PHENOMENA OF INFECTION. 77 



was visited upon them. But the dispassionate reason- 

 ing of scientific investigation has acquitted them of 

 those charges by explaining their insusceptibihty to 

 infection as a pecuharity of the Hebrew race. Thus, 

 by far, fewer Jews are victims of pulmonary tubercu- 

 losis than Gentiles, and Asiatic cholera is so rare among 

 them as to lead some authors to doubt that it ever 

 occurs. Furthermore, they suffer less severely from 

 other infections, and less from animal parasites, than 

 other races. However, it must be confessed that in the 

 case of the Jews (and in that of any other race, for that 

 matter), racial characteristics do not explain entirely 

 the absence of predisposition. We should err greatly 

 did we fail to take into account a race's habits and 

 customs. For instance, other things equal, the Jews 

 are better housed, 'eat more wholesome food, are more 

 cleanly in their habits; take better care of their children, 

 and are less given * to intoxicants, than their Gentile 

 neighbors ; while all of them are still" influenced more or 

 less by thfe Mosaic laws. Their standard of life, if 

 adopted by any people," would tend to strengthen its 

 vital resistance and, in some at least, would lead to 

 the establishment of the antithesis of predisposition, 

 namely, immunity. 



Another factor which exercises its influence upon a 

 race's susceptibility, or immunity, is the length of time 

 it has been in contact with a disease. The first con- 

 flict of a race with an infectious disease often proves 



