ORGANIC IMMEDIATE PRINCIPLES. 



Chemistry alone, then, does not give a just idea of the organic sub- 

 stances; their examination is a part of anatomy. "It is not carbon, 

 hydrogen, oxygen, and nitrogen which directly form the organized 

 substance, but bodies composed of these, which act directly, and 

 which naturally arrange themselves in three distinct classes." (Ro- 

 bin and Verdeil.) 



The organic substances leave the body after e&s-assimilation, in 

 the form of lactic and uric acid, urea, carbonic acid, water, &c. 

 Creatine may pass into creatinine, and subsequently into urea, and 

 then appear in the urine, it being principally derived from the dis- 

 assimilation of musculine. Albumen and gelatine may also pass 

 into leucine, the gelatine being derived from the dis-assimilation of 

 the osteine in bone and white fibrous tissue, as before stated. 



Classification of the Organic Immediate Principles. 



The organic substances are eighteen in number, the first two 

 divisions of them constituting the "albuminous compounds." Al- 

 bumen, caseine, and fibrine have recently been termed the "proteine 

 compounds," since a compound called proteine, and represented by 

 the formula C 36 H 25 N 4 10 +2HO (Mulder), is obtainable from them 

 all, and which has been assumed to be their compound radical. 



Proteine does not, however, exist in nature. It is obtained only 

 by the destructive decomposition of these substances, and, therefore, 

 however convenient to the chemist, it has no interest in histology. 

 Two oxides of proteine are said to exist in the blood the binoxide 

 and the tritoxide; the latter during inflammations more especially. 

 What their relations to the tissues are, is, however, unknown. 



Nor do we admit the "gelatinous compounds" hitherto described. 

 Gelatine (or glutin) and chondrine do not exist naturally in the 

 human body, but are formed from osteine and cartilageine respect- 

 ively, by chemical agency, as will be explained in the description 

 of these two organic substances. 



FIRST DIVISION. 



Those Naturally in a Fluid State. 



Of these seven substances, pancreatine, mucosine, and ptyaline 

 have no special importance in histology, but will be again alluded 

 to in the part describing the fluids in the human body. 



Pancreatine is found only in the pancreatic fluid. 



Ptyaline is found only in saliva. 



