INORGANIC FOODS. 365 



We perhaps do not yet know all the different ways in which potash can be 

 eliminated. We shall see that for the heavy metals the intestines are an 

 important vehicle for their elimination. It is even possible that the liver 

 regulates the amount of potassium salts, holding a part back so that the 

 blood does not at any one time come in contact with large amounts of 

 them. At all events, the influence of potassium salts contained in the 

 food upon the elimination of sodium salts by the urine must be tested with 

 some food, such as potatoes, which is rich in potassium salts. The exper- 

 iment should extend over a considerable period in order to determine 

 whether any loss of sodium chloride is permanent or only temporary. 



The organism must in every case have ways and means for keeping the 

 soda and potash content of the blood constant in spite of variations in the 

 food supply. It is worthy of mention that the serum of all species of 

 animals * which have been investigated up to the present time always 

 contains the same amounts of these two elements; the serum of the car- 

 nivora, as well as that of the herbivora, contains about . 43 per cent of 

 soda, and 0.026 per cent of potash. Perhaps the fact that the red cor- 

 puscles of the ruminants, in contrast to those of the horse, cow, rabbit, etc. r 

 contain considerable amounts of soda, may shed some light upon the fact 

 that the former crave salt, while the latter do not. To be sure, the red 

 corpuscles of the carnivora also contain larger amounts of soda. It is 

 very interesting that in the milk of carnivora the two alkalies are present 

 in approximately equivalent amounts, whereas in the milk of the herbivora. 

 and in human milk the potash predominates. The organism of the her- 

 bivora and of the carnivora, corresponding to their later nourishment,, 

 thus early becomes accustomed to a definite relation between the amounts 

 of potassium and sodium. The beasts of prey, which live upon the entire 

 animal, obtain sodium and potassium in almost equivalent amounts. On 

 the other hand, the herbivora and the human race receive in many foods 

 the two bases in the same relative amounts as in milk; some kinds of hay 

 contain three equivalents of potash to one in soda, while in milk there are 

 from one to six equivalents of potash to one of soda. We may, indeed, 

 assume that the organism is adjusted to the general preponderance of 

 potash over soda, and that disturbances take place only when the cus- 

 tomary relation is changed greatly at the expense of the sodium, as would, 

 for example, be the case if the food consisted entirely of potatoes. Rye, 

 peas, and beans likewise contain very considerable amounts of potassium, 

 as the following table prepared by Bunge shows: 



1 Abderhalden: Z. physiol. Chem. 25, 65 (1898). 



