ORGANIC PRINCIPLES. 75 



are changed by the presence of certain organic substances in 

 the digestive fluids. Any process set up by the mere presence 

 of substances, which themselves undergo no chemical change, 

 or the transformation of one variety of organic matter into 

 another from the mere fact of contact, is called catalysis. 



The general properties we have mentioned are possessed 

 by all organic principles ; which, indeed, differ from each other 

 very little in their general characters, and even in ultimate 

 composition. Those which go to form the tissues are endowed 

 with identical vital properties. Robin and Yerdeil give seven- 

 teen distinct substances belonging to this class, of which four 

 are coloring matters. 1 But three of these principles have been 

 carefully studied with reference to their ultimate composition ; 

 but their composition, which is indefinite, and not necessary 

 to their vital properties, is of little physiological interest. 

 The number of equivalents of the various ultimate elements 

 is entirely arbitrary, as these principles enter into no definite 

 combinations. 



Table of Organic Principles. 



Name. Where Found. 



'Fibrin (C 298 H 228 6a N 40 S 2 ) Blood, Chyle, Lymph. 



( Blood, Chyle, Lymph, 

 Albumen ((WW).*.*). j Serosi ; ies ; M : ik : 



Albuminose Chyme, Blood. 



S 



Caseme(C 288 H 228 90 N 36 S 2 ) Milk. 



Mucosine Mucus. 



Pancreatine Pancreatic Juice. 



Pepsin Gastric Juice. 



fGlobuline Blood Globules. 



Musculine Muscles. 



Osteine Bone. 



Cartilagine Cartilage. 



Elasticine Elastic Tissue. 



Keratine Nails, Hair, Epidermis. 



.Crystalline Crystalline Lens. 



1 These authors do not consider that pepsin has been fully established as a 

 distinct proximate principle. Its distinctive properties seem to be sufficiently 

 well marked, and it has therefore been included in the list. 



