Laws of Fluctuations 741 



Eecapitulating the results of this too con- 

 densed discussion, we may state that fluctua- 

 tions are linear, being limited to an increase and 

 to a decrease of the characters. These changes 

 are mainly due to differences in nourishment, 

 either of the whole organism or of its parts. 

 In the first case, the deviations from the mean 

 are called individual ; they are of great impor- 

 tance for the hereditary characters of the 

 offspring. In the second case the deviations 

 are far more universal and far more striking, 

 but of lesser importance. They are called par- 

 tial fluctuations. 



All these fluctuations comply, in the main, 

 with the law of probability, and behave as if 

 their causes were influenced only by chance. 



