2 



ANIMAL MECHANISM. 



machines. In the course of this book, we shall frequently 

 borrow from pure mechanics the synthetical demonstrations 

 of the phenomena of animal life. The mechanician, in his 

 turn, may derive useful notions from the study of nature, 

 which will often show him how the most complicated problems 

 may be solved with admirable simplicity. 



Animal mechanics is a wide field for exploration. To 

 every function, so to speak, a special machinery is attached. 

 The circulation of the blood, the respiration, &c., may and 

 ought to be treated separately, so that we shall limit this work 

 to the study of one single, essentially mechanical, function, 

 locomotion in the various animals. 



It is easy to demonstrate the importance of such a subject as 

 locomotion, which, under its different forms, terrestrial, aquatic, 

 and aerial, has constantly excited interest. Whether man has 

 endeavoured to utilize to the utmost his own motive power, 

 and that of the animals ; whether he has sought to extend 

 his domain, to open a way for himself in the seas, or to rise 

 into the air, it is always from nature that he has drawn his 

 inspirations. We may hope that a deeper knowledge of the 

 different modes of animal locomotion will be a point of 

 departure for fresh investigations, whence further progress 

 will result. 



Every scientific research has a powerful attraction in itself; 

 the hope of reaching the truth suffices to sustain those who 

 pursue it, through all their efforts ; the contemplation of the 

 laws of nature has been a great and noble source of enjoy- 

 ment to those who have discovered them. But to humanity, 

 science is only the means, progress is the aim. If we can 

 show that a study may lead to some useful application, we 

 may induce many to pursue it, who would otherwise merely 

 follow it from afar, with the interest of curiosity only. 

 Without pretending to recapitulate here all that has been 

 gained by the study of nature, we shall endeavour to set 

 forth what may be gained by studying it still further, and 

 with more care. 



Terrestrial locomotion, that of man, and of the great mam- 

 mals, for instance, is very imperfectly understood as yet. If 

 we knew under what conditions the maximum of speed, force, 



