SOAPS, PROTEIN DERIVATIVES AND TISSUES 237 



The introduction of magnesium or calcium into protoplasm 

 leads, on the other hand, to a " drying out " of the protoplasmic 

 mass. While small amounts of these elements are necessary 

 to maintain protoplasm in its normal state, larger ones begin 

 to show a distinctly " poisonous " action. Such poisonous effect, 

 with corresponding dehydration of the tissues, jumps enormously 

 when salts of iron, silver, mercury or lead are used in pharma- 

 cological practice; hence the need of administering these sub- 

 stances in very small amounts, in medicine, if their use. is not 

 to be pushed beyond the " physiological limit." 



In the case of the heavier metals, the above considerations 

 lead us to the obvious conclusion that these act as poisons to 

 protoplasm because they unite with protoplasm to form compounds 

 more sparsely hydratable than normal protoplasm. In pathol- 

 ogy and medical practice the formation of such heavy metal 

 protoplasmic compounds is generally considered to constitute 

 an irreversible change and the affected protoplasm is commonly 

 adjudged necrotic or dead. The mere fact, however, that indi- 

 viduals poisoned by any of the heavy metals do occasionally 

 recover already indicates that such a conclusion overstates the 

 facts; it was learned, moreover, in considering the colloid-chemical 

 behavior of the analogous heavy metal soaps, that these could 

 be converted into light metal soaps. We wish now to show that 

 the heavy metal proteinates with their low hydration capacities can 

 also be converted into the more highly hydratable lighter metal pro- 

 teinates and that, as the latter are formed, colloid-chemical restitu- 

 tion to the condition which more nearly approximates the physio- 

 logical state of protoplasm may be obtained. Before pointing 

 out the obvious theory of intoxication and detoxication to which 

 \\\}< fact leads, some experiments of ROBERT A. KEHOE * must 

 be detailed. 



2. Experiments on the Conversion of Heavy Metal Proteinates 

 into Light Metal Proteinates 



A measured amount (5 cc.) of a viscid gelatin (2 grams in 



100 cc. water) was gently stirred together with an equal volume 



of distillril water or an equal volume of m/500 silver nitrate. 



The appearance of five tubes forty-eight hours after being thus 



1 ROBERT A. KEHOB: Jour. Lab. and Clin. Med., 6, 443 (1920). 



