302 ANDREW JACKSON HOWE. 



function. In seeking the cause of the variations ob- 

 servable in the organic world, we have to take into 

 account food, climatic influences, local and general 

 vicissitudes and necessities ; and in the recognition of 

 causes, we must admit that a certain degree of in- 

 telligence pervades the Universe. ~No one will attempt 

 to deny that lack of use results in atrophy and absolute 

 loss of structure ; and is not the evidence just as strong 

 that vigorous action tends to development ? The or- 

 ganic change may be slow in its manifestations, yet in 

 the infinity of time what is the necessity for haste ? 

 The ox while chewing the cud would suffer a dental 

 clash, if the creature possessed upper incisors ; the 

 horse by a tilt of the jaws can cut a mouthful of grass 

 with its upper and lower incisors, then use the grinders 

 without having the incisors touch each other in mas- 

 tication. The beaver can use its gnawing teeth all 

 day without having its grinders clash ; and then it 

 may masticate its food without the incisors meeting 

 each other. By an arrangement in the socket for the 

 condyles of the lower jaw, one set of teeth can be used 

 at a time, and the other be unemployed. Now, it is 

 not difficult to conceive how these articular changes 

 might be brought about in the course of time, if effort 

 be put forth to accomplish the object. 



In the contemplation of human anatomy, there is 

 much to be considered which is made philosophical by 

 comparing and contrasting features in the lower ani- 

 mals, and by keeping in mind that man is a mammal, 

 and embraces in his development many of the charac- 

 teristics of the inferior animals. The lower animals 

 are governed only by instincts, and are therefore re- 

 sponsible only to them. When a hawk swoops upon 

 a chicken or small bird, it does a cruel act, yet the 



