276 ANNUAL OP SCIENTIFIC DISCOVERY. 



in our diet without any disorder in the general harmony, but the inorganic 

 principles can only be replaced by substances very closely analogous to 

 them. Albumen, fibrin, and casein, and other more complex aliments, 

 though differing in origin and composition, may fulfil the same physiologi- 

 cal end, but it is different with inorganic principles. Lecanu has shown 

 that iron is indispensable for the proper constitution of blood-globules ; 

 chloride of sodium is of primary importance also as a constituent of the 

 liquor sanguinis ; and it is only as an exception that we find, in certain 

 gramnivora, this salt partially replaced by the phosphate of soda or of pot- 

 ash. Liebig has shown that the chloride of potassium of the muscles 

 cannot be replaced by chloride of sodium. Each inorganic constituent of 

 the organism has, therefore, its definite and limited sphere of action, to 

 which it is exclusively adapted. 



Among the indispensable inorganic salts, the phosphate of lime holds an 

 important rank. M. Mouries has devoted himself to the elucidation of 

 its peculiar action. He deduces from his experiments the following con- 

 clusions : 



1st. Phosphate of lime plays a more important part in nutrition than 

 has heretofore been believed. Independently of its necessity as a constituent 

 of bone, this salt maintains that irritability without which there is no 

 assimilation, and consequently no nutrition. Its insufficiency, therefore, 

 produces death with all the symptoms of inanition, while its insufficiency 

 in a less degree produces a series of lymphatic diseases. 



2d. The food consumed in cities is deficient in this respect. Nurses' 

 milk has, consequently, the same defect. The infant as well as the foetus 

 suffers from the deprivation of this element, so indispensable to its devel- 

 opment and life. Hence one of the causes of the increase in the number 

 of still-born children, and of the mortality of infancy. 



3d. The addition of this salt, in combination with animal matter, to 

 alimentary substances, obviates one cause of disease and death. 



The following are the principal facts on which M. Mouries relies to 

 establish these conclusions : 



The blood of animals contains a constant proportion of earthy phosphates, 

 which is independent of their ingesta. The pigeon ingests phosphate of 

 lime slightly in excess in the grain and calcareous gravels which it picks 

 up ; the horse swallows an excess in its fodder ; the dog procures a still 

 greater excess from the bones on which it is fed ; and yet the blood of the 

 pigeon contains ii^flOOO grammes 1.20 of phosphate of lime ; the horse 0.5 ; 

 the dog 0.4. This result is not accidental ; all birds whose blood has been 

 analyzed have 1.5 to 1.2 of phosphate of lime, while the proportion in the 

 blood of the carnivora and herbivora varies from 0.9 to 0.4. The propor- 

 tion thus regulated by Nature is modified by age and sex. The bull, cow 

 and calf have the same food, yet their blood contains respectively 0.5, 0.9, 

 0.8 of phosphate of lime. 



The requisite proportion of alkaline phosphates varies, therefore, in 

 different animals. A pigeon weighing one pound died at the end of ten 

 months, during which period he was fed daily on one oz. of wheat, with 



