78 PHILOSOPHY OF ZOOLOGY. 



the urine of cows, from which it is extracted in France for 

 commercial purposes. 



F. Oxalic Add. This acid has hitherto been found 

 only in certain urinary calculi in union with lime. 



G. Acetic Acid. This acid has been detected in milk in 

 union with potash, by BEUZELIUS. 



H. Malic Acid. This acid has hitherto been found in 

 company with the formic acid, in the liquor obtained from 

 the red ant. 



In this short enumeration of the principles which enter 

 into the composition of animals, we perceive that carbon, 

 hydrogen, oxygen and azote, are found in the greatest 

 abundance. By combining in different proportions, they 

 exhibit a great variety of separate substances. The 

 earthy salts are likewise abundant ; and when they occur 

 in a separate state, they strengthen the albuminous frame- 

 work, and form the skeleton, giving stability to the body, 

 and acting as levers to the muscles. The alkaline salts 

 occur in the greatest abundance in the secreted fluids. 



These different principles, variously modified and mixed, 

 constitute the different parts of the animal frame. These 

 have been divided into two kinds, Fluids and Solids. 



The fluids consist of those juices which are obtained 

 from our food and drink, such as the chyle, and are termed 

 crude ; of the blood, prepared from the crude fluids, and 

 destined to communicate to every part of the body, the 

 nourishment which it requires, and of those fluids which are 

 separated from the blood in the course of circulation, such 

 as the bile, and termed Secreted Fluids. These are all 

 contained in appropriate vessels, and are subject to motion 

 and change. 



The Solids are derived from the fluids, and are usually 

 divided into the soft and hard. The soft solids consist 



