DRINKING WATER. 135 



tains carbonate of lime in solution, than with soft water ; 

 because the oxide of lead which is formed by the action of the 

 oxygen in the water, is practically insoluble in water that 

 contains a fair quantity of carbonate of lime (Bloxam). 



Apparently, the only natural mineral impurities of water that 

 are desirable within narrow limits are carbonate of lime (chalk) 

 and common salt, the nutritive rdles of which have been already 

 discussed. The great objection to an excess of mineral 

 substances in drinking water is that they have a hurtful effect 

 on the stomach and intestines, either by their astringent or by 

 their laxative properties. " Hard water undoubtedly produces 

 a derangement of the intestinal canal, and sympathetically of 

 the skin ; the harsh staring coat of horses receiving hard water 

 rapidly disappears when a softer water is supplied. The amount 

 of hardness in water which will produce this derangement of the 

 intestinal canal has not been accurately determined, but from 

 eight to ten grains of lime per gallon has, in many cases, been 

 found injurious " (Fred. Smith}. I have never known a case 

 of illness in a horse being caused by the drinking of ordinary 

 hard water ; although every horse I have ever owned or trained 

 was watered almost exclusively on hard water. They were not 

 watered thus, because I was prejudiced one way or the other ; 

 but because hard water is the usual drinking water for man 

 and stabled beast, and what is good enough for the master is 

 generally considered to be good enough for the horse. I am 

 here, of course, speaking of ordinary spring or well water, and 

 not of mineral waters, which are " spring waters containing so 

 large a quantity of some ingredient as to have a decided 

 medicinal action " (Bloxam). 



The production of a tendency to the formation of calculi 

 (stones in the intestines, bladder, and elsewhere) has often been 

 put down to the drinking of hard water by horses, although 

 statistics are wanting to support the allegation. For instance, 

 Fred. Smith states that "cystic calculi among animals, 



