NATURAL THEOLOGY. 281 



about these animals is fitted for the pursuit of 

 iiviiig prey. Accordingly it has been found by 

 experiments, tried not many years ago, with per- 

 forated balls, that the gastric juice of ruminating 

 animals, such as the sheep and the ox, speedily 

 dissolves vegetables, but makes no impression 

 upon animal bodies. This accordancy is still more 

 particular. The gastric juice, even of granivorous 

 birds will not act upon the grain whilst whole and 

 entire. In performing the experiment of digest- 

 ing with the gastric juice in vessels, the grain must 

 be crushed and bruised before it be submitted to 

 the menstruum, that is to say, must undergo by 

 art, without the body, the preparatory action which 

 the gizzard exerts upon it within the body, or no 

 digestion will take place. So strict, in this case, 

 is the relation between the offices assimed to the 

 digestive organ, between the mechanical opera- 

 tion and the chemical process. 



II. The relation of the kidneys to the bladder, 

 and of the ureters to both, i. e., of the secreting 

 organ to the vessel receiving the secreted liquor, 

 ajid the pipe laid from one to the other for the 

 purpose of conveying it from one to the other, is 

 as manifest as it is amongst the different vessels 

 employed in a distillery, or in the communications 

 between them. The animal structure, in this case, 

 being simple, and the parts easily separated, it 

 forms an instance of correlation which may be 

 presented by dissection to every eye, or which, 



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