222 COLLOIDS IN BIOLOGY AND MEDICINE 



stant. Only the swelling of the nonassimilated reserve substance is 

 variable. This view, it seems to me, receives its chief support from 

 the findings of H. W. FISCHER and P. JENSEN* on muscle, which is 

 treated more thoroughly on page 291. According to their findings, 

 water occurs in muscle in two phases. One has a constant value 

 and is closely associated with the viability of muscle (conditioned by 

 the integral muscle protoplasm). The other phase varies in the ex- 

 ercising muscle and is only loosely bound (water of swelling of the 

 reserve material). 



Besides these factors of swelling which are inherent in the organ 

 colloids under consideration, there are others which are to a certain 

 extent impressed from without. The natural salt content as well as 

 the products of metabolism, especially the acids, are determinative of 

 the swelling of a tissue. Acid formation in an organ (e.g., CO 2 or lactic 

 acid in active muscle; CO2 in blood corpuscles) increases its swell- 

 ing capacity. If we observe that the potassium salts predominate in 

 one organ, and in others, the sodium salts, or even that there is an 

 accumulation of salts in a certain portion of a single cell, we may 

 conclude from that alone, that the water content also depends upon 

 such concentration. Potassium salts increase swelling; Ca salts 

 deplete (E. WIDMARK*), and according to R. CHIARI and JANUSCHKE 

 inhibit exudation. 



When the loss of water is very great (cholera, infant diarrhoeas), 

 there is an increase of potassium salts and phosphates in the urine. 

 From this it may be assumed that Na salts replace the K salts of 

 the muscles, and at the same time water is given off. According to 

 E. PRiBRAM,* 2 this occurs in order to protect more vital organs, espe- 

 cially the brain, from loss of water. 



Little is known concerning swelling from a biological point of 

 view. On this account, an observation of H. PAUL* seems especially 

 noteworthy. He pointed out in the case of peat mosses that the high 

 moor sphagnum is able to absorb much more water than the low moor 

 sphagnum. For example, sphagnum molluscum absorbs 27 times, and 

 sphagnum platyphyllum absorbs 16 times its dry weight of water. 

 In the same paper we find that the high moor sphagnum contains 

 much more acid than the low moor sphagnum, and that the former 

 are much more sensitive than the latter to the action of alkalis, lime 

 and salt. From this it seems to me we may certainly infer that 

 swelling of high moor sphagnum is greater than that of low moor 

 sphagnum because of its greater acidity, and that the damage it 

 suffers from salts, etc., may be attributed to the alteration in its 

 normal condition of swelling. 



We shall see that abnormal accumulation of acid in the tissues 



