SOAPS, PROTEIN DERIVATIVES AND TISSUES 215 



upon which such emphasis has been laid for the explanation of their 

 stability are only observable in relatively dilute systems; the ion 

 contents are not inherent to, or necessary for, the stabilization; they 

 are accidental accompaniments incident to the solution of some of the 

 basic and acidic proteins in the excess of water and their hydrolysis 

 with the production secondarily of an overplus of hydrogen or hydroxyl 

 ions. 



Evidence for the general truth of these contentions may be 

 found in the following experiments in which " neutral " globulin 

 in the presence of a constant volume of water is exposed to the 

 action of various neutral salts. As ordinarily put, such " neu- 

 tral " globulins are said to be " soluble " in dilute salt solutions. 

 To our minds, this is not true. The salts again react with the 

 neutral globulin to yield globulin derivatives of the general 

 formula base-protein-acid which, like the previously described 

 base-protein and protein-acid compounds, also have a higher 

 hydration capacity and a greater solubility in water than the 

 original globulin. 



Figs. 104, 105, 106, 107 and 108 reproduce photographically the 

 findings described in Table LXVIII. Obviously a hydration of 

 "neutral" globulin may be induced through the presence of various 

 neutral salts as readily as through the presence of alkalies or acids, 

 in other words, in the absence of any such hydroxyl or hydrogen 

 ion concentrations as are commonly alleged to be responsible for 

 such a result. It is not the neutral globulin which is hydrated, 

 but its salts. In the experiments just described, these are pro- 

 duced because globulin (like the lower fatty acids of the acetic 

 series) has sufficient chemical reactivity to unite with the products 

 of the hydrolysis of any neutral salt (acid and alkali). 



Table LXVIII and the figures again show (in analogy to the 

 similar soaps) that the potassium and sodium derivatives of glob- 

 ulin are sooner and more highly hydrated than the corresponding 

 magnesium and calcium derivatives (the contents of the tubes 

 holding the latter being not only less swollen but whiter). The. 

 mercury derivative is so little hydrated that it remains a prac- 

 tically anhydrous, leather-like mass in all the tubes. 



In order not to lengthen these pages unduly wilh protocols, it 

 may suffice merely to state that findings entirely similar i<> those 

 just described are obtainable with the neutral salts of the soluble 

 sulphates. 



