INORGANIC PRINCIPLES. 493 



ly it 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 sodium than when mixed 

 with pure water. A strong solution of common salt is capable of dissolving caseine or 

 of preventing the formation 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 function with regard to the other semi- 

 solids of the body. As to the general function of this substance, the following proposi- 

 tion of Liebig is adopted by Robin and Verdeil, 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 processes, and does not participate 

 by its elements in the formation of organs." 



In the first place, the fluids of the body are generally intermediate 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 abundance. As the nutrition of organs 

 occurs, which consists in the fixation of new proximate principles, chloride of sodium is 

 not deposited in any considerably quantity, but it seems to regulate the general process, at 

 least to a certain extent. In all civilized countries, salt is used extensively as a condi- 

 ment, and it undoubtedly facilitates digestion by rendering the food more savory and 

 increasing the flow of the digestive fluids ; here, likewise, acting simply as an interme- 

 diate agent. There is nothing more general among men and animals than this desire for 

 common salt. The carnivora crave it and obtain it in the blood of animals ; the her- 

 bivora frequent " salt licks " and places where it is found, and relish it when mixed with 

 their food ; and by man its use is almost universal. In the domestic herbivora, the 

 effect of a deprivation of this article is very marked and has been made the subject of 

 some very interesting experiments, by Boussingault. This observer experimented upon 

 two lots of bullocks, of three each, all of them, at the time the observations were com- 

 menced, being perfectly healthy and in fine condition. One of these lots he deprived 

 entirely of salt, except what was contained in their fodder, while the other was sup- 

 plied with the usual quantity. No marked difference in the two lots was noticed until 

 between five and six months, when the difference in general appearance was very distinct. 

 The animals receiving salt retained their fine appearance, while the others, though not 

 diminished in flesh, were not so sleek and fine. At the end of a year the difference was 

 very marked. The hides of those which had been deprived of salt were rough and ragged, 

 and their appearance, listless and inanimate, contrasting strongly with the sleek appearance 

 and vivacious disposition of the others. The experiments of Boussingault are the most 

 conclusive that have ever been instituted with regard to the influence of chloride of sodium 

 upon nutrition. They indicate a certain deficiency in the nutrition of animals deprived 

 of it, but not any considerable loss of weight. Before these observations were made, 

 Dailly made analogous experiments upon twenty sheep, which were continued for three 

 months. At the end of that time, the lot which received salt presented a considerable 

 excess of weight (about 22f Ibs.) over the others. 



It is a significant fact that the quantity of chloride of sodium existing in the 

 blood is not subject to variation, but that an excess introduced with the food is thrown 

 off by the kidneys. The quantity in the urine, then, bears a relation to the amounf 

 introduced as food, but the proportion in the blood is constant. This is anothei 

 fact in favor of the view that the presence of a definite quantity of common salt in 

 the circulating fluid is essential to the proper performance of the general function of 

 nutrition. 



Origin and Discharge of Chloride of Sodium. This substance is always introduced 



