560 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1918. 



is " blended "; in other words, the individual may be looked upon as 

 the result of a mechanical mixture of the germinal material of his 

 two parents. This is, perhaps, best seen in the various shades of 

 skin color (mulatto, quadroon, octoroon) which result from the mat- 

 ing of a white with a negro. In the second group certain qualities 

 or peculiarities of one germ cell seem to dominate over antagonistic 

 qualities of the germ cell of the other sex, so that the individual 

 " takes after " his father in regard to some details, but after his 

 mother in regard to others. As Goethe says: 



Voni Vater hab' ich die Statur, 

 Des Lebens ernstes Fiihren ; 

 Voni Miitterchen die Frohnatur 

 Und Lust zu fabuliren. 



At the same time an individual who himself shows no indication 

 of any parental peculiarity may yet pass it on to his offspring, con- 

 stituting what is described as patency and latency, as is seen in 

 hoemophilia and certain other diseases. It seems likely that what 

 is commonly known as prepotency, dominance, and patency and 

 latency, may be embraced within the laws which were first discovered 

 by Gregor Mendel, Abbot of Briinn, 50 years ago, and which are 

 now known as Mendel's Laws. Mendel's conclusions, drawn from 

 experiments on peas, were long unknown to the world; but their re- 

 discovery has given an enormous impetus to similar inquiries, and 

 during the last few years numerous investigations have been made 

 with the object of ascertaining whether his results are applicable to 

 man. With regard to some qualities this has been shown to be the 

 case; and it now seems to be established that such abnormalities as 

 brachydactyly, color blindness, night blindness, and congenital cata- 

 ract are transmitted in accordance with Mendelian laws. Is this so 

 with the neuropathic diathesis, which we may certainly consider the 

 most important form of degeneracy from the socialogical aspect? 



Researches which have been made under the auspices of the Eu- 

 genics Record Office of America proclaim that this is the case, and 

 that " the fact of the hereditary transmission of the neuropathic con- 

 stitution as a recessive trait, in accordance with the Mendelian theory, 

 may be regarded as definitely established." But the difficulties and 

 sources of possible fallacy attendant upon such inquiries are so great 

 that one must accept these conclusions with considerable reserve. It 

 is impossible to deal adequately with the question in this place, but 

 it may be remarked that a person may be of neuropathic constitution 

 and yet pass through life apparently normal, owing to the absence of 

 any direct excitant to a mental breakdown ; in other words, he may 

 inherit a predisposition to insanity and yet, in consequence of his 

 life being cast amid healthy surroundings devoid of strain, never 



