146 THE METHOD OF DARWIN. 



with their own form pollen, which his experi- 

 ments of 1 86 1 had brought out, by carrying 

 through a long series of experiments which, as 

 he said, were so curious that he gave them in 

 detail. His conclusion from the experiments is 

 that although the pollen of the two forms is iden- 

 tical under the microscope, "taking fertility as 

 a criterion of distinctness, it is no exaggeration 

 to say that the pollen has been brought to a de- 

 gree of differentiation, with respect to its action 

 on the stigma of the same form, corresponding 

 with that existing between the pollen and stigma 

 of species belonging to distinct genera." l 



An excellent illustration of the relation 

 between induction and deduction in the scien- 

 tific method is furnished by Darwin's study of 

 the expression of grief. During several years, 

 he said, no expression seemed to him so utterly 

 perplexing as this one. Why should the inner 

 ends of the eyebrows be raised when a person 

 feels the emotion of grief? Or, in other words, 

 what is the cause of the obliquity of the eye- 

 brows under suffering? "Why should grief or 

 anxiety cause the central fasciae alone of the 

 frontal muscle, together with those round the 

 eyes, to contract?" 2 Here was a little induc- 



1 Different Forms of Flowers, etc., pp. 87-90. 



2 Expression of the Emotions, etc., pp. 188-192. 



