414 INORGANIC ELEMENTS OF FOOD. 



quantity of lime is incompetent to maintain the bones in their stan- 

 dard condition. I have thought it of moment to insist upon these 

 facts, because I see that they may sometimes come into play m practi- 

 cal rural economy. No breeder or feeder ought to be ignorant of 

 the influence of mineral substances on nutrition. It is not only indis- 

 pensable that the allowance of an animal in full growth be sufficient 

 to support, and even to add to the soft textures ; it must further con- 

 tain the elements requisite for the nutrition of the osseous system : 

 and it is not impossible but that, in managmg the feeding of young 

 cattle or young horses in such a way as to reduce to a minimum, or 

 to give in excess, certain of the inorganic elements of the food, we 

 may succeed in impressing one character or another upon a race. 

 It is even possible that the empirical rules which are acted upon 

 \vith a view to increase or diminish the quantity of bone, the weight 

 of flesh or of fat, &c., are all connected with various proportions 

 of phosphoric acid, of lime, magnesia, &c., in the food. It will 

 probably be discovered, some day, that BakewelTs art is to be ex- 

 plained through the composition of the ashes of the food. 



Wheat is not the only alimentary matter that contains an insuf- 

 ficient quantity of lime ; maize or Indian ctirn contains still less : 

 and if that which is grown in the tropics contains as little as that 

 which is produced in Europe, it would be difficult to explain how 

 the grain should answer so well as it unquestionably does for food* 

 It is true that it is seldom or never consumed aU)ne and without 

 addition ; and in South America, where the animals have it largely, 

 I have observed that they frequently eat earth. The habit which 

 certain tribes of the natives have oi' eating earth, too, which has 

 been particularly remarked upon l»y travellers and missionaries as an 

 instance of depravation of taste, presents itself to me in quite another 

 light, since I becaine acquainted with the coinposilion of the ashes 

 of the ordinary article of diet in the countries where it occurs. f 



The calcaretuis and other salts necessary to nutrition, how- 

 ever, are not derived from the food exclusively ; the water that is 

 generally consumed contains a quantity which is by no means to be 

 neglected. A horse or a cow, for instance, which drinks from 15 

 to 45 quarts of water per diem, will even, if the water be as pure as 

 that of the Artesian well of Grenelle, take in from 35 to 108 grains 

 of saline matter in which carbonate of lime predominates ; water that 

 is less free from saline impregnation would «>f course introduce a 

 much larger proportion ; some waters in the quantities above speci- 

 fied will contain from 138 to upwards of 400 grains of saline matter, 

 one half of which may be carbonate of lime. And I am here speak- 

 ing of clear or filtered water ; that whicli is muddy or turbid con- 

 tains a still larger quantity of eartliy matter in suspension than in 

 stilulion. In an experiment made fi)r the purp«»se of getting at the 

 amount of earthy matter taken by a milcli-cow from the watcring- 



* .\n nsh of in-\izo. annlyzed in my 1 \ln>rTitt>ry h\ M. lA!tcHicr, contained but IJ pel 

 •eiit. of lime to 50.1 of phosplioric iiciil ami 17.0 ul in :tpnt">l:i. 



t I seviTil times saw childrea chaiili;u:U m Indian villages who bad t>ccn caugk 

 •atiiig earth. 



