DEGENERA TION. 



concealed. So great is the value of hypothesis, so 

 essential to scientific discovery, that the most skilled 

 and highly-trained observer may spend his life in 

 examining and scrutinising natural objects and yet 

 fail, if he is not guided by hypothesis, to observe 

 particular facts which are of the uttermost import- 

 ance for the explanation of the causes of the things 

 which he is studying. Nature, it has been said, gives 

 no reply to a general inquiry — she must be interro- 

 gated by questions which already contain the answer 

 she is to give ; in other words, the observer can only 

 observe that which he is led by hypothesis to look 

 for : the experimenter can only obtain the result which 

 his experiment is designed to obtain. 



For a long time the knowledge of living things, of 

 plants and of animals could hardly be said to form 

 part of the general body of science, for the causes of 

 these things were quite unknown. They were kept 

 apart as a separate region of nature, and were 

 supposed to have been pitched, as it were, into the 

 midst of an orderly and cause-abiding world without 

 cause or order : they were strangers to the universal 

 harmony prevailing around them. Fact upon fact 

 was observed and recorded by students of plants and 



