72 GENERAL AND PHYSICO-CHEMICAL. 



ucts, are connected with the presence of water, and that besides this 

 the water by its evaporation is an important regulator of temperature, 

 it is evident that water must be a necessity of life. 



The mineral substances found habitually in the cells of higher plants 

 and of animals are potassium, sodium, calcium, magnesium, iron, phos- 

 phoric acid, sulphuric add, chlorine, and perhaps also iodine (JUSTUS). 1 

 Besides, in certain cells or organs we also find manganese, lithium, barium, 

 silicium, fluorine, bromine, and arsenic. 



* We are chiefly indebted to LIEBIG for showing that the mineral 

 bodies are as important for the normal constitution of the organs and 

 tissues, as well as for the normal performance of the processes of life, 

 as the organic constituents of the body. v The importance of the mineral 

 constituents is evident from the fact that we know no animal tissue 

 and no animal fluid which is free from, mineral bodies, and also from 

 the fact that certain tissues or tissue" elements contain chiefly certain 

 mineral bodies and not others. In regard to the alkali compounds this 

 division is, in general, as follows: The sodium compounds occur chiefly 

 in the fluids, while the potassium compounds occur especially in the 

 form-elements. C6rresponding to this, the cells contain chiefly potas- 

 sium as phosphate, while they are less rich in sodium and chlorine com- 

 pounds. * The fundamental experiments of FoRSTER 2 have shown us that 

 inorganic salts, as constituents of the food are necessary for the animal 



organism^ 



We have already called attention to the importance for every organ- 

 ism of the salts for the production of a rather constant osmotic pressure. 

 That the importance of the salts is not limited to the maintenance 

 of the osmotic pressure follows from the fact that different salt solutions 

 of the same osmotic pressure are not of the same value for the main- 

 tenance of the functional powers on extirpated organs. Since S. 

 RINGER 3 showed that various organic structures retained their best 

 functional activity in a solution which contained NaCl, CaCk. and 

 KC1 at the same time, various investigators, have given the most suit- 

 able composition of such solutions. For the transfusion fluid for the 

 mammalian heart LOCKE 4 suggests the following composition; NaCl 



1 Justus, Virchow's Arch., 170, 176 and 190. In regard to arsenic see the works 

 of Gautier, Compt. rend., 129, 130, 131, 139; Bertrand. ibid., 134; Segale, Zeitschr. 

 f. physiol. Chem., 42; Kunkel, ibid., 44. In regard to the barium see Schultze and 

 Thierfelder, Sitzungsber. d. Gesellsch. naturforsch. Freunde, 1905, No. 1, and in 

 regard to lithium see Hermann, Pflliger's Arch., 109; and in regard to manganese see 

 Bradley, Journ. of Biol. Chem., 3. 



2 Zeitschr. f. Biol., 9, 297 (1873); 12, 464 (1877). 



3 Journ. of Physiol., 6, 154, 361 (1885); 7,118(1886); 16, 1, 17, 23 (1895); 18, 

 425 (1896). 



4 Centralbl. f. Physiol., 14, 672 (1900). 



