SUBSTANCES WHICH PASS THROUGH THE ORGANISM. 431 



TABLE OF QUANTITIES OF WATER. 



Parts per 1,000. 



f In the enamel of the teeth 2 



In epithelial desquamation 37 



In teeth 100 



In bones , 130 



In tendons (Burdach) 500 



In articular cartilages 550 



In skin (Weinholt) 575 



In liver (Frommherz and Gugert) 618 



In muscles of man (Bibra) 725 



In ligaments (Chevreul) 768 



In the blood of man (Becquerel and Rodier) 780 



In milk of the human female (Simon) 887 



In chyle of man (Rees) 904 



In bile 905 



In urine 933 



In human lymph (Tiedemann and Gmelin) 960 



In human saliva (Mitscherlich) 983 



In gastric juice 984 



In perspiration 986 



In tears 990 



Uses of Water. After what has been stated with regard to the condition 

 in which water exists in the body, there remains but little to. say concerning 

 its uses. As a constituent of organized tissues, it gives to cartilage its elas- 

 ticity, and to tendons their pliability and toughness ; it is necessary to the 

 power of resistance of the bones, and it is essential to the proper consistence 

 of all parts of the body. It also has other important uses, as a solvent. 

 Soluble articles of food are introduced in solution in water. The excremen- 

 titious products, which generally are soluble in water, are dissolved by it in 

 the blood, are carried to the organs of excretion, and are discharged in a 

 watery solution from the body. 



Origin and Discharge of Water. It is evident that a great proportion of 

 the water in the organism is introduced from without, in the fluids and in 

 the watery constituents of all kinds of food ; but water is also formed in the 

 body by a direct union of oxygen and hydrogen. The evidences of forma- 

 tion of water in the body have already been given, in connection with the 

 question of water considered as a product of excretion, and will be again dis- 

 cussed in treating of the relations of water to the processes of calorification. 

 In the discharge of water by the kidneys and skin, it has long been observed 

 that in point of activity these two emunctories bear a certain relation to 

 each other. When the skin is inactive, as in cold weather, the kidneys dis- 

 charge a large quantity of water ; and when the skin is active, the quantity 

 of water discharged by the kidneys is proportionally diminished. 



Sodium Chloride. Sodium chloride is next in importance, as an inor- 

 ganic constituent of the organism, to water. It is found in the body at all 

 periods of life, existing even in the ovum. It exists in all the fluids and sol- 

 ids of the body, with the single exception of the enamel of the teeth. The 

 exact quantity in the entire body has never been ascertained ; nor, indeed, 



