120 MENDEL : 



work following on them. Suffice it to say that 

 Professor Weldon was of opinion that sufficient 

 attention had not been paid to the ancestry of 

 the forms experimented with ; and here it may be 

 noted that de Vries one of the re-discoverers of 

 the theory is of opinion that Mendel's law of 

 dichotomy only holds in general for phylogeneti- 

 cally recent characters. Those who desire to pursue 

 their investigations further must consult the 

 works placed at the head of this article and others 

 to which they will find themselves referred in the 

 books and papers cited. 



It may, however, be stated that some workers 

 have, in their experiments, been led to the con- 

 clusion that the Mendelian laws are not every- 

 where and in all cases applicable. Thus, to give 

 but two examples, Davenport concludes that 

 " while Mendelian principles seem applicable to 

 some cases of crosses between sports and the 

 normal species, there seem to be others where 

 neither Mendel's nor Galton's Law of Inheritance 

 holds." * 



This conclusion he arrives at from his study of 

 the so-called " wonder-horses." Moreover, his 

 study of colour in mice leads him to think that 

 " Mendel did not discover all the important laws 

 of inheritance " which is more than likely 

 " and that further investigation will unquestion- 

 ably reveal other and still broader principles of 

 heredity." Again Toyama,t as the result of a 

 prolonged examination of silk-worm crosses, 



* Science, N.S. vol. xix, no. 473, pp. 151-153. 

 t Biologisches Ccntralblatt, Juni I, 1906. 



