The Experimental Method 1 1 



hard to draw, and since I shall not hesitate at times to enter 

 upon the physiological side of many problems, I have chosen 

 the somewhat broader title of Experimental Zoology to include 

 the subjects to be treated. 



The principal topics to be discussed fall under the following 

 six headings : 



I. Experimental Study of Evolution. 

 II. Experimental Study of Growth. 



III. Experimental Studies in Grafting. 



IV. Experimental Studies of the Influence of the Environ- 



ment on the Life-cycle. 



V. Experimental Study of the Determination of Sex. 

 VI. Experimental Study of the Secondary Sexual Characters. 



