INTRODUCTION. 57 



They are insoluble in water but soluble in hot alcohol 

 and ether, forming compounds of carburetted hydrogen, 

 with some oxygen. 



Some of them by combining with an alkali, form soap 

 and with the oxyds of lead, plasters. 



This is effected by the acids they contain uniting with 

 the base and forming salts. 



Of the saponifiable fats, there are three substances re- 

 cognized as forming a base. 



1. Glycerin. 2. Oxyd of Cetyl. 3. Cerin. 



The first is the base of human fat, and is extensively 

 diffused among animals the second belongs to spermaceti 

 and the third to wax. 



Glycerin is obtained by boiling fat with oxyd of lead. It 

 is said to be sweet, yellow, without odor, soluble in water, 

 but not soluble in ether. 



The acids combining with this base are the stearic, mar- 

 garic and oleic forming stearin, margarin and olein, sub- 

 stances known familiarly as suet, lard and oil. 



The union of these two classes of elements in varied pro- 

 portions, constitutes the solids and fluids of the body. 



DEVELOPMENT OF ORGANIZATION. 



Organization, consisting as it does of a variety of parts, 

 we will briefly remark, advances by a series of steps not 

 simultaneously, but in a regular and definite succession, at 

 regular and definite periods after a regular and estab- 

 lished form and in obedience to established fundamental 

 laws. 



Special ^development will be noticed in the examination 

 of individual organs. 



Table of differences betiveen dead inorganic, and living or- 

 ganized bodies, as given by M. Magendie. 



These differences consist in the form, composition and 

 laws which govern them. 



