163 



With regard to problems of genetics the author's usual attitude 

 is that of the professed and altogether convinced Mendelian. 

 The Mendelian principles are supposed to control the heredity 

 of all kinds of characters, though "autogenous fluctuation" is 

 sometimes invoked in extreme cases. Like some of our American 

 Mendelists, our author asserts his convictions the more emphat- 

 ically when the facts seem to be carrying him away from the 

 typical Mendelian points of view, as the following paragraphs 

 will show: 



"The author can only reiterate his conviction that all these 

 hybrids are subject to Mendel's Law of segregation; often ob- 

 scurely — on account of defective methods — but none the less 

 certainly. The evidence available can all be interpreted in 

 Mendelian terms, and it is very significant that most of it should 

 appear at first glance to be completely dissociated from the 

 classical ratios. Mendelian students of heredity have confined 

 themselves to the more definable characters, such as color, 

 partly because statistical characters take up an excessive amount 

 of time in mere determination, and partly because the use of 

 statistical methods is prone to provoke irrelevant criticism from 

 mathematicians with whom the mere biologist cannot fairly 

 compete. At the same time it is clear that the frontier of 

 Mendel's territory is not demarcated by any special character 

 and — with all their experimental disadvantages — the only char- 

 acters which admit of complete treatment are those which can 

 be measured with definable precision. There are many features 

 of these complex results which bear a tantalizing resemblance 

 to problems of human heredity" (p. 132). 



Nor is our author lacking in scientific candor when the time 

 comes for general statements regarding the practical application 

 of Mendelism to the lint characters, and to the other features of 

 the plant that do not lend themselves to direct statistical treat- 

 ment. 



"From what has been said above It will be clear that the 

 'style' of a lint sample is the resultant of an unknown number of 

 unknown factors, both zygotic and gametic. When a set of F2 

 samples is placed before an expert, this becomes obvious; the 



