94 COSSING. 



ures, in terms of what we are used to think about in our work 

 with wheat or mice or snap-dragons. The isolation in which 

 these specialists elect to work is of their own making, but not 

 entirely. We, general Geneticians, who not so long ago felt un- 

 comfortable under the sense of being unable to digest this new 

 branch of literature, are beginning to console ourselves. A 

 great many of us are now hoping for the coming of an author, 

 patient enough, and broad-minded enough to try to translate 

 this imposing mass of work for us in terms familiar to us. We 

 trust that this will happen before the interest in Drosophila 

 dies of the very specialization and lack of relation to other 

 work, which so effectively killed the interest in Oenothera for a 

 time. Just as the self-sufficiency of the Oenothera-authors, who 

 used to work with names of types in a way wholly unfamiliar 

 to all the other students of Genetics, shut out and irritated us, 

 so are we beginning to resent, in the Drosophila-authors, not so 

 much the great apparent complacency with which they regard 

 each others diagrams of chromosomes, but the evident lack of 

 sense of proportion shown in the work. We mean here the lack 

 of interest in the work of the others, and in the relation of such 

 work to fundamental questions of common concern. Nobody 

 objects to specialization, but a great part of our beginning feel- 

 ing of resentment arises from the fact, that these specialists 

 evidently do not wish to leave speculations upon the broad is- 

 sues of Genetics to such men as Bateson, Morgan, Baur and 

 Johannsen, who are unhampered by specialization in the ma- 

 terial chosen. 



One of the terms we find recurring in the litterature on Dro- 

 sophila is the term "mutation." It is important to emphasize 

 that this use of the term is wholly in the Burbank sense, as sy- 

 nonymous to "novel character" and that it should not be 

 rashly concluded, that mutation in the sense of spontaneous 

 change in one or more genes is a rather common phenomenon 

 in this material. 



As we will try to show in the chapter on mutation, it is next 

 to impossible to prove the fact of a real mutation having oc- 



