less acute recurrence of convulsions.

S. Faust prepares salamandrine by pounding up whole salamanders in a small quantity of physiological saline solution. The thick pulp obtained in this way is filtered. One cubic centimetre of the filtrate, taken as a unit, contains about 5 decimilligrammes of active substance, which can be purified by treating the filtrate with alcohol, which dissolves the salamandrine and precipitates all the proteic substances that give biuret reaction. The salamandrine thus freed from proteins is saturated with sulphuric or phosphoric acid, when there is formed a crystallisable salt, which is washed and dried. This salt is soluble in alcohol and in water. Its chemical composition is as follows:—

C52H80Az4O2+ H2SO4.

The toxicity of this substance is such that from 7 to 9 decimilligrammes per kilogramme represent the lethal dose for dogs, when injected subcutaneously. The lethal dose for the rabbit isstill smaller. It produces convulsive phenomena, followed by arrest of respiration. The administration of chloral to the subjects of the experiment, either preventively or immediately after the poison, prevents the latter from taking effect. Besides salamandrine, S. Faust has isolated a second alkaloid,salamandridine, which, as a sulphate, corresponds to the formula (C20H31AzO)2+ H2SO4, crystallises in rhombic prisms, and is soluble with difficulty in water. The only difference between the two alkaloids is formed by a methylpyridic group, and both are derivatives of quinoline. They must therefore be considered as identical with the exclusively vegetable alkaloids.

S. Faust concludes from his physiological investigations that salamandrine takes effect upon the central nervous system, especially upon the respiratory centres. It is a convulsion-producing poison, comparable to picrotoxin, but its effects differ from those of the latter substance in that the convulsions are accompanied by tetanic spasms.

The venom of the Japanese Salamander (Cryptobranchus japonicus) has formed the subject of studies by Phisalix.153This investigator has shown that this venom, which is highly soluble in water and in glycerine, is very unstable; alcohol and heating for twenty minutes at 60° C. are sufficient to destroy it. When inoculated into frogs it produces œdema and hæmorrhage; if injected into warm-blooded animals it causes necrosis. In sufficiently strong doses it kills by arresting respiration. Its effects strongly resemble those produced byViperinevenoms. This venom, if attenuated by being heated at 50° C. and injected into mammals, vaccinates them and leads to the formation in their blood of antitoxic substances, which are capable of preventing intoxication by salamander-venom, and, curiously enough, also confer immunity against viper-venom and the serum of the common snake.

Toadsare easy to distinguish from frogs owing to their squat and clumsy shape, and to the mass of glands with which each side of the neck and a more or less extensive portion of the body is furnished in these animals. According to G. A. Boulenger, the number of known species amounts to seventy-six, which are found in the Old and New Worlds, but have no representatives in Australia. The species that are the most common, and most interesting from the point of view of their venoms, are:—

The Common Toad (Bufo vulgaris), in which the skin, which is very thick and rugose, is covered on the back with large rounded tubercles with reddish summits. This species is a great destroyer of insects, and, as such, is very useful to agriculturists.

The Natter-Jack (Bufo calamita), in which the digits are palmate at the base. When irritated it contracts its skin and covers itself with a white frothy exudation, which gives off an odour of burnt powder.

The Green Toad (Bufo viridis), which is especially abundant in Southern Europe, the Levant, and North Africa.

The Musical Toad (Bufo musicus), a species distributed throughout North America as far south as Mexico, and in which the back is covered with pointed conical tubercles resembling spines.

The Brown Pelobates (Pelobates fuscus), common in the neighbourhood of Paris, the skin of which is almost entirely smooth. Although it appears to be nearly destitute of glands, this animal secretes a very active venom, which has a penetrating odour and kills mice in a few minutes, producing vomiting, convulsions, and tetanic spasms of the muscles.

The toxicity of the venom of toads was long ago demonstrated by the experiments of Gratiolet and Cloëz.154It is manifest only in the case of small animals, and in man merely produces slight inflammation of the mucous membranes, especially of the conjunctiva.

That this venom preserves its toxic properties for more than a year in the dry state was shown by Vulpian, and satisfactory studies of its composition and physiological action have been made by Fornara,155G. Calmels,156Phisalix and Bertrand,157Schultz,158Pröscher,159and S. Faust.160

Toad-venom was prepared by Phisalix and Bertrand in the following manner: Holding the head of one of these batrachians under water, they expressed the contents of the parotid glands with the fingers or with a pair of forceps. They repeated the same operation with a second, and then with a third toad, until they had sufficiently impregnated the water, which serves to dissolve the venom. In this way they obtained an opalescent, acid liquid, which they filtered with a Chamberland candle under a pressure of from four to five atmospheres. There remained on the filter a yellowish substance, with a highly acid reaction and partly soluble in ether and chloroform, while there passed through the pores a clear, reddish, and slightly acid liquid, which on being evaporated left behind a greyish-white precipitate. This precipitate was separated by filtration, washed in water, and redissolved in absolute alcohol or chloroform. The albuminoid matters were thus separated, and the liquid, after being rendered limpid by filtration, was evaporated away. The substance obtained in this way represents one of the two active principles of the venom. It acts on the heart of the frog, and arrests it in systole. It assumes the appearance of a transparent resin, the composition of which roughly corresponds to the formula C119H117O25. It is thebufotalinof Phisalix and Bertrand, and is probably identical with that obtained by S. Faust,the formula of which, according to the latter author, is said to be C11H23O5.

Bufotalin is readily soluble in alcohol, chloroform, acetone, acetate of ethyl, and acetic acid. When water is added to a solution of it in alcohol it is precipitated, giving a white emulsion, which has a very bitter taste.

From the aqueous extract whence the bufotalin has been separated, it is possible to separate a second poison, which acts on the nervous system and causes paralysis. In order to obtain it in a pure state, the extract is treated with alcohol at 96° C., filtered and distilled; the residue dissolved in water is defæcated with subacetate of lead and sulphuretted hydrogen. The solution thus obtained is successively exhausted with chloroform to extract the cardiac poison, and with ether, which removes almost the whole of the acetic acid. The second neurotoxic principle, calledbufotenin, remains in the residue of the solution after being evaporatedin vacuo.

Toad-venom, therefore, contains two principal toxic substances:bufotalin, which is of a resinoid nature, soluble in alcohol, but scarcely soluble in water, and is thecardiac poison; andbufotenin, which is readily soluble in those two solvents, and is theneurotoxic poison.161

Pröscher, on the other hand, has extracted from the skins of toads a hæmolytic substance, termed by himphrynolysin, which possesses all the properties of a true toxin and is not dialysable. It is obtained by pounding the skins with glass powder in physiological serum.

Phrynolysin dissolves the red corpuscles of the sheep very rapidly, and (in order of sensitiveness) those of the goat, rabbit, dog, ox, fowl, and guinea-pig. The red corpuscles of the pigeon, frog, and toad are scarcely affected. When heated at 56° C. itloses its properties. By the ordinary methods of immunisation it is possible to obtain a very active antilysin.

There is, therefore, a very close analogy between the venoms oftoadsandsalamanders. These highly complex substances are composed of mixtures of poisons, some of which are in all respects analogous to the vegetable alkaloids, while others are closely related to the microbic toxins and snake-venoms.

In the spawning season the cutaneous glands of the male toad are gorged with venom, while those of the female are empty. Phisalix162has shown that at this period the venom of the female is accumulated in the eggs, which, if extracted from the abdomen at the moment of oviposition and driedin vacuo, give off in chloroform a product that has all the toxic properties of cutaneous venom (bufotalin and bufotenin). No trace of this poison is to be found in the tadpoles.

The OrderLacertiliaincludes only a single venomous species, which belongs to the familyLacertidæ, and is known as theHeloderm(Heloderma horridum,fig. 124). It is a kind of large lizard, with the head and body covered with small yellow tubercles on a chestnut-brown ground. It sometimes exceeds a metre in length, and its habitat is confined to the warm belt extending from the western slope of the Cordilleras of the Andes to the Pacific. It is met with especially in the vicinity of Tehuantepec, where it inspires the natives with very great dread. It is a slow-moving animal, and lives in dry places on the edges of woods. Its body exhales a strong, nauseous odour; when it is irritated, there escapes from its jaws a whitish, sticky slime, secreted by its highly developed salivary glands. Its food consists of small animals. Its bite is popularly supposed to be extremely noxious, but, as a rule, the wound, though painful at first, heals rapidly.Sumichrast caused a fowl to be bitten in the wing by a young individual, which had not taken any food for a long time. After a few minutes the parts adjacent to the wound assumed a violet hue; the bird’s feathers were ruffled; a convulsive trembling seized its entire body, and it soon sank to the ground. At the end of about half an hour it lay stretched out as though dead, and from its half-open beak there flowed a sanguinolent saliva. There was no movement to give any sign of life, except that from time to time a slight shiver passed through the hinder part of its body. After two hours, life seemed gradually to return, and the bird picked itself up and crouched on the ground, without, however, standing upright, and still keeping its eyes closed. It remained thus for nearly twelve hours, at the end of which time it once more collapsed, and expired.

Back to Index Next