This study is based on pedigrees of 192 patients with rheumatoid arthritis which are compared with pedigrees of 300 controls.

6,3 per cent of all relatives in the first group had rheumatoid arthritis compared to 0,38 per cent of all relatives in the control group. An hereditary predisposition to rheumatoid arthritis is definitevely to be admitted.

This predisposition is due to the presence of a principal autosomal dominant gene with reduced penetrance and variable expressivity. It seems to have no genetic relationship to the diathesis of allergic diseases and the diathesis of degenerative connective tissue disorders (mesenchymotic diathesis).

The Authors refer the results of a genetical, clinical and statistical research on a group of 265 patients with cancer of the prostate. The data show a significant familiar incidence only for the cancer of the same site.

1. There is probably no special hereditary disposition for the localisation of the tuberculosis at the skin.

2. The partial selection of the hitherto made casuistics of twins explains the contradiction to the literature.

3. The general tuberculosis is in the sense of Diehl and v. Verschuer preponderating concordant by monozygotics twins and discordant by bizygotics twins.

The Klippel-Trénaunay-Parkes Weber-syndrome (K.T.W.) is a congenital malformation with partial gigantism (osteohypertrophy), naevi and varicose veins in the fully developed trias of symptoms. According to arterio- and phlebographic findings varicose veins are usually the result of mal-and deformations of the deep venous system or arteriovenous anastomosis, rarely of the arterial system alone.

In a critical consideration of all hypotheses about aetiology and pathogenesis of the K.T.W.-syndrome is discussed that there is no satisfactory explanation for the assumption that the syndrome is a exogenous malformation.

It is pointed out that so far there have been no family investigation of a greater extent. The statistic survey of the existing family investigations showes that the K.T.W.-syndrome is most variable in its phaenotypical manifestation and also has a strong intra-and interfamiliar variability. Heredopathologically is suggested that apart from a weak (?) principal gene secondary genes are essential for the manifestation. The mode of inheritance may be either dominant or recessive. The existence of various biotypes is considered probable. It is proposed to count the K.T.W.-syndrome into the group of the ectome-sodermal malformations (Oehler), the hamartomata (Wohlwill), the phacomatoses (van der Hoewe) or the neuro-cutaneous syndromes. 2 own cases are described.

Wiener's methods for estimating gene frequencies from MNS data are compared with the maximum likelihood methods, and found not to be fully efficient. The extra effort and expense which would result from the use of such methods is discussed. It is concluded also that the number of significant figures advised by Wiener is not sufficient.

In this paper an unselected series of 19 twins with migraine is reported. The findings in 13 pairs with ascertained twin diagnosis, 3 MZ and 10 DZ, are preliminarily summarized. With regard to typical migraine, only 1 MZ pair was concordant, a minor degree, of concordance was seen with all MZ and 3 DZ pairs. Regarding a distinct picture of vegetative dystonia, all MZ and 2 DZ pairs were concordant. On the basis of these results it can be assumed that various etiological factors are responsible for the manifestation of hemicrania. The hereditary basis seems to lie in a vegetative, diencephalic, dysregulation. Besides, the clinical manifestion is determinated by various preformative influences of an endogenous or exogenous nature.