246 SOAPS AND PROTEINS 



plasmic derivatives which have a greater capacity for swelling 

 have also a mvater tendency to " go into solution." The ////m/x 

 ///(// make for (edema make aho, therefore, for the appearance of 

 protein (" albumin ") in the surrounding medium. The swollen 

 kidney in nephritis therefore yields albumin to the urine (albumin- 

 uria); the cedematous brain or spinal cord makes the protein 

 content of the spinal fluid go up; etc. 



3 



In association with these changes in the direction of increased 

 swelling and increased solubility, or decreased swelling and 

 decreased solubility, it is well to carry in mind a third type of 

 change to be considered whenever salt in rather high concentra- 

 tion is added to protoplasm and when the possibilities for chemical 

 reaction between the salt and the protoplasm are practically 



zero. The change about to be de- 

 scribed scarcely appears when the 

 normal (relatively dry) cell is up for 

 consideration; it may be prominent 



0ol } o" when the cell is cedematous (or prac- 

 o^^o o tically liquid). When a chemically 

 non-active salt is applied to protoplasm 

 B in relatively high concentration it tends 



FIGURE 114 ^ shrink the normal cell (see A of 



Fig. 114) concentrically; when mixed 



with a more liquid protoplasm the salt particles unite with water 

 within the protoplasmic mass (see B of Fig. 114). Dehydration 

 of the (protein) colloids of the cell occurs in both instances, but 

 volume change (in the sense of a decrease) may not appear in the 

 second. 



The matter is of much importance in the analysis of tho princi- 

 ples which must guide us in the treatment of oedema. As so 

 often insisted, all salts, including sodium chlorid, decrease the 

 hydration capacity of a protein in the presence of an acid and 

 for this reason should be administered in as high a concent ra lion 

 as possible to the cedematous individual. It has, however, been 

 insisted by various clinicians that the administration of salts 

 (especially sodium chlorid) does not decrease, but may actually 

 increase oedema. While many of the observations intended to 



