CHAPTEE X 



THE CARRYING OUT OF A BREEDING EXPERIMENT WITH 



A PLANT 



I HAVE two objects in view in dealing with this 

 matter : first, to render the reader familiar with 

 the means by which the facts which have already 

 been related have been determined, and in particular 

 to give directions for the repetition of the actual 

 crosses made by Mendel ; and, secondly, to lead up 

 to an exposition of Mendel's theory, through a 

 familiarity with the germ cells themselves, acquired 

 by actually handling them. 



I think it may be said that in the case of no other 

 branch of science can results of such interest be 

 obtained at so small a cost. The experiments by 

 means of which the high-water mark of modern 

 chemistry has been reached, such as — to take an 

 instance at random — the determination of the pro- 

 perties of radium, are so expensive that there are 

 few who can command the means to perform them, 

 and they are practically outside the reach of the great 

 mass of teachers of chemistry altogether. But in 

 the case of that branch of biology which, rightly or 

 wrongly, has attracted a share of interest which is 

 comparable with that attracted by radium in 



chemistry, the case is very different. The obser- 



X41 



