CONCLUSIONS 221 



There seems to be a tendency among biologists of certain 

 schools to disregard every kind of evidence relating to the 

 transmission of hereditary characters, except that provided 

 by experiment. Such was not the method of Darwin, nor 

 does the truly scientific method exclude the use of facts, 

 whether recorded as results obtained under laboratory con- 

 ditions, or otherwise, so long as the facts are handled in a 

 properly scientific manner. The advantage of the experi- 

 mental results is that the laboratory conditions exclude 

 sources of error far more effectually than is possible in the 

 case of any other class of observations, and that to a great 

 extent, and very often, the laboratory conditions may be 

 reproduced and the experiment repeated. 



It is probable that no branch of knowledge would be 

 more hampered in its growth than the study of heredity 

 by a limitation to that kind of evidence only that can be 

 obtained in the laboratory. Nature is constantly carrying 

 out experiments under conditions the reproduction of which 

 is beyond our powers or knowledge. By observing her re- 

 sults and recording and interpreting as far as possible the 

 conditions under which they are produced, an advance in 

 knowledge is likely to be made, at least as great as by 

 experimental work. 



