INORGANIC FOODS. 355 



the question that possibly the lack of salt may have had an indirect action. 

 In the catabolism of that part of albumin containing sulphur, the cystine, 

 there is formed, as we have seen, a considerable amount of sulphuric acid. 

 This under normal conditions will unite with the basic salts contained in 

 the nourishment and be eliminated as a salt of the acid. If now the 

 nourishment contains none of these basic salts, then the sulphuric acid 

 will constantly withdraw alkali from the cell components so that the 

 system will not only fail to have salts, but the whole structure of the cells 

 will be injured by taking away a part of the building material. Now if 

 such a hypothesis be correct, then the addition to the nourishment, which 

 is otherwise practically free from ash, of sufficient alkali to unite with this 

 sulphuric acid should enable the animal to live longer. Lunin 1 showed 

 by experiments that this was actually the case. He fed mice with casein, 

 fat, and cane-sugar. The amount of ash contained in this mixture was 

 only one-tenth of that in the mixture used by Forster. With this food 

 and distilled water five mice lived respectively, 11, 13, 14, 15, and 21 days. 

 Other mice were not given any food at all; two died in three, and two in 

 four days. 



Next Lunin fed six mice with the same mixture, to which some sodium 

 carbonate had been added. These animals lived 16, 23, 24, 27, and 30 

 days, or nearly twice as long as the mice did in the previous experiment. 

 Now the objection may be raised to this last experiment that here the 

 sodium carbonate may not act, as Bunge reasoned a priori, as an alkali, 

 but rather as a salt. In order to meet this objection, Lunin fed seven 

 mice with the same mixture, except that the sodium carbonate was replaced 

 by an equivalent amount of sodium chloride (common salt). These 

 animals died at the end of 6, 10, 11, 15, 17, and 20 days; i.e., they 

 did not live any longer than the mice in the first experiment. The experi- 

 ments were repeated with potassium carbonate and potassium chloride, 

 but with the same result. 



Now although the addition of sodium and potassium carbonate to such 

 a diet was sufficient to prolong the life of the animals, it was not able to 

 maintain their existence for any length of time. 2 Note, however, that, 

 these animals had received only one salt in the nourishment. It might 

 be thought that better results would be obtained with a mixture of salts. 

 Lunin, therefore, compared the lengths of life of mice fed upon cow's milk, 

 with that of mice fed with the above mixture of casein, fat, and cane- 

 sugar, plus the same salts that are contained in milk. Care was taken to 



1 Ueber die Bedeutung d. anorganischen Salze f. d. Ernahrung d. Tieres. Dissert. 

 Dorpat, 1880, and Z. physiol. Chem. 6, 31 (1881). 



2 Cf. C. A. Socin, Z. physiol. Chem. 15, 93 (1891). Abderhalden u. Rona, ibid. 42, 

 528 (1904). Henriques and Hansen, ibid. 43, 417 (1905). Falta and Noeggerath, Hof- 

 meister's Beitrage, 7, 313 (1905). 



