332 THE POPULAR SCIENCE MONTHLY 



dren. Now the interpretation of this result is not simple ; in part the 

 higher death rate of the negro is due to economic conditions that are, 

 however, determined largely by racial traits ; but, in part, it is probably 

 due to the fact that the negro is not yet adjusted to the white man's 

 civilization. Especially does this folk of jungle origin wither away in our 

 large cities. Similarly, the death rate from tuberculosis is 3 times as 

 great among our Indians as among the whites, and deaths from measles 

 are proportionally greater among Indians than whites. Clearly the 

 grand races differ tremendously in their vitality. 



I know there are those who deny that there is such a thing as in- 

 herited resistance to disease. But there is at least a family liability to 

 or immunity from various diseases, such as tuberculosis. It is easy to 

 find in our records families in which 10 out of 12 or 14 deaths in a 

 family have been from tuberculosis; as it is easy to find families of 

 which none of the 10 or more members who have died have died of this 

 disease, even when they have died at mature age, and, like practically 

 every person, exposed to the disease. I think, then, we must recog- 

 nize that non-resistance to tuberculosis is a family trait; and it may be 

 characteristic of a whole locality, provided that locality (like southern 

 California) has attracted many representatives of the non-immune race. 

 We find indeed that, despite its salubrious climate, consumption is a 

 much more common cause of death here than in most other sections of 

 the country; and the high incidence of tuberculosis is found in the 

 children and grandchildren of those who went to California for their 

 health. 



Again cancer is a disease whose rate of incidence varies in different 

 parts of the country ; it is highest in the state of Maine. Now, I have 

 no doubt that this is due to the presence of one or more races in Maine 

 which are non-immune to cancer. I know that many medical men do 

 not respond favorably to the contention that there is a racial cancer 

 diathesis in man. To be sure, it has been repeatedly demonstrated that 

 such races occur in mice and such human families as we have studied 

 yield the same result as the mice studied and indicate that resistance 

 to cancer is a positive (dominant) trait and that non-resistance appears 

 in the children only when both parents belong to a non-resistant race. 

 And this result is commonest, other things being equal, where cousin 

 marriages are commonest, because that makes it probable that if one 

 parent belongs to a cancer race the other — the cousin — will belong to 

 the same cancer race. Now in rural Maine, cousin marriages are ex- 

 tremely frequent — especially in the islands off the coast, and here we 

 have the conditions for the result — the high incidence of numbers of 

 the cancer race in an inbred community. 



Again Huntington's chorea is a fairly common cause of death in 

 certain localities, and it is a racial character as truly as are brown eyes. 



