136 Analysis of Scientific Books. 



the same principle, to enable it to retain itself upon the slippery 

 rocks which it climbs, and thus to prevent its falling backwards into 

 the sea. 



On the subject of digestion the author has taken infinite pains, 

 both as regards the anatomy of the organs and the phenomena of the 

 process; he deserves to be attentively consulted by all those who 

 venture upon that difficult investigation, and when we find from his 

 experiments that the horny part of the bird's gizzard coagulates milk 

 in the same way as the gastric secretion, and thus appears to a su- 

 perficial observer to possess the power of digesting, we cannot but 

 smile at disputes which have arisen among physiologists of repute 

 respecting that very important but recondite process, some main- 

 taining, whilst others deny, that the division of the gastric nerves 

 impedes or prevents that process altogether; while others tell us that 

 by bringing their divided ends into contact, their functions are pre- 

 served and the operation continued. But how is all this ascertained ? 

 It is said by fair and convincing experiments. But how was the 

 digestion demonstrated ? Why, two rabbits were crammed with parsley 

 previous to the experiment, and afterwards, upon examining the 

 contents of the stomach, the parsley was digested in the one case, and 

 unmixed, unaltered in the other. — We purposely abstain from any 

 remarks upon the electrical part of this inquiry, but arc inclined to 

 ask, in which cavity of the rabbit's stomach the parsley was found? 

 the stomach of that animal having two cavities, the one to prepare 

 and macerate, the other to dissolve and digest. — We believe it was in 

 the former — and in what state ? Either upon the surface, above the 

 other contents, unchanged, or more or less mixed with the other 

 contents, and consequently, more or less acted upon by the juices 

 with which they were previously imbued. Allowing, then, the greatest 

 latitude for deduction, we ask what such experiment proves ? It 

 proves, supposing all preliminaries correct, that when the nerves are 

 divided and their ends turned asunder and kept separated, that the 

 muscular coats of both cavities of the stomach cease to act ; but that 

 when the divided ends of the nerves are left in contact, or again 

 brought together, the motion of both portions of the stomach is re- 

 newed, and the contents blended together, this being the end for 

 which each muscular action of the stomach is ordained. But all 

 this is entirely independent of digestion properly so called — digestion 

 is performed in the other cavity of the stomach. 



The formation of the teeth is a very curious subject of inquiry, es- 

 pecially as relates to their variety of formation according to the 

 different purposes for which they are intended in the different tribes 

 of animals. The grinders of the Elephant furnish us with a very 

 remarkable assemblage of three substances of different degrees of 

 induration, which our author shews (Vol. III.) to correspond in 

 texture to bone, ivory and enamel. 



Concerning the stomach and its functions, many interesting matters 



