SUPERIORITY OF POTASSIUM SALTS. 35 



there can be no longer any doubt that sugars are produced by conden- 

 sation. As regards the formation of protein, the writer has on various 

 occasions pointed out that certain facts, especially the great rapidity 

 of protein formation in many instances and the absence of by-products 

 and between-products, inevitably lead to the assumption that in this 

 process also condensation plays an important part. 



But potassium salts are absolutely indispensable in animal life also, 

 although the synthetic work performed is not so far-reaching as in 

 plants. However, the formation of fats from sugar in the animal 

 body requires condensation as well as reduction, while the formation 

 of glycogen" from glucose and that of proteids from proteoses con- 

 sists in dehydration and polymerization. In such cases potassium 

 salts may play a role, and perhaps also in the processes of organiza- 

 tion, as, for example, in the leucocytes and gland cells, which latter 

 are in certain cases frequently renewed, or in the contractile substance 

 of the muscles when work or starvation have destroyed a part of it.* 



Nageli ascribed the differences in the physiological capacities of 

 potassium and sodium salts to their different affinities for water. So- 

 dium salts bind water of crystallization, but corresponding potassium 

 salts do not, and thus being free from such a dense sphere of water 

 the latter are better qualified for catalytic work. The dense layer of 

 water around the molecules of sodium salts would not only prevent the 

 salt itself from coming into immediate contact with other molecules, 

 but it also would impede an effectual transmission of vibrations. On 

 this basis also Nageli tries to explain the fact that the soil absorbs 

 potassium salts better than it does sodium salts, claiming that the lat- 

 ter are prevented by their water mantle from following the attracting 

 forces. However, objections can be easily raised to this view, the 

 most serious one being that by no means has every sodium salt the 

 water of crystallization. 



THE PHYSIOLOGICAL ROLE OF CALCIUM AND MAGNESIUM 



SALTS. 



DISTRIBUTION OF LIME AND MAGNESIA IN PLANTS. 



It has long been known that calcium and magnesium salts can not 

 physiologically replace each other, and the question as to the functions 

 of these salts has until recently been a matter of conjecture. The 

 striking regularity with which the leaves of plants show a relative 



" The liver, which is the principal organ in glycogen formation, contains, according 

 to Oidtmann, three times more potassium than sodium, while in the spleen the pro- 

 portion is, according to the same author, just the reverse. 



& Organization, as it takes place in a developing organ, is one of the least-known 

 vital processes. One thing, however, is sure, that is, that a connection of numerous 

 protein molecules in groups of a higher order takes place. This connecting process 

 was supposed by Pfliiger to consist in polymerization or etheriflcation. 



cSitzungsber. d. Bayr. Akad. Wiss., 1879, p. 348. 



