42 PHYSIOLOGICAL CHEMISTRY. 



QUANTITY OF SODIUM CHLORIDE IN 1000 PARTS IN THE 



Bones . . . . 7.02 Saliva .... 1.53 



Blood .... 3.36 Milk .... 0.30 



Bile .... 3.18 Lymph .... 5.00 



Gastric juice . . l.YO Sebaceous matter . . 5.00 



Perspiration . . 2.23 Urine . . 5.50 



One of the most important characters of this salt is its property of 

 regulating the phenomena of endosmosis and exosmosis, or the tran- 

 sudation of fluids through the organic membranes. This property 

 is shared by the other mineral ingredients of the blood, but is more 

 important in the case of sodium chloride, owing to its preponderance 

 in quantity over the rest. 



As sodium chloride is present in all parts of the body, it is also an 

 important ingredient of the food. It occurs in all animal food as a 

 natural ingredient of the corresponding tissues. In muscular flesh, 

 however, it is less abundant than potassium chloride, while, on the other 

 hand, it is more abundant in the blood. It exists also in various kinds 

 of vegetable food. 



According to Boussingault, it is found in the following proportions 

 in certain vegetable substances : 



PROPORTION OF SODIUM CHLORIDE IN 1000 PARTS IN 



Potatoes . . . 0.43 Oats . . . .0.11 



Beets . . . . 0.66 Peas .... 0.09 



Turnips .... 0.28 Beana .... 0.06 



Cabbage . . . 0.40 Meadow hay . . . 3.28 



The relative quantity of sodium chloride consumed in animal and 

 vegetable food has not been determined. In regard to the demand for 

 this salt, however, there is a striking difference between the carnivo- 

 rous and herbivorous animals. The carnivora receive a sufficient sup- 

 ply with their natural food, and usually show a repugnance to salt 

 as well as to salted meats. On the other hand, the horse and rumi- 

 nating animals have an instinctive desire for salt. They greedily devour 

 it, when offered to' them, in addition to that naturally contained in their 

 food, and it is shown by common experience that a liberal supply of 

 salt is important for their healthy nutrition. 



The same fact has been demonstrated in a more exact manner by the 

 experiments of Boussingault.* This observer made a series of com- 

 parative investigations upon the growth of two sets of bullocks of the 

 same age and vigor, and supplied equally with an abundance of ordi- 

 nary nutritious food, those of one set receiving in addition each 34 

 grammes of salt per day. At the end of six months the difference in 

 the aspect of the animals of the two sets began to be evident, and 

 became more marked as time went on. The experiment lasted for a 

 year, and at the end of that time both sets of animals had equally 

 increased in weight; but those fed with ordinary food presented a 



*Chimie Agricole. Paris, 1854, p. 251. 



