170 HEREDITy AND SELECTION IN SOCIOLOGY 



never alone, but ia always the expression of a pathological variation 

 affecting the whole germ-plasm, may be transmitted, especially if its bearer 

 unite with another individual whose germ-plasm is likewise in a state of 

 pathological degeneracy. 



6. The teratologioal malformation which accompanies a pathological 

 condition of the germ is transmitted only for three or four generations ; the 

 family finally succumbs to sterility. 



7. Those cases of dissimilar heredity, in which the malformation affects 

 in the offspring a different organ from that which is affected in the parent, 

 confirm the hjrpothesis that the teratological determinants simply form 

 part of a general pathological variation. In the relations between the 

 difi^erent groups of morbid determinants it is quite possible that now one 

 pathological group, and now another, should gain sufficient strength to be 

 able to manifest itself teratologically. 



With regard to the action of alcoholism, which is often accompanied by 

 teratological stigmata, it is possible that these stigmata are not always of 

 a hereditary, but only of a congenital nature. Experimental teratology 

 has demonstrated the great influence which even the smallest injection of 

 alcohol may have on the egg, in causing profound nutritive troubles. As 

 teratological characters resolve themselves into troubles of the nutritive 

 system, we may suppose that the alcoholic mother exercises a similar influ- 

 ence on the embryo ; and that she brings to the embryo a bad nutrition, 

 which causes teratological malformations. 



The fact that it is the constitutional condition of the organism which 

 is the important point is again confirmed by the difference with which the 

 same dose of poison may react on a healthy organism on the one hand, 

 and on a more susceptible one on the other ; producing no result in the one 

 case, and determining in the other anatomical injuries. As a matter of 

 fact, the part played by the neuropathic predisposition is recognised to-day 

 in the case of a great many maladies, such as infantile paralysis, which 

 were formerly regarded as independent nosological entities. 



The question to-day is, as we have seen. Does there exist a disease which 

 is a nosological entity 1 The rdle of morbid predisposition of a neuropathic 

 nature in so many diseases formerly considered as independent, such as 

 tuberculosis, syphilis, and even certain of the microbic infections, such as 

 typhoid fever, is calculated to throw great doubt on the existence of 

 discrete independent diseases. At all events, we may conclude that, as 

 far as teratological heredity is concerned, there is nothing in the facts 

 known to medical science incompatible with the theory of heredity and 

 evolution as Weismann has expounded it. 



