3o8 NATURAL SCIENCE. May. 1897. 



infection he is more resistant to the disease, ^.^.,in that he more easily 

 attains immunity, and does not so readily perish. Mr. Buckman 

 thinks that this evolution of resisting power " looks remarkably like 

 inheritance of acquired characters." But, if acquired powers of 

 resisting are transmissible, acquired weaknesses should also be 

 transmissible. And, therefore, in the case of such diseases as tuber- 

 culosis and malaria (against which immunity cannot be acquired, 

 and of which one attack predisposes to subsequent attacks), races, 

 long afflicted by them, should be much less resistant than races that 

 have had little or no experience of them. The contrary however is 

 true, for the negro is more resistant to malaria, and much less resistant 

 to tuberculosis than the Englishman. In this case, therefore, acquired 

 immunity can have played no part. 



Again, indulgence in certain narcotics increases the craving for 

 them ; and some of these narcotics {e.g., alcohol and opium) are the 

 cause of a vast number of deaths. If, then, acquired traits are trans- 

 missible, a race that has long used a powerful narcotic should crave 

 more for excessive indulgence in it than a race that has had but a 

 short acquaintance with it ; on the other hand if acquired traits are 

 not transmissible, then the elimination of individuals with a great 

 craving would render the former race less liable to excessive indulg- 

 ence than the latter. Now the evidence is overwhelming that races 

 that have longest used a powerful narcotic are invariably those that 

 are least inclined to excessive indulgence in it. Here then is another 

 great series of physiological experiments proving, just as disease 

 proves with regard to acquired physical traits, that acquired mental 

 traits are not transmissible. 



We must conclude, therefore, that since the great causes of 

 elimination are not very numerous, man's present evolution cannot 

 be very complex ; and, therefore, since I have dealt with all the great 

 causes of elimination, that I am justified in my claim that my work 

 really does cover the whole ground. 



G. Archdall Reid. 



Netherby, Victoria Road South, Southsea. . 



