20 Journal of the Mitchell Society [July 



the purity of the strain, nevertheless in the present state of 

 our knowledge it would seem wiser to account for them as a 

 result of hybridization far back in the line, than as the pro- 

 duction of an entirely new character by the operation of some 

 as yet wholly unknown force. 



While this would seem to be true it is possible that it does 

 not apply to all cases. De Vries divides his mutants into 

 two classes, one characterized by the appearance of a char- 

 acter wholly new, and the other by the loss of some character 

 previously possessed. This latter, it would seem, might and 

 probably does occur with the intervention of hybridization. 

 It is a matter of common knowledge that accidents happen 

 during the embryonic history of the individual which pre- 

 vent the development of organs and tissues and, to me at any 

 rate, it is no more difficult to think that certain conditions 

 might, even in the germ cells, destroy, some one of these units 

 of living matter which would otherwise in the mature animal 

 express itself as a character. For example, albinos are simply 

 animals in which for some reason or other the color factor has 

 failed to express itself. Granting this, however, the tendency 

 of present investigation is to rob mutation of any really great 

 significance in the hypothesis of descent and perhaps throw 

 us back either to Darwin or Lamarck. 



ACQUIRED CHARACTERS 



Whether acquired characters are inherited or not consti- 

 tutes for biologists a seemingly eternal question. Are dis- 

 eases, mutilations, habits, the effects of use and disuse handed 

 on to offspring — these are some of the forms in which the 

 query has been put. But from whatever angle the problem be 

 approached the real aim has been to find whether or not the 

 environment can in any way reach and impress itself upon 

 the germinal substance so that its effects may be transmitted. 

 That such is the case was generally believed a hundred years 

 ago and the idea was made the foundation of the theory of 

 evolution propounded at that time l)v the celebrated French 

 biologist Lamarck. 



