244 SOAPS AND PROTEINS 



It is as different from the ordinary dilute solution as a " solution " 

 of water in phenol is different from one of phenol in water. 



The experiments detailed in the preceding pages also indicate 

 how the colloid-chemical nature of this hydrated protein colloid 

 which constitutes the physiological basis of life may be changed, 

 either from within or without, so as to give rise to the manifesta- 

 tions of physiology, or, when more accentuated, of pathology. 

 Through temporarily or more continuously acting factors, be they 

 mild or drastic in their action, the chemical character of protoplasm 

 is changed and depending upon the hydration and solution character- 

 istics of the new compounds formed, the physical state of the living 

 mass is also changed. 



In the list of the simpler changes which may thus be brought 

 about are those which give character to oedema and abnormal 

 water loss. The protoplasmic mass which in its " normal " state 

 has sucked up as much water as it can, is possessed of what the 

 physiologists call a normal water content or a normal turgor. 

 If, for any reason, a cell takes up more than this normal amount 

 of water, it becomes " cedematous." The botanists say that 

 the cell is then in a state of abnormally high turgor which, when 

 extreme, results in destruction of the cell or " plasmoptysis." 

 Obviously, anything which under physiological or pathological 

 conditions brings about such change in the colloid mass, which, 

 in other words, enables it to absorb such excessive amounts of 

 water may be listed as a " cause " of oedema or increased turgor. 



For this reason abnormal accumulations of acids or of alkalies 

 within a cell may be listed as causes for oedema, for these so act 

 upon the " normal " albumins of the cell as to convert them 

 into albuminates which have a higher hydration capacity. But 

 the amins, pyridin and urea also increase the hydration capacity 

 of proteins (though in a different way) so they, too, are in pro- 

 portion to their activity, " causes " for oedema. Or when one 

 basic or acid radical is substituted for another in the normal 

 protoplasm this may be a cause for oedema; for ammonium or 

 potassium proteinates are more hydratable than sodium or mag- 

 nesium proteinates, and protein chlorid swells more than protein 



toplasm is subjected to drying out, to the action of water, or to the action of 

 analytical agents, is to our minds true also of many other components held to 

 be preexistent and "dissolved" in living matter. Alkaloids certainly do 

 not exist as such in normal protoplasm they are split off through the methods 

 used to isolate them as JOHN URI LLOYD has so often insisted. 



