THE INORGANIC FOODSTUFFS 131 



11. THE INORGANIC FOODSTUFFS 



A. GENERAL 



If an animal be fed proteid, fat and carbohydrates sufficient in quantity, 

 but deprived as far as possible of mineral constituents, very evident disorders 

 in the health of the animal soon make their appearance. Such food, poor in 

 salts, will not be eaten voluntarily, and even though the animal may receive 

 plenty of organic foodstuffs, and though he may absorb them for a long time 

 in perfectly normal fashion, he becomes continually weaker and gaunter. 

 Within two weeks symptoms of general weakness come on, the gait is sluggish 

 and staggering, the muscles tremble, and the animal becomes exceedingly 

 irritable in disposition. If the experiment be carried still further, convul- 

 sions ensue and finally death. 



If, late in the course of events, the animal's ordinary diet be restored, at 

 first he shows no desire to eat. The appetite however increases gradually, 

 and finally becomes ravenous. The symptoms of weakness, trembling of the 

 muscles, etc., pass away but slowly, and traces of them are to be observed 

 for a month or more after the salts are restored to the diet. 



It is perfectly certain therefore that the mineral constituents of the food 

 ore just as important as are the organic foodstuffs. In fact, it appears from 

 researches by Forster, that the body can endure absolute abstinence better 

 than it can endure deprivation of salts. 



In order to understand the reason for this great importance of the mineral 

 substances, it is necessary to know the effect of deprivation on the secretions 

 and excretions of the body. We saw above that digestion goes on normally 

 for a relatively long time; later, however (after three and one-half to four 

 and one-half weeks), digestive disorders are exhibited. The animal vomits 

 his food; or it may remain in the stomach for hours without being digested. 

 In any case the vomited contents always contain a fairly large quantity of 

 chlorine. 



Forster has shown that the excretion of P 2 O 5 never ceases entirely, it only 

 becomes less than with the usual food ; and, moreover, it decreases in proportion 

 to the quantity of ash-free food ingested. The same is true of NaCl: during 

 the first days of deprivation a relatively large quantity is excreted ; later it falls 

 off considerably so that finally in 200 cc. of urine only indeterminably small 

 traces could be demonstrated. During the last days, when the animal was draw- 

 ing heavily upon his own body for organic substances, larger quantities of NaCl 

 were given off in the urine. 



Forster considers himself justified by these experimental results in gen- 

 eralizing as follows : although the mineral constituents of the body are elim- 

 inated in smaller quantities when salts are no longer supplied, their excretion 

 never ceases entirely. The quantity eliminated is least when organic food- 

 stuffs are fed in abundance. 



This is because mineral constituents for the most part form loose com- 

 pounds with the combustible substances of the body, especially the proteids. 

 When organic foodstuffs are not supplied in sufficient quantity so that the 



