36 ILLINOIS STATE ACADEMY OF SCIENCE 



conditions, certain structures have changed steadily in 

 one direction, and these changes have resulted in the 

 origin and development of the various great groups. 

 What kind of variation furnishes the material for such 

 evolution, and what are the conditions that produce such 

 variations'? These questions have not been answered, 

 except in such a vitalistic way that the appeal is to faith 

 rather than to knowledge. 



In reviewing the status of the subject of evolution 

 today, it seems fair to conclude that competent opinion is 

 in a condition of flux, inclining now in this direction and 

 now in that as the results of experimental work are re- 

 ported. It is time for the open mind, for no one can fore- 

 tell what a day may bring forth. With Lamarck's view 

 once abandoned and now revived, Darwin's view once 

 accepted and now doubted, DeVries' view once hopeful 

 and now questionable, and all the other views fluctuat- 

 ing in apparent importance, no person is in a position 

 to pass judgment. My feeling is that we have been simply 

 playing with the surface, discovering minor factors, 

 drawing general inferences from special cases. This 

 was a necessary introduction to the subject. We begin 

 by wading in shallow water, and as we advance the water 

 gets deeper, until now we must realize that it is over 

 all our heads. 



