The Authors have analyzed the separate and combined influences of zygosity, placentation and sex on intra-pair birth-weight differences in 124 MZ and 124 DZ twin pairs. The highest influence on birth weight was found to be due separately to zygosity and placentation (respectively in cases of dizygosity and of a single placenta). The single placenta causes more circulatory unbalance and, as a consequence, more intrapair weight difference. This finding may help to explain the higher frequency of blighted fetuses in utero in MZ twin pregnancies and that of discordant congenital heart disease in female MZ twins.

The Author reports on six subjects of a family (three generations) affected by congenital atresia of the lacrimal canaliculi.

Endocrinology more than any other medical specialty requires consideration and cooperation of genetics. History of the rapid progress of clinical endocrinology in the last 50 years shows that human genetics has been lagging far behind endocrinology in clinical medicine. The psychologic reason seems to be the mechanistic trend of modern medicine and reluctance to use abstract logical thinking applied to material facts.

When calculating the chance of monozygosis from the results of a blood group study in a twin-family, it is desirable to use the complete information that is presented by these results and not only part of it.

A calculation-method in which the complete genetic-information is used is presented.

The use of the formulas is demonstrated by calculating the probability of monozygosis in two examples.

Our study on a kindred of spoon nails found among residents in Wakayama City, shows:

1. The kindred includes 36 affected members extending in five generations (Fig. 1). The seventeen marriages between affected and normal members of the kindred and which have more than two children, produced 29 affected, 16 males and 13 females, and 37 normal children 22 males and 15 females. This 37: 29 ratio falls within the range of the 1: 1 ratio of the affected and normal offspring. The sex ratio of the affected members, 16 males: 13 females, also is about 1:1. Thus, the abnormality seems to be due to a single autosomal dominant gene.

2. The penetrance of the gene in this family is apparently fairly high.

3. Regarding the expressivity of this abnormality, the concavity of nails is not always distinct especially in toes, while the expressivity of the gene in finger nails is more apparent.

The literature and results of studies on the subject of lateral dominance have been reviewed and discussed, and pertinent hypotheses advanced. The various known facts need not be considered contradictory if multiple genetic factors are hypothesized, interacting with an ontogenetic predisposition to left cerebral (and right somatic) dominance, and with various psychological-social factors.

Eight sweet tasters for P. T. G. found in a preceding investigation were retested with P. T. G. solutions by using a discriminating test method. Variations in the course of a single day and during longer periods were studied. It was observed that the consistency of sweet tasting for this compound varied intraindividually as well as interindividually. One of the females showed a high consistency of taste sensations for different concentrations. Three persons never reported a sweet taste sensation of a supraliminal concentration, although one year earlier they had described different P. T. C. solutions as sweet or sweet and bitter at the same time. The remaining four persons showed a varying consistency of the number of solutions stated as sweet tasting and the concentrations of these sweet tasting solutions. The reasons for the variations of the consistency are unknown. Such inconsistencies influence the result of investigations into inheritance of the trait.

A large Brazilian family, of white ancestry, in which several members presented a spinocerebellar ataxia, was studied. Informations were obtained covering six generations, in a total of 337 related individuals. 116 of them were examined by the author. 18 presented the disease, and of these 10 were alive at the time of the study. Besides them, by her descendents, it was possible to find a carrier of the gene, who died in a preataxic age.

The disease is transmitted by an autosomal dominant gene, and appears at the age of 38.33 ± 1.74 years. Cerebellar, posterior chord and pyramidal alterations were present in the sick persons. Almost all the patients presented disturbances of the temperature sense. The disease had not lowered the viability and fertility of the affected persons.

After a short review of the literature on the subject, the Authors report a personal observation of Cooley's disease in uniovular twins adding some general observations. They conclude by stressing the rarity of this observation.

Vor vierzehn Jahren konnte ich (1) in dieser Zeitschrift zusammenfassend über «Erbbiologische Untersuchungen über die Entstehung der Homosexualität» berichten. Wenn ich nunmehr nochmals auf diese Untersuchungen, die in der Zwischenzeit durch die Berechnung von möglichen Valenzen der geschlechtsbestimmenden Faktoren bei Homosexuellen und deren Eltern ergänzt wurden zurückkomme, so liegt die letzte unmittelbare Veranlassung darin, dass neuere cytologische Untersuchungen prinzipiell die Prämissen, von denen ich bei meinen Untersuchungen ausgegangen bin, bestätigten. Beim derzeitigen Ueberwiegen der psychologischen Literatur auf dem Gebiet der Homosexualitätsforschung schien es dazu schon an und für sich angezeigt, das Problem der Triebumkehr mit Fragen und Ergebnissen der Genetik und Erbbiologie darzustellen.

Die Untersuchungen, die von mir, nachdem sie schon einige Jahre geplant waren, im Jahre 1934 begonnen wurden, nahmen ihren Ausgang von folgenden Ueberle-gungen. Die Homosexualität ist eine ubiquitäre, bei allen Völkern, zu allen Zeiten und in allen Kulturkreisen auftretende Erscheinung, weshalb auch die meisten führenden Psychiater und Sexualforscheres sei nur an E. Kraepelin, A. Forel, E. Bleuler und R. von Krafft-Ebing erinnert stets neben den exogen bedingten Formen von Homosexualität eine Kerngruppe von genuiner, anlagebedingter Triebumkehr annahmen. Wir können also ihre Erklärung mindestens mit derselben Wahrscheinlichkeit wie in psychischen Faktoren in den ebenfalls ubiquitären physiologischen oder pathophysiologischen Vorgängen, die die Anziehung oder Abstossung der Geschlechter bedingen, suchen.