CLASSIFICATION. 39 



are their remote or elementary principles" 1 It will appear that the 

 three gases just mentioned are, however, also immediate principles 

 in certain circumstances. 



Thus the study of the immediate principles of organized bodies 

 is intermediate between mere organic chemistry on the one hand, 

 and histology on the other, and must precede the latter. 



CLASSIFICATION OF THE IMMEDIATE PRINCIPLES IN THE 

 HUMAN BODY. 



The number 2 of immediate principles in the human body is not 

 precisely determined; but the following classification, embracing 

 84, may be for the present adopted. 



These 84 substances, being all compound except oxygen, hydro- 

 gen, and nitrogen, are divided into two groups: 



I. The first group includes those principles which are crystal- 

 lizdble or volatile, without decomposition. These are di- 

 vided into two classes : 



1st. Principles of mineral origin, 24 in number. 



2d. Principles formed within the body by dis-assimila- 



tion, 3 and therefore of organic origin, 42 in number. 

 II. The second group includes those which are not crystalliza- 

 ble, or not volatile, except in consequence of decomposition ; 

 only 18 in number. This group is not divided, and con- 

 stitutes the third class, organic substances. 

 The three classes are divided as follows : 



A. Of the first class principles of mineral origin there are 



two divisions. 



1st. Gaseous or liquid, and not saline bodies, 5 in number. 

 2d. Saline bodies (salts), 19 in number. 



B. The second class principles of organic origin has four 



divisions : 



1st. Acid or saline principles, 23 in number. 



2d. Neutral nitrogenized compounds, generally called 



nitrogenized alkaloids, 4 in number. 

 3d. Neutral ncw-nitrogenized compounds or sugars, 2 in 



number. 



1 Recherches Chimiques sur les corps gras d'origine animale. Paris, 1823, p. 4-5. 



2 Robin and Verdeil reckon 92 immediate principles in man and the mammiferce. 



3 This word implies the same as the terms " waste" or " metamorphosis" of the 

 tissues. 



