THE CHEMICAL BASIS OF THE BODY 751 



carbonate, in the urine principally as carbonate and some oxalate. 

 The amount of lime in some of the secretions may be judged from 

 the fact that in saliva it falls as a deposit on the fluid standing, 

 and in cow's milk it represents a loss to the animal of 42*5 grammes 

 CaO (i'5 ounces) every twenty-four hours. 



Phosphorus enters plants as phosphoric acid united with alkalis. 

 In soils it exists in only small quantities, hence the necessity of 

 phosphates as manure. In the plant phosphoric acid forms a part 

 of the complicated compounds known as lecithin and nuclein, in 

 which condition it enters the animal body, forming a part of both the 

 solid and fluid tissues. Once in the tissues, the body holds on firmly 

 to its phosphates, and only parts with them under pressure. 



A deficiency of organic phosphorus in the food appears to be 

 connected with a form of polyneuritis. Animals* fed on rice, barley, 

 or wheat flour, in which the outer layers of the grain have been 

 removed by milling, contract a disease apparently identical with 

 a form of beri-beri in man. This may be cured by the adminis- 

 tration of organic phosphorus in the form of beans, peas, testicular 

 extract, pancreas, or bran. The disease may even be prevented 

 if these be added to the incriminated diet. It is not known whether 

 the affection is due to the absence or deficiency of any special 

 member of the group, such as lecithin, nuclein, etc. Hutcheon, in 

 South Africa, showed the advantage of feeding on bone-meal in 

 cases of osteo-malacia in cattle. 



Phosphates are united with soda, potash, lime, and magnesia. 

 The foods richest in phosphoric acid are oilcake and bran, while 

 hay and straw are poorest in this substance. Phosphoric acid is 

 principally excreted by herbivora with the faeces, only small quanti- 

 ties passing away with the urine. 



Magnesium salts occur in the body principally as phosphates, 

 and in this form they enter largely into certain foods, such as oats. 

 The amount of magnesium passing away from horses through the 

 kidneys is small, but considerable quantities derived from the food 

 pass out with the faeces, as they cannot be utilised in the body. By 

 collecting in the bowels, this salt produces the ammonio-magnesium 

 phosphate calculi so common in horses. 



Sulphur exists largely in nature in combination as sulphates of 

 alkalis and alkaline earths. In this form it is taken up by plants, 

 and, becoming a part of their protein molecule, finds its way into the 

 body of the animal, where, by splitting up and oxidation, it yields 

 sulphuric acid. The bulk of the sulphur existing in proteins is split 

 off as cystine during hydrolysis, and furnishes the body with sulphur. 

 Eighty per cent, of the amount ingested reappears in the urine 

 combined with aromatic poisons, such as phenol, indol, etc., derived 

 from the putrefactive decomposition of protein in the intestinal 

 canal. The sulphuric acid formed from cystine is combined with 

 these poisonous products, which are thus safely escorted out of the 

 body. 



Carbonates are found in several of the secretions of the body, 

 notably in the urine of the horse, where they cause the most intense 

 evolution of gas on the addition of an acid The carbonates in the 

 system of the herbivora result from the carbonates of the food, 

 and the oxidation of vegetable acids, malic, citric, tartaric, etc. 



* Pigeons, rabbits, guinea-pigs, dogs, cats, goats. SeeEdie and Simpson, 

 British Medical Journal, June 17, 191 1, p. 142 1. 



