554 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



the amount of soda is equivalent to that of the potash in the 

 food of carnivora, in that of the herbivora the potash salts 

 are double in quantity those of soda. Comparison of results 

 of experiments showed that, while herbivora obtain no less 

 sodium and chlorine in their food than the carnivora, they 

 secure two to four times as much potash. By giving doses 

 of different potash salts, and determining the amounts of dif- 

 ferent salts excreted, he found, as the most evident effect, a 

 decided increase of sodium and chlorine on the day of ad- 

 ministration, and diminution below the normal amount on 

 the subsequent day ; and also that, besides chloride of sodi- 

 um, additional soda must have been excreted, since the sodi- 

 um, usually present in amounts chemically equivalent to the 

 chlorine, was in excess. Any explanation based on mechan- 

 ical displacement, increased diffusion and filtration of the 

 salt by the salts entering the blood, is not sustained by the 

 experiments; but it is more plausible to suppose that mutual 

 decomposition and recomposition of the potash salts intro- 

 duced, and of the soda salts in the blood, take place, and the 

 potash and soda salts thus formed, not being normal constit- 

 uents of the blood, are excreted. There are indications that 

 this change probably begins, and is carried on in part, in the 

 stomach and intestines. It also appeared that the phosphate, 

 after resorption, was partially combined with the blood cor- 

 puscles, and gradually given up by them, and that the blood 

 corpuscles, therefore, with their other functions, tend to ren- 

 der the harmful matter present in all nutriment harmless. 

 In support of this view, there is the fact that, in normal blood, 

 potash salts are found almost exclusively in the corpuscles, 

 and principally in combination with phosphoric acid, while 

 these salts are intensely poisonous in the plasma of the blood. 

 Although potash may, within limits, exceed soda in certain 

 food, without removing soda from the system (as in milk, the 

 food of young mammals), it must be remembered that the 

 greater part of the potassium in these cases is in the form of 

 chloride of potassium, which, according to incomplete experi- 

 ments, is less effective than other potassium compounds. 

 Since rye, potatoes, etc., the food of the laboring classes, con- 

 tain potash salts largely in excess of the soda salts, the au- 

 thor is inclined to regard common salt as a necessary nutri- 

 ment as well as a condiment. 28 C, July, 1873, 27. 



