432 NUTRITION ANIMAL HEAT AND FORCE. 



has any accurate estimate been made of the quantity contained in the vari- 

 ous tissues, for all the chlorides are generally estimated together. It exists 

 in greatest proportion in the fluids, giving to some of them, as the tears and 

 perspiration, a distinctly saline taste. The following table gives the quanti- 

 ties found in some of the most important, of the fluids and solids : 



TABLE OF QUANTITIES OF CHLORIDES. 



Parts per 1,000. 

 In blood, human (Lehmann) 4-210 



In chyle (Lehmann) 5-310 



In lymph (Nasse) 4-120 



In milk, human (Lehmann) 0-870 



In saliva, human (Lehmann) 1-530 



In perspiration, human (mean of three analyses, Piutti) 3-433 



In urine (maximum) } ( 7*280 



In urine (mean) > Valentin. \ 4-610 



In urine (minimum) ) ( 2-400 



In faecal matters (Berzelius) 3-010 



Uses of Sodium Chloride. The uses of sodium chloride are undoubtedly 

 important, but are not yet fully understood. While it enters into the com- 

 position of the organized solids and semi-solids, as an important and essentis 

 constituent, it seems to exercise its chief office in the liquids. It is the sc 

 dium chloride particularly which regulates the quantity of water entering 

 into the composition of the blood-corpuscles, thereby preserving their forr 

 and consistence ; and it seems to perform an analogous office with regard 

 the other semi-solids of the body. The following brief statement expresses 

 the general uses of this substance in the economy : 



" Common salt is intermediate in certain general processes and does not 

 participate by its elements in the formation of organs " (Liebig). 



In the first place, the fluids of the body are generally intermediate in their 

 uses, containing nutritious matters, which are destined to be appropriated by 

 the tissues and organs, and excrementitious matters, which are to be separated 

 from the body. In the blood and chyle, sodium chloride is found in greatest 

 abundance. In the nutrition of tissues and organs, sodium chloride is not 

 deposited in any considerable quantity, but it seems to regulate the general 

 process, at least to a certain extent. In all civilized countries salt is used ex- 

 tensively as a condiment, 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 intermediate agent. There is nothing more 

 general among men and animals than this desire for common salt. In the 

 experiments made by Dailly on sheep and by Boussingault on bullocks, de- 

 priving these animals as nearly as possible of common salt for a number of 

 months, the general nutrition was affected without any marked change in 

 special tissues or organs. 



It is significant that the quantity of sodium chloride 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 quantity introduced with food, but the proportion in the blood is nearly 



