By dosing the serum-cholesterol in basal conditions in 5 0 MZ (25 ♂ ♂ and 25 ♀ ♀) and 50 DZ (16 ♂ ♂ 18 ♀ ♀ and 16 ♂ ♀ ) twin-pairs, the Authors found an intra-pair dissimilarity significantly different among the pairs of the two zygosity groups. On this basis, the genotypic origin of cholesterol biogenesis is pointed out. The twins, aged from 6 to 19, were all living with their respective families: nutrition and environment were thus the same for each pair.

Après le discours d'introduction du Prof. Robert Montant, Doyen de la Faculté de Médecine, le Prof. Klein remercia les autorités et présenta ses hommages au Recteur, au Collège des Professeurs, en particulier à son maître, le Prof. A. Franceschctti. Il s'adressa ensuite aux étudiants et à l'auditoire en ces termes:

Messieurs les Etudiants,

Quelques-uns d'entre vous se demanderont peut-être où réside la nécessité d'introduire dans le programme clinique déjà si chargé une nouvelle spécialité, la génétique humaine, d'autant plus qu'elle a déjà la réputation d'être une science théorique pure et dépourvue d'intérêt thérapeutique.

Laissez-moi vous dire que la génétique humaine n'est pas une spécialité sui generis dans le même sens que les autres branches de la médecine. En effet, dans la hiérarchie des sciences médicales elle joue en quelque sorte « l'officier de liaison » dégageant de chaque discipline les données héréditaires et rassemblant ces éléments pour en faire une synthèse. Le généticien est donc plutôt un spécialiste malgré lui puisqu'il doit former un tout homogène des résultats si vastes et si divers obtenus dans les divers domaines des sciences biologiques et médicales. Pascal, sans le savoir, a très bien caractérisé la situation du généticien qui doit conserver une curiosité générale et tirer son matériel de toutes les sciences de la vie, lorsqu'il dit: « Puisqu'on ne peut être universel en sachant tout ce qui peut se savoir sur tout, il faut savoir peu de tout. Car il est bien plus beau de savoir quelque chose de tout que de savoir tout d'une chose ».

In continuation of the series of studies of racial crosses, this paper gives a genctical account of various race hybrids, in which Australian aborigines or Papuans are involved with Chinese, Malayans or Filipinos. Several families are traced through four or five generations, and some involve three or (in one case) four different races. Most of these racial combinations have not been studied previously.

The racial characters recorded in Tables include colour of eyes, hair, eyebrows, eyelashes and skin, form of hair and measurements of head and of ears. In addition various observations of brow ridges, orbits, eyefolds, nose, lips and mouth were made. The Mongolian brachycephaly is strongly inherited from male Chinese ancestors; also the eyefolds, especially the top fold, which is more or less independent of the epicanthic fold. In Malay crosses the face and head are often very narrow. Marked segregation in sibs can occur in head form (cephalic index), hair colour, hair form, skin colour and other features. It has already been shown that in the F1 of aborigines × White the skin is near white. The same is true of Papuan × White, and in addition the child's hair is flaxen or very light brown although the Papuans appear to have always black or near-black hair.

Incidentally, it was also observed that the Papuans not infrequently have marked brow ridges, depressed nasal root and sunken orbits like the Australian aborigines, indicating common elements in the ancestry of these two races.

The Papuan nose, commonly with an overhanging tip, differs in some respects from the Semitic nose, and appears to be an independent (parallel) development.

All contrasted human racial characters, such as hair form and colour, head shape, brow ridges, nasal root depression, size of ear and of mouth appear to depend on a small number of cumulative genes, generally without dominance. In how far these are alleles or based on genes at independent loci can only be determined by further investigations.

The Author reports on the simultaneous appearance of a skin manifestation of the B.B.S. disease in female Twins. Partly diffuse and partly nodose infiltrations, with tendency to peripheral extension and central resolution constituted the clinical picture of the disease: (diffuse, small nodose variety of Boeck's sarcoids). In both cases the localisation was on the right cheek, the time-course was very similar. The histological picture was almost identical and was represented by infiltrations of epiteloid-cells with concentrical distribution.

The Author reports on the striking frequency of marked hereditary pathologic anomalies in the family of a proposita suffering from Biemond's Syndrome (diencephalic obesity, debility, neurologic and mental disorders, endocrine troubles, syndactyly of the feet and bilateral coloboma of the iris).

In the 173 membres of the family (non including the proposita) the Author found 17 cases of unilateral or bilateral coloboma (6 of whom died blind), 4 cases of iris malformation with atrophy of the stroma, 4 cases of females with serious unilateral or bilateral malformation of the hip-joint, 1 uncertain case of a male with Perthes disease, 4 cases of epilepsy (included a concordant MZ twin-pair), 1 case of a male suffering at the same time from imbecility and underdevelopment, 1 case of a female affected by coloboma, arachnoidal cyst and epileptic convulsions, and, further, some cases of myopia, single cases of strabismus, hyphoscoliosis, lipomatosis, hemolytic icterus and 1 case of a still-born child with atresia recti and hypoplasia of one arm. Besides a case of suicide, some members of the family are supposed to have been somehow « queer ».

It is probable that a degree of linkage exists between the genes for coloboma and epilepsy. All other findings, for the moment, may only be recorded. In order to reach some final conclusions other family studies will have to be added to the present one.

Three families from Calabria, whose members were related to each other have been studied. In the first there were both the thalas-semic and the drepanocytic traits separately in its members; in the second the thalassemic trait and in the third the drepanocytic trait. From the marriage of individuals with thalassemic trait from the first and the second family a child was born with Cooley's disease, from the marriage of drepanocytic individuals from the first and the third family a drepanocytic girl was born.

The clinical, hematologic and genetic characteristics of the 19 members of these families are reported and the distribution of the pathologic features is discussed.

The Authors have reported five twin-pairs, two of which DZ and three MZ, all affected by poliomyelitic paralysis, affirming the existence of a particular predisposition to this disease and even of a local predisposition in MZ pairs.

The M quadruplets have been regarded as monozygotic by all investigators who have studied them carefully. Previous authors have based their diagnosis on the description of the placenta, on early physical resemblances, and on qualitative features.

The addition of blood group tests to the criteria now tends to confirm the earlier conclusion. From an extension of methods devised for use in twins, it appears that the probability that these quadruplets originated from more than one zygote is less than one per cent. However, some quantitative differences, especially in finger prints, require a more elaborate analysis, and such an analysis will be presented and discussed in a second article.

The Authors confirm the finding of a difference in the diameter of the nuclei of myelocytes between males and females.

The diameter is greater in the females, with a significance of 1‰ (Student's t).

In cases of myelocytic leukemia the difference is even greater, suggesting the hypothesis that in this disease the cells may be polyploid.