VII.] TRANSMISSION OF ACQUIRED CHARACTERS. 403 



have preferred to leave this discussion to a botanist, but I do 

 not know whether my views will meet with any support from 

 the followers of this subject, and I must therefore attempt the 

 discussion myself. And perhaps it is of some assistance in 

 clearing up the question, for one who is not accustomed to the 

 usual botanical views, and is more conversant with other classes 

 of biological knowledge, to consider the facts brought to light 

 by modern botany, from a general point of view. Of course I 

 shall not attempt to question the validity of the observations, 

 nor even the accuracy with which the facts have been inter- 

 preted. I shall only deal with the conclusions which may be 

 drawn from the facts, and I do not think that it is absolutely 

 necessary that such criticism should be made by a botanist. 

 Questions of general biological significance such as that of 

 heredity cannot be entirely solved within the single domain 

 of either zoological or botanical facts. Both botanists and 

 zoologists must give due weight to the facts of the province 

 which is not their own, and must see whether the views which 

 they have chiefly gained in the one province can be applied to 

 the other, or whether phenomena occur in the latter which are 

 in opposition to their previously formed views and which cause 

 them to be abandoned or modified. 



Detmer begins by bringing forward certain facts which prove, 

 as he believes, that rather important changes in the organism 

 can be directly produced by external influences. He is of 

 opinion that I under-estimate the weight of these influences, 

 and that I make light of the changes which may thus arise in a 

 single individual life. But obviously, it is of no importance for 

 the question of the transmission of acquired characters, whether 

 the changes directly produced by external influences upon 

 the soma of an individual are greater or smaller : the only 

 question is whether they can be transmitted. If they can be 

 transmitted, the smallest changes might be increased by sum- 

 mation in the course of generations, into characters of the 

 highest degree of importance. It is in this way that Lamarck 

 and Darwin have supposed that an organism is transformed by 

 external influences. It is therefore interesting to see what 

 Detmer considers to be a change which has been directly 

 effected. We can in this way gain a very distinct appreciation of 

 the difference in views which is caused by the different spheres of 



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