134 GENERAL ANALYSIS. 



504. Illus. The Arteries or Veins of the Body 

 taken together are called the Arterial System, the Vein- 

 ous System, etc. 



505. FROM TISSUES, either of two modes of synthe- 

 sis of the Body may be chosen. 



506. TISSUES MAY BE FORMED into systems, and these 

 united into what will most properly be called the Human 

 System; or, 



507. TISSUES MAY BE WROUGHT into Organs, these 

 arranged as Apparatus, etc., and the Body produced. 



SECTION II. 



Fluids and their Properties. 



508. FLUIDS are not, strictly speaking, essential parts 

 of any organ ; yet as they are essential to the action of 

 each, and, in common with Tissues, are composed of 

 organic and chemical Elements, derived from air, water, 

 and food, they may be properly classed under the analy- 

 sis of organs. 



509. THE NECESSITY FOR FLUIDS is evidently of 

 three classes : 1 st, All substances that are to be moved 

 from one place to another, must be in a fluid condition. 

 2d, The surface of the Body must be protected by fluids. 

 3d, The Digestory processes, as we have seen, require 

 fluids for dissolving food. 



510. FLUIDS, THEREFORE, MUST BE of three classes, 

 General, Surface, and Digestory, of which the character 

 of the last has been shown. 



511. THE SURFACES of the Body are of three kinds : 

 1st, that of the external skin ; 2d, those of the lining 

 of the air and food canals ; and, 3d, those where the or- 

 gans only are in contact with each other. 



512. THE SURFACE OF THE EXTERNAL SKIN RE- 



604. Illustrate. 506. How ? 50T How? 508. What enid of ? 609. What 

 said ? 610. How class ? 51 1 . How class ? 512. What does ? 



