PROXIMATE PRINCIPLES. 19 



are very delicate, and are not stratified. They are of various forms, 

 usually irregularly polygonal, and are joined at the edges so as to 

 form a sort of mosaic. 



What are connective tissues? 



They are the structures which form the frame and supports of 

 the body and of the organs of the body. The ligaments, tendons, 

 fasciae, cartilage, and bones are examples of them. The fibrous 

 connective-tissue cells are found in all organs in greater or less 

 amount. In the organs whose use is the support of the body or 

 one of its members these cells predominate. In other organs the 

 fibrous cells serve to hold in place the functional cells and to 

 maintain the shape of the organs. 



What are the proximate principles of the body ? 



They are the substances entering into the composition of the 

 body, and are inorganic and organic. 



What are the inorganic elements? 



Chemically, C, H. 0, N make up a very large portion of the 

 body-weight, water alone (H. 2 O) forming about three-fourths of 

 the total. Besides these, sodium, potassium, lime, and magnesium, 

 in chemical combinations with sulphur, phosphorus, chlorine, and 

 Carbon (sulphates, phosphates, chlorides, and carbonates), are 

 found in considerable amounts, and less abundantly iron, silica", 

 and fluorine. Occasionally minute quantities of some of the other 

 metallic elements arsenic, lead, copper, and manganese are found. 



How are the organic proximate principles classified ? 



(1) Nitrogenous, and (2) non-nitrogenous. 



(1) The former take the principal part in the formation of solid 

 constituents of the body, and occur in all the body tissues and 

 fluids. They make up the protoplasm of cells and essential in- 

 gredients of the fluids, both circulatory and excretory. Chemi- 

 cally, they are compounds of C, H. 0, N, sometimes with sulphur 

 or phosphorus. 



(2) The latter (non-nitrogenous) class of bodies are made up of 

 the fats and carbohydrates. 



What is the reaction of the fluids of the body ? 



Alkaline, with only four notable exceptions. These are gas- 

 tric juice, perspiration, vaginal mucus, and acid urine. 



