36 INTRODUCTION. 



Parts per 1,000. 



In Saliva, Human (Lehmann) 1'530 



" Perspiration, Human (mean of three analyses, Piutti) 3*433 



" Urine (maximum) ) t 7'280 



" (medium).. [ Valentin, j 4.610 



" " (minimum)) ( 2'400 



" Fecal Matters (Berzelius) 3-010 



Function of Chloride of Sodium. The function of this 

 principle is undoubtedly important, but is not yet fully un- 

 derstood. It does not seem to enter into the substance of 

 the organized solids and semi-solids as an important and es- 

 sential element, but apparently exercises its chief function in 

 the fluids. It certainly determines, to a great extent, the 

 quantities of exudations, regulates absorption, and serves to 

 maintain the albuminoids, especially those contained in the 

 blood, in a state of fluidity. Albumen is coagulated by heat 

 with much greater difficulty in a solution of chloride of so- 

 dium than when mixed with pure water. A strong solution 

 of common salt is capable of dissolving casein, or of prevent- 

 ing the coagulation of fibrin. "We have already alluded to 

 the fact that it is the chloride of sodium particularly which 

 regulates the quantity of water entering into the composition 

 of the blood corpuscles, thereby preserving their form and 

 consistence ; and that it seems to perform an analogous func- 

 tion with reference to the other semi-solids of the body. 

 With regard to the general function of this substance, the 

 following proposition of Liebig is adopted by Robin and Yer- 

 deil, and a little reflection will show that it is sustained, as 

 far as we know, by the facts : 



" Common salt is intermediate in certain general pro- 

 cesses, and does not participate by its elements in the forma- 

 tion of organs" 



In the first place, the fluids of the body are generally in- 

 termediate in their functions, containing nutritious elements, 

 which are destined to be appropriated by the tissues and organs, 

 and worn-out elements, which are to be separated from the body. 

 In the blood and chyle chloride of sodium is found in greatest 



