DEDUCTION. ANTICIPA TION. 149 



muscle would often be brought into play." He 

 himself observed children with reference to 

 this point, and had others, including physi- 

 cians, do so. He soon found that the "grief- 

 muscles " were very frequently brought into 

 very distinct action, and has given a number 

 of cases. The crying-muscles act in children, 

 and have acted for countless generations. The 

 pyramidal muscles are least under the control 

 of the will, and can be counteracted only by 

 the voluntary contraction of the central fasciae 

 of the frontal muscle ; and that is the expression 

 of grief. 



This instance of the solution of an inductive 

 problem is by its apparent smallness a striking 

 example of the difficulties of scientific investi- 

 gation, and of the necessity of appealing to all 

 the logical processes. After the explanation is 

 once made, it would seem an easy matter to ana- 

 lyze the complex effect called the expression 

 of grief, and discover its causes in the involun- 

 tary contraction of one set, and the voluntary 

 contraction of another set of muscles; but the 

 apparent simplicity is all due to the explana- 

 tion itself. It will be remarked, in the discus- 

 sion of the logical history of the principle of 

 natural selection, that the causes of any set of 

 facts are rarely discovered by a direct study 



