INTRODUCTION. 



Combined with these organic principles we always have 

 a certain proportion of inorganic matters which may, it is 

 true, be separated from them easily, and apparently without 

 decomposition, but which are, notwithstanding, necessary to 

 the peculiar properties by which we recognize organic sub- 

 stances. Their physiological union is so intimate that they 

 may justly be considered as organic, though originating in 

 the inorganic kingdom. 



Chemistry recognizes fifty-nine elementary substances, of 

 which some fifteen or eighteen enter into the constitution of 

 the human body ; but as physiologists, we must make a 

 division of the body into component principles, without 

 reference to the elementary substances themselves, but with 

 a view to the form and condition of their existence in the 

 organism. As we have seen that the distinguishing properties 

 of organic principles are destroyed when they are reduced to 

 their ultimate elements, it is evident that many or most of 

 the principles into which the body is divided physiologically 

 are compound substances. 



From this point of view, the organism may be said to be 

 composed of Immediate or Proximate Principles. 



A Proximate Principle may be defined to be a substance 

 extracted from the body, which cannot ~be further subdivided 

 without chemical decomposition and loss of its characteristic 

 properties. 



According to Hobin and Yerdeil, there exist from eighty- 

 five to ninety distinct proximate principles in the human 

 body. 1 



The distinction between proximate principles and chem- 

 ical elements is apparent from the definition above given. 

 To illustrate this difference, however, we may take the fol- 

 lowing example. Chloride of sodium is an important proxi- 

 mate principle, and is composed of the chemical elements 

 chlorine and sodium. As chloride of sodium, it has certain 



1 ROBIN and VERDEIL, Chimie Anatomique et Physiologique, Paris, 1853, 

 tome i., p. 128. 



