SALT AND ITS PHYSIOLOGICAL USES. 573 



suppression of mineral suits. The lack of common salt was, doubtless, 

 but a single factor in the production of these phenomena. The absence 

 of other salts, particularly of the phosphates, had also something to 

 do with it. Nevertheless, it is striking- to see what violent disturb- 

 ances may result from slight variations. In fact, the animal suc- 

 cumbed more quickly from the deprivation of mineral elements alone 

 than it would have done from total inanition, that is to say, from the 

 suppression of all aliments except water. 



The necessh^ for a modicum of common salt is shown by these 

 experiments. Chloride of sodium is then a plastic aliment. It is 

 placed by Munk and Ewald in the category of nutritive salts together 

 with the alkaline and earthy phosphates and the salts of iron. Accord- 

 ing to statistical data the daily consumption of salt in Europe is on the 

 average 17 grams per capita. Of these about 2 grams are necessary 

 to cover the loss by disassimilation. These two grams represent 

 nutritive salts. The remaining 15 grams would then represent on the 

 one hand 8 to 1<> grams carried away by excretions and necessary 

 for restoring the constitution of the circulating liquids, and a surplus; 

 but, considering the influence of salt upon the secretions, it would not 

 be prudent to say that this surplus is a sacrifice made to the pleasures 

 of appetite. 



We have just seen the ill effects of a deprivation of salt. We should 

 perhaps say a word about those which result from its excessive use. 

 It is known that if taken in amounts beyond the average it causes 

 thirst, and an increase in the renal excretion. It has been shown that 

 this increase remains about the same whether or not the subject drinks. 

 The water excreted is then taken from the tissues. 



If the absorption is pushed beyond moderate quantities, vomitings 

 and intestinal disturbances ensue. This kind of excess has rarely been 

 observed unless we regard as authentic the story of those midshipmen 

 who are said to have been compelled by Peter the Great to drink sea 

 water for the purpose of inuring them to a sailor's life and who died 

 as a consequence. 



VI. 



Besides taking an active part in certain of the vital phenomena, com- 

 mon salt fulfills better than any other substance the conditions of a 

 medium that is indifferent and yet suitable for the physiological neces- 

 sities of living matter. In animals as well as in plants, in the mobile 

 corpuscles of the blood as well as in the fixed elements of the tissues, 

 living protoplasm is always rich in potassic salts. The interior 

 medium which bathes it abounds, however, in sodic salts, particularly 

 the chloride of sodium, resembling in this respect sea water, which 

 might, if properly diluted, circulate in the veins and replace for a 

 time the plasma of the blood, as we have seen may be done with the 



