﻿76 FREEB. 



General considerations of the broader phenomena of immunity and 

 some more special analysis of the production of immunity lead us to 

 a chemical view of the question, and we are then brought to the con- 

 clusion that there must exist certain types or groups of complex sub- 

 stances which, coming in contact with the introduced cells, cause their 

 destruction. All investigators are agreed that, no matter how these 

 chemical substances have their origin, whether in the conglomerate of cells 

 which go to make up the body, or in certain special ones, such as the 

 leucocytes, once they are free in the circulation they can unite with the 

 introduced cell and can be removed by it. That this is not a phenomenon 

 of adsorption is proved by the fact that there is selective absorption of 

 the immune bodies or of the toxins by a cell, where two or more of the 

 former are present. All investigators also are agreed that, once the 

 immune substance is fixed by the cell, then the additional action of 

 another body or in the ease of the toxin, a chemical group therein present, 

 is necessary to cause the final destruction of the foreign organic complex. 

 As to the nature of this last mode of action, opinions differ. 



If we come to consider the actual relative mass of a toxin which 

 suffices to cause the death of an individual, or the actual relative mass of 

 a haemolytic immune bod}' as compared with that of the corpuscles which 

 it destro3'S, we are forced to the conclusion that the masses of the 

 reactive bodies are extremely small as compared with those of the cells 

 which they destroy. In an immune serum we have water, salts, fibrin, 

 globulin and in short a great proportion of substances which can not be 

 immune bodies, and this fact must be taken into consideration when we 

 regard the actual quantities of these substances present, but, on the 

 other hand, the cell to be destroyed must act as a whole; that is, for 

 example, if the process of destruction is one of hydrolysis, then the 

 hydrolytic action must disintegrate the whole cell. A guinea pig of 

 300 grams is killed by 0.0025 cubic centimeter or by approximately 10""' 

 times its mass of diphtheria toxin, a horse by 0.3 cubic centimeter of 

 tetanus and a mouse by l 10 " 7 gram; 2.8 1(H; gram of tarantula can com- 

 pletely dissolve 200,000,000 red blood corpuscles of the rat. It is true 

 that we can not actually determine, in a given case, just what mass of 

 cells is thrown out of function by a given amount of reagent and just 

 how many cells it is necessary profoundly to disturb before serious 

 consequences result to an organism, and in this respect reactions in vitro 

 give us little aid, as here we are not acting under normal conditions 

 of life, and we are also ignorant of the relation between the actual 

 weights of reagents employed. These studies are radically different from 

 the ordinary chemical ones, where the stoechiometric relations can ac- 

 curately be followed. 



However, the apparent disproportion between the mass of the reagent 

 which causes the disintegration of the cells and the probable mass of the 



