Special Functions and Relations 



173 



involved in carbohydrate, fat, and protein making, the 

 relation of potassium to general metabolism is deduced. 



The potassium and protein relation. The relation 

 between protein and potash in storage organs has also been 

 shown to be suggestive, at least to this extent : Seeds or 

 other organs rich in protein are generally relatively rich 

 in potash, although there is no definite ratio. Loew cites 

 certain analyses of Wolff which may be summarized in the 

 following table : - 



The osmotic relation and winter injury. - - It has been 

 generally held that another important role of potassium 

 may be found in its action as an osmotic agent. Some 

 plants contain relatively large quantities of potash in their 

 juices, as K 2 SO 4 , KNO 3 , KH 2 PO 4 , and certain organic 

 salts. Other plants, however, have high osmotic coeffi- 

 cients on account of organic substances, and there seems 

 to be no sufficient reason why as an osmotic agent the 

 potassium is to be regarded as having a constant role. 

 In fact, the view seems to be justified that in so far as po- 

 tassium is necessary osmotically it may be replaced by 

 sodium. Certainly the high osmotic value of certain 

 fungi which may grow upon strong sugar or nutrient solu- 



