Chapter 9

D 15

This is the history of asyphilitic and a sexually immoral couple. They were never married, and the woman for many years supported the man, who was never sober and frequently had attacks of delirium tremens. She finally deserted him. Of their eight children two werestillbirths, three were epileptic, and the other syphilitic. One of the epileptics in a jealous rage shot the woman whom he loved, and when he found that escape was impossible, killed himself.

D 15a-b

Charts explaining the method of collecting and recording data.

Exhibited by Mr E. J. Lidbetter.

A selection by Mr. E. J. Lidbetter, from his collection of pedigrees, showing pauperism in association with mental and physical defect, justifying the inference that a high proportion ofpauperism is to be attributed to the transmission of defectand the perpetuation of stocks of a low type:—

E 1

Pedigree showingmental disease and destructive eye-diseasein the same stock. Insanity, epilepsy, feeble-mindedness and idiocy in various degrees in twelve members, several of them being also blind; partial or total blindness from detachment of the retina without mental defect in several others. Tendency to "anti-dating" or "anticipation" of the mental disease in succeeding generations or younger born offspring. The printed numbers on the diagram indicate the age of the individual on 1st attack. Prevalence of tuberculosis (three members). Neither mental nor ocular conditions attributable to syphilis. Of the 49 individuals whose history is known 26 have been, or are being, maintained in public institutions (Asylums, Workhouses, Blind Schools, or Poor Law Schools), 29 have been paupers at intervals, and two are known to have been in prison. Several marriages between mental defectives yielding large but inferior families. (Exhibited by Mr. E. T. Lidbetter. The eye-disease reported upon by Mr. E. Nettleship.)

E 2

Pedigree showing the tendency tointermarry among pauper and defective families. On the left "able-bodied" pauperism and on the right sickness. One hundred and fifty-seven units shown in five generations; 76 paupers shown, including 38 classed as chronic, 32 occasional and six medical only. Twenty-eight died in infancy, nine tuberculous, six insane, two epileptics, and one blind. Shows also pauper children born in lucid intervals of parent suffering from periodic insanity.

E 3

Pedigree illustrating stock of alow type in which very little physical defect appears. The total includes 61 individuals, of whom 42 are or have been paupers, eight have died in workhouse orinfirmary, and two in asylums for lunatics; one child is an imbecile. On the whole the stock may be described as mentally sub-normal (not strongly so), but with a marked non-moral tendency. Of the 34 children in the last generation, ten are certainly illegitimate; 15 were, or are, being brought up in Poor Law Institutions, and nine received out-door relief with their parents. The collective period of pauperism in this case exceeds 115 years and the cost to the ratepayers is estimated at about £2,400.

E 4

Showing the case of a woman who had two husbands. With the first her children were consistently defective (deaf and dumb). With the second, one died in infancy and three are doing well. All the children of the first are, or have been, paupers.

E 5

A series showing the intimaterelation between tuberculosis infant mortality and pauperism:—

E 5a

Showing atuberculous family with apparently normal parents, both of whom come from tuberculous stocks. Of their 14 children only two are normal; six are consumptive; four died in infancy. The father was one of a family of 8 of whom only he and one other survived—and that other became insane, and his wife and children became paupers in consequence.

E 5b

Showinginsanity, consumption and infant mortality; also the transmission of insanity through the apparently normal.

E 5c

Showing thesurvival of tuberculousstock by accession of strength from the normal. Only the illegitimate children and their non-sick father survive in this group.

E 5d

Showing the case of anormal woman who had two consumptive husbands. Survival of defective strain by accession of strength from the normal.

E 5e

Consumptionin three generations.Male infant mortality. Query, transmission (?) through the normal.

E 6

A series showingtransmission of mental defect through the apparently normal.

E 6a

Insanity, blindness, epilepsy and feeble-mindedness.

E 6b

Insanity in three generations. Transmission through the normal in each case.

E 6c

Insanity through the normal twice removed.

E 6d

Insanity, epilepsy, and infant mortality—a Mendelian suggestion.

EXHIBITED BY PUBLIC HEALTH DEPARTMENT, CITY OF LIVERPOOL.

E. W. Hope, M.D., M.O.H.

F 1

One large model ofinsanitary propertydealt with in Liverpool, built to scale, etc., with glass cover.

F 2

Charts showing thedecline in mortality from phthisis:—

F 2a

One showing rate for England and Wales.

F 2b

One " " England and Ireland.

F 2c

One " " Scotland.

F 2d

One " " Liverpool.

F 3 b c d e f

Six framed and glazed photographs illustrating insanitary property which has been demolished in Liverpool, and the new dwellings which have been erected to house the dispossessed tenants.

AN EXHIBIT OF A SYSTEM OF MAKING PEDIGREE RECORDS.

Exhibited by Dr. Raymond Pearl,

Biologist of the Maine Agricultural Experiment Station, Orono, Maine.

This exhibit consists of a series of blank record forms designed toillustrate the method of keeping pedigree recordswhich has been in use at the Maine Agricultural Experiment Station for a period of five years, in connection with its work in the experimental study of inheritance in poultry and in various plants. The advantages which have been found by experience to inhere in this system of pedigree record keeping are (a) simplicity; (b) ease of operation; (c) small chance for error in the keeping of large masses of pedigree records; (d) uniformity of the system, such that records of all kinds, in any way pertaining to the work, may be brought together with great ease for consultation or study.

In addition to the record blanks there are exhibited also various marking devices and other apparatus connected with the proper working of the plan.

It should be noted that while the blanks here exhibited are devised particularly for work with poultry and plants, the same system, with slight modifications, may be successfully applied to the keeping of human pedigree records; indeed it is a pleasure to statethat the system here exhibited is an outgrowth and development of a scheme for the keeping of pedigree data in general and particularly human pedigree records suggested many years ago by the late Sir Francis Galton.

Exhibited by C. V. Drysdale, Esq., D. Sc.

TheMalthusian theory of populationleads to the conclusion that the population of the majority of countries is held in check by lack of food. Therefore, there should be a correspondence between the birth and death rates, high birth rates producing high death rates and high infantile mortality, and the death rate should rise or fall with a rise or fall of the birth rate.

In the accompanying diagrams, white strips imply birth rates, shaded strips death rates, and black strips infantile mortality, or deaths of children under one year.

H 1

Shows the relation betweenbirth and death rates and infantile mortalityin various countries in 1901-1905.

Figure H 1.

H 2

Relation betweenbirth rate andcorrecteddeath ratesin various countries. (This shows that France is healthier than appears in H 1.)

H 3

Shows relation betweenbirth and death ratesfrom various causes in five districts ofLondon.

H 4

Relation between thebirth rate and death ratefor various arrondissements ofParisin 1906. (Note that the increase in the Elysée quarter is as high as the average in the quarters of high birth rate.)

H 5-6

Variation of thetotal population and birth and death ratesin theUnited Kingdomand theGerman Empire. (Note that the fall in the death rate corresponds fairly closely to that in the birth rate.)

H 7

Id. forFrance. (Note that the population is still increasing although slowly.)

H 8

Birth and death rates for Francesince 1781. (Note that the rate of increase of population in 1781 was no higher with a birth rate of 39 per 1,000 than in 1901-6 with a birth rate of only 21 per 1,000. A fall of 17.8 per 1,000 in the birth rate has resulted in a fall of 17.5 per 1,000 in the death rate.)

H 9

Birth and death rates and infantile mortality for England and Wales. Alsomarriage rate, fertility of married women, illegitimacyandvariation of diseases. (Note that the illegitimate birth rate has fallen to half since the fall of the birth rate set in.)

H 10

Birth and death rates and infantile mortalityin theNetherlands(Notice the rapid increase of population as the death rate falls, and the great fall of infantile mortality, probably due to the practical work of the Dutch Neo-Malthusian League among the poor.)

H 11-13

Protestant Countries.(Notice the correspondence between the birth and death rates and infantile mortality in all.)

H 14-16

Roman Catholic Countries.(Note that the fall of the birth rate has taken place almost equally with that in the Protestant Countries, and with the same result.)

H 17-20

The onlyfour countries in which the birth rate is approximatelystationary. (Notice that the death rate has not fallen—except, perhaps in Russia—and that the infantile mortality has not fallen. Also that the highest birth rate produces the highest death rate and infantile mortality, and the lowest birth rate the lowest mortality.)

H 21-24

The onlyfour countries withrisingbirth rates.The death rate and the infantile mortality have increased in every one.

H 25

Australia.The death rate has fallen with the birth rate, and is now only about 10 per 1,000.

H 26

New Zealand.The only country in which the fall in the birth rate has not produced a fall in the death rate, and which is not therefore over-populated. The infantile mortality is the lowest in the world, and the death rate less than 10 per 1,000, which gives us an ideal which we can reach in all countries by lowering the birth rate sufficiently.

H 27

The City of Toronto.The birth rate has fallen and afterwards risen. The death rate has fallen with the birth rate, and afterwards risen, showing that the improvements in sanitation have not been the cause of the falling death rate in other countries.

H 28

Berlin.The birth rate rose rapidly from 1841 to 1876, and afterwards fell even more rapidly. The death rate, except for epidemics and wars, rose and fell in almost precise correspondence with the birth rate.

H 29-30

Europe and Western Europe.These show that the total population of Europe is increasing faster, the more the birth rate falls, while in Western Europe the birth and death rates correspond almost exactly. Calculations made from this show that about 25,000,000 fewer deaths have occurred in Europe since 1876, due to the fall in the birth rate caused by the Knowlton Trial and the Neo-Malthusian movement. It should be noted that in the great majority of cases the decline of the birth rate commenced in 1877, the year of the Knowlton Trial.

(SEE SUNDBARG'S APERÇUS STATISTIQUES INT'ONAUX 1905. pp. 76 & 80.)

Figures H 29-30

Exhibits lent by Mr. and Mrs. W. C. D. Whetham.

I 1

1. Pedigree showing the descent of Administrative Ability.

I 2

2. Wollaston Pedigree, showing the descent of Scientific Ability.

I 3

3. Pedigree showing the Mendelian descent of Eye-colour in mankind.

The Racial Form of Nose and Its Segregative Inheritance.

ByGeo. P. Mudge.

Theform of a nosedoubtless depends upon many factors. But chief among them we may suppose are the length, breadth, and angle of inclination of the nasal bones; the form, length, breadth, and thickness of the nasal septum, and the degree of development of the turbinal bones. The segregation and persistence in families of a definite type of nose-form is a subject well worth further study. The inheritance of this character from the Mendelian standpoint has not yet been adequately studied. But as with eye-colour, so with nose-form, we desire to know not only how alternative characters are inherited among individuals of the same race, but how they aretransmitted amongthe offspring of mixed races.

ENGLISH V. GIPSY.

K 1

I am able in the photograph exhibited to show what appears to be an undoubted transmission of a very prominent form of nose from a grandmother to a grandson. The grandmother (on the right of the photograph, who is now over 80 years of age) was the wife of a gipsy and she herself came of gipsy stock. She and her husband eventually settled in a small village in the West of England. They had six children, namely, two sons and four daughters. Of the two sons, one was fair in complexion and had the "wild ways and habits of the gipsy." The other was dark in complexion and married an English countrywoman of the district in which his parents had settled. She was of fair complexion. They are shown, as husband and wife, in the left-hand corner of the central photograph. They have had four children, namely, three girls (shown in the centre of the photograph) and one son (shown standing by the right of his gipsy grandmother in the right corner of the photograph).

The gipsy grandmother has a very prominent type of nose. It is characterised by three chief features: First, the broad base onwhich the external narial apertures are lodged; second, the marked convexity of the contour of the bridge; third, the well-defined or sharp angularity of the general form. Her son's nose differs from hers in all three of these points. His wife's nose is of the more rounded type and differs very widely from that of the gipsy grandmother (her mother-in-law). The three girl children of these two parents clearly do not possess a nose like that of their grandmother. The two younger daughters appear to resemble their mother, while the oldest appears to be an intermediate between her mother and father. So far then there is no feature of any special interest.

But it is otherwise when we come to deal with the nose of the son (grandson of the old gipsy woman). For it resembles hers in all three of the marked features which give to her nose its distinctive and prominent form. The convexity of the bridge is, perhaps, not quite so pronounced, but then he is still young, and this is a feature likely to become accentuated with age.

Two features of Mendelian interest are shown in this group of a grandmother, two parents and four grandchildren. First, there is a hereditary transmission of nose type from grandmother to grandson. Second, there is a clean segregation of the nose type manifested by the brother, from the contrasted nose type or types exemplified by his three sisters. In addition, the case is interesting since it manifests segregation of characters in the offspring of parents of different races,i.e., a gipsy and a native of the West of England.

In the absence of precise information concerning the form of nose of the gipsy grandmother's husband, and of their five other children, and of the brothers and sisters of the grandmother, it is difficult to formulate a scheme showing a definite Mendelian inheritance in this case. But the two features alluded to in the preceding paragraph are strongly suggestive of inheritance according to Mendelian principles.

We are indebted to Mrs. Rose Haig Thomas for the general facts of this case and for the photograph of the group.

EUROPEAN V. AMERICAN RED INDIAN.

K 2

A few years ago I had an opportunity of meeting two friends who had spent many years in different parts of Canada and were acquainted with families who were derived from an ancestry partly European and partly North American Indian. I gathered from my friends, in virtue of much kindness and patience upon their part, some valuable facts concerning the nature of various facial features in the offspring of the two mixed races—European and Red Indian. I purpose here to deal with two families and with only one character,i.e., the type of nose. The Red Indian and European type of nose are easily distinguishable. In the Red Indian the nose is prominent and its frontal profile is formed by two lines which diverge from the bridge towards the base. The latter is, in consequence, very broad. The form of nose is sometimes known as thebusquéor curved type, since its lateral profile is in outline markedly aquiline. But examination of a series of photographs of Red Indians shows some variation in the lateral profile, since some are decidedly concave. But the broadness at the base is apparently never diminished; it is always marked and unmistakable. The well-pronounced Indian nose can always be easily distinguished from the European nose by persons who have had a long acquaintance with both races. But cases do occur where even an experienced observer would feel some doubt in expressing an opinion as to which type a given nose belonged. Such cases are, however, not common.

K 2a

From the pedigrees of families derived from a mixed racial parentage in my possession, I select two for exhibition at this Congress. The first is that known as "Family 5" in my list. In this case a Scotchman (Generation A, S) married a full-blood Indian woman. They had a son and daughter (Generation B, 2 and 3). The half-breed son had the Indian type of nose. The daughter had a small and well-shaped European nose.

The son married a full-blood Indian woman (Generation B, 1) and had four children. Two of these were infants at the time my informant knew them, and though they were described as being generally of the Indian type, they were too young to give any reliable details concerning the form of the nose. The two elder children (Generation C, 1 and 2) were a daughter and a son, and both had the Indian type of nose.

The half-breed daughter (Generation B, 4) married twice. Her first husband was a half-breed Indian (B 3). He was not seen by my informant. They had a son and a daughter (Generation C, 5 and 6). The former was Indian in type of nose as well as in other facial characters. The daughter, though she had very decided Indian cheek bones, had the European type of nose. She is of further interest, inasmuch as while her eye-colour was European the shape of her eyes was characteristically Indian.

The second husband of the half-breed daughter was a Welshman (Generation B, W). By him she had seven children. The last was a baby at the time my informant saw it, and we may leave it out of account. The penultimate child was a son (Generation C, 12), and his nose was sunken, and my informant found it difficult to say whether it was European or Indian in type. I rather suspect from an inspection of some photographs of Indians which I have seenthat it resembles a very concave flattened Indian type. Of the remaining five children, four had an European type and one an Indian type of nose.

Assuming that my informant's observations and memory are accurate—and I feel sure they are quite reliable since he spent many years among the Indians and half-breeds of North America in company with other Europeans, and he is a man of naturally sharp discernment—this family shows clear evidence of the segregation of nose type. It is shown more particularly in the children of the half-breed daughter who married twice, since among her offspring (Generation C, 5-13) both types of nose appeared. The re-appearance of the European nose was manifested, not only when she was mated back to an European in her second marriage, but when she married a half-breed like herself. This latter marriage, however, did not constitute, as we might at first sight regard it, an experimental mating in every way analogous to a Mendelian cross of DR x DR; because although she was a half-breed her nose was not like her brother's of the Indian type, but European.

It thus appears as though the Indian nose was dominant in one case, and the European in the other. Too much stress must not be laid on this point. So many half-breeds are indistinguishable from full-blood Indians, that the possibility is to be borne in mind that this woman's mother, who was married to the Scotchman, was not really a full-blood Indian, and that tradition was in error. I am, however, making further inquiries.

But Mendelian segregation is shown in this pedigree in another way. The granddaughter (Generation C, 6), by the first husband, manifested, as already indicated, an European type of nose and European eye-colour. She also manifested other European characters, with which I do not now purpose dealing. But her cheek bones were decidedly Indian and the shape of her eyes were also Indian. Thus we have the segregation in the same individual of the characters of two distinct races of men. In other words, there has been segregation of racial characters followed by their recombination in a hybrid race. That is a fact of some importance, in what we may designate as anthropological Eugenics, or, if we prefer it, as the Eugenics of Anthropology. For it turns our thoughts to the possibility of calling into being a more perfect type of men by the recombination of the better alternative qualities of two less perfect races.

K 2b

The second pedigree exhibited is that of "Family 4" in my list. I am indebted to another informant for the facts of this pedigree, and they relate to another part of North America. In this case a Frenchman (Generation A, F) married a full-blood IndianPrincess, namely, a daughter of a Chief. She had one only daughter (Generation B, 2) whose nose was of the Indian type, but rather flat.

The daughter married an Irishman (Generation B, 1), and they had six children. Of these three had European types of nose and three the Indian type (Generation C, 1-6).

This family shows again an apparently clean segregation of Indian and European types of nose. The two types appear, side by side, in different individuals of the same fraternity.

THE SEGREGATION OF RACIAL EYE-COLOUR.

ByGeo. P. Mudge.

It is a matter of importance to know the exact influence which a mixture of races exerts upon the hereditary transmission of characters. For instance, do the alternative characters of two races of men, when they are related by marriage, segregate in inheritance in accordance with Mendelian principles? Is the term "blending or fusion of races misleading, and only accurate when employed in a qualified sense"?

It has been shown by Mr. Hurst's very careful investigations in a Leicestershire village that certain types of human eye-colour, which he designates as "Simplex" and "Duplex," are inherited in complete accord with Mendelian principles of inheritance. The two types not only segregate from each other in the course of transmission, but they do so in practically exact Mendelian proportions. And the "Simplex" type, which is the recessive form of eye-colour, breeds true. It begets nothing but the Simplex eye. These results have been confirmed by Professor and Mrs. Davenport in America. In this and similar cases we are merely dealing with the transmission of alternative characters in individuals of the same race.[D]

[D]Of course, the "English" race is really a community of many commingled races. But from our present standpoint that matters little. It is rather confirmatory of the further facts and conclusions I am about to describe.

But one of the interesting problems of the future is concerned with the transmission of characters when human races of diverse characteristics breed together. We are not concerned to discuss now whether the races of mankind are varieties or species.

K 3

SPANIARDv.GIPSY.

The records of travellers provide certain information which helps us to form reliable though limited conclusions as to the results of theinterbreeding of different human races. Mrs. Rose Haig Thomas,to whom we are indebted for the exhibit of a photograph, taken during a journey through Spain a few years ago, of a Spanish gipsy woman with her three children, has made several observations of some interest. She became acquainted with a family in which "the mother was a dark-skinned, black-haired, black-eyed gipsy woman. (See photograph, Exhibit No. K 3.) The husband was a Spaniard with blue eyes. There were three children. Of these, the eldest had flaxen hair and blue eyes. The second was a boy with black eyes, black hair, and an olive skin as dark as the mother's. The third child was too young to justify any conclusion being based on its characteristics. It was only 18 months old; but was flaxen-haired, blue-eyed, and fair skinned." This observation of Mrs. Haig Thomas, in Granada, affords then a clear example of the segregation of blue-eye and flaxen-hair characters among the gametes of the black-eyed, black-haired, and olive-complexioned mother. For, in the light of Mendelian researches, it is obvious she was carrying these characters recessive, and that some of her gametes were pure in respect of them.

ARABv.SPANIARD.

K 4

The second photograph, exhibited by Mrs. Haig Thomas (Exhibit No. K 4), is of three sisters who were also photographed in Granada. The eldest is of the dark, typical "Arab type," so well recognised by Spaniards wherever it is seen in Spain. The second sister is clearly much lighter in hair and fairer in complexion than her sister. The nose, too, is very distinct in both. The baby is fair. It is impossible, of course, to trace the remote ancestry of these sisters, and Mrs. Haig Thomas obtained no information as to their parents, but from what we know of Spanish history the case suggests apossible segregation of Moorish from Gothic featuresafter the intermixture of the two races, by marriage, had occurred. But the question is extremely complex. It is impossible to say to what extent the inhabitants of modern Spain represent in varying degrees a commingled race of Phœnicians and Iberians, of these with Romans and Goths, and of all with Moors, themselves at the time of the conquest of Spain a mixed race. All that can be said with any degree of probability is that these various races have more or less intermingled[E]during the long history of Spain, and that the flaxen hair and blue eyes among its inhabitants are the heritage which the Goths have left them.

[E]I advisedly use the word intermingled and not blended.

EUROPEANv.AMERICAN RED INDIAN.

For the facts of the segregation of European and Indian eye-colour, I am indebted to two friends who resided for many years in different parts of Canada, and who do not desire their names published.

K 5

The first case of this kind (Pedigree Chart, No. K 5) ofsegregation of racial eye-colouris that of the offspring from a marriage between a blue-eyed Scotchman and a black-eyed, full blood American Red Indian woman.[F]They had a son and a daughter, and the eyes of both were Indian brown. This brown differs from that of European eyes, and can usually be distinguished by observers who know the two races well. The half-breed son (No. 2, Generation B) married a full blood Indian woman (No. 1), who also had Indian brown eyes, and by her had four children. Two of them were babies at the time my informant knew them, and we may leave them out of account. The other two, a son and daughter (Nos. 2 and 1, Generation C), had Indian brown eyes. This result is in accord with Mendelian expectations.

[F]This is the same family as Family 5 described in connection with Segregation of Nose Form in exhibit K 2a.

The half-breed Indian daughter (No. 4, Generation B) of the blue-eyed Scotchman and Indian mother married a Welshman (No. 5, B) with hazel eyes. They had seven children. Of these, two—a son and daughter (No. 7 and 11, Generation C)—had blue eyes. The remaining children—with the exception of a baby, whom my informant had seldom seen—had eyes of varying shades of brown. Two (Nos. 9 and 12, C) had European brown, one dark Indian brown, and one Indian brown eyes (Nos. 8 and 10, C).

The re-appearance of blue eyes among two of the Scotchman's grandchildren is a clear example of the Mendelian segregation among the gametes of the half-breed Indian mother of the factors which produce blue eyes. The Welsh father, with the hazel eyes, must, of course, as we deduce from other cases, have carried the blue-eye factors recessive.

The black-eyed full blood Indian grandmother also carried various shades of Indian brown, recessive to the Indian black which she herself manifested, since her daughter and two granddaughters exhibited Indian brown and dark Indian brown coloured eyes. The two European brown-eyed grandsons were probably in eye-colour hybrids between the hazel colour of the Welsh father and the Indian brown of the half-breed Indian mother.

The pedigree is thus, in respect of eye-colour—and of other characters also which are not here described—clearly Mendelian in its manifestations. It shows that the offspring of two very different types of human races exhibit the same mode of Mendelian inheritance as do the descendants of two contrasted parents of the same race.

K 6

Family 4 (Pedigree Chart, No. K 6) illustrates the same kind of facts and conclusions. In the A Generation a Frenchman, whose eye-colour was unknown to my informant, married a full blood Indian princess who had Indian brown eyes. There was one daughter only (Generation B) by this marriage, and she had Indian brown eyes. She married an Irishman, who had red hair, grey eyes, and a freckled complexion (Generation B). From this marriage there came six children (Generation C). Two of these had "grey eyes like their father." Three had dark brown eyes of European tint. My informant had some doubt as to the European tint of two of these three (Nos. 3 and 4, C Generation); their eye-colour was very dark brown, and possibly it may have been the Indian tint. The remaining member of this generation had Indian brown eyes of a very dark shade.

It may be desirable to state that Families 4 and 5 come from different parts of Canada.

The chief feature of interest in this family is the segregation of the grey eye-colour of the Irishman among his offspring. It appears in two daughters. From what we know of analogous cases, there is little doubt that the gametes of his half-breed Indian wife carried the blue or grey factors derived from her French father. The appearance of an European brown eye-colour in Generation C, No. 6, suggests that the French grandfather had brown eyes, and that, therefore, this colour has segregated out among the gametes of the half-breed Indian mother.

Exhibited by Mr. E. Nettleship.

L 1

Congenital Colour-blindness. Pedigree showing unusual features, viz.: (a) females affected; (b) twins, of whom one is affected, the other not; (c) marriage between two unrelated colour-blind stocks. Except that two females are affected the inheritance, so far as can be traced, has followed the rule for colour-blindness; viz., limitation to males and transmission through unaffected females.

L 2

Hereditary night-blindness with myopia(short sight) affecting 21 males and only 1 female in a large pedigree. The night-blindness congenital and stationary. Descent always through mothers themselves unaffected. Mental defects in several of the night-blind stock. Other pedigrees of this male-limited night-blindness are on record.

Key.andnight-blind male and female. Otherwise the same as for L 1.

L 3

Pedigrees ofhereditary congenital Nystagmus(involuntary rhythmical movements of the eyes) showing two different modes of descent.

L 3a

In Figure L 3a the nystagmus occurs only in males and descends through unaffected females.

L 3b

In Fig. L 3b both males and females are liable to the disease, and either parent may transmit it, although descent is more often through mother than father.

The movements of the eyes are very often accompanied by rhythmical movements of the head in the non-sex-limited type (Fig. L 3b), but head movements very seldom occur in the male-limited type (Fig. L 3a).

In both types many of those affected have also optical defects of the eyes, especially astigmatism. No mental or nerve complications in either kind.

Key.andmale and female with Nystagmus. Otherwise as for L 1.

L 4

Pedigree ofhereditary Cataract. The cataract in this genealogy begins in childhood, and usually progresses so as to require operation by the time its subject is grown up; results of operation usually good and lasting. Most of the affected members still living; of the fourdead, none died before 54, and two of them lived to 78 and 83 respectively. Both sexes affected and either sex may transmit. No other eye disease and no prevalent constitutional diseases or degeneracies in the cataractous stock.

Many similar pedigrees are known.Key.andmale and female with cataract. Otherwise as for L 1.

Exhibited by Professor R. C. Punnett, F.R.S.

Mendelian Inheritance in Rabbits.

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