DR ARCHDALL REID'S book on Ike Laws oj Here- 

 dity (Methuen & Co.: London. 1910. 2is.) is enor- 

 mously long and uncompromisingly stiff, yet it does not 

 seem to help us very materially in coming to a conclusion 

 on the laws with which it deals. Unquestionably the 

 most interesting and the most novel portion of the book 

 is that which deals with the relation of modern views 

 as to the role of bacteria in disease with the question of 

 Natural Selection. That they are a potent agent in 

 selection no one can doubt and if anyone does Dr Reid's 

 pages may be commended to his attention. That there 

 are other selective agencies at work no person can doubt 

 who examines the facts of Nature and existence for him- 

 self with open eyes. But what we have always maintained 

 is that having got so far upon the road and having con- 

 ceded, if you like, that Natural Selection exists which 

 all scientific men do not concede and that it is a potent 

 sieve if a sieve can be called potent that even then 

 we have only started upon the path at the end of which 

 lies the explanation of variation and of .inheritance 

 That variations occur everybody knows, that Natural 

 Selection may tend to perpetuate or to eliminate them 

 we may admit, but what causes the variations to appear ? 

 That is the real heart of the question. The Lamarckians 

 have an answer which is at any rate arguable. Dr Reid 

 will have none of it, and in our opinion rather underrates 

 the influence of Lamarckian opinion at the present day. 

 Weismann also had or has an answer, but his solution of 

 the difficulty only pushes the question one stage further 

 back and leaves it there unanswered. Until some solution 

 of that mystery has been arrived at, if indeed it ever is 

 arrived at or is arrivable at, we may learn what laws 

 govern heredity, if one may still be allowed to use the" 

 misleading nomenclature generally applied to what are 

 called Natural Laws, one may come to a conclusion as 

 to Mendel and his views or de Vries and his, but we shall 

 remain all the time on the threshold only and not within 

 the recesses of the temple of Nature's secrets. 



i ' B.C.A.W. 



