TOXIN AND ANTITOXIN 125 



When we consider the invariable production of a specific anti- 

 toxin in response to the treatment of an animal with a toxin it is 

 but natural that Buchner and others should have at first assumed 

 that the antitoxin is, in each case, a product obtained by the action 

 of the body tissues from the toxin itself. While difficult to refute 

 at a time when little was known of the laws of antitoxin production 

 and of quantitative relationships, such an assumption is entirely un- 

 tenable in the light of more recent knowledge. We now know that 

 such a simple conversion of toxin into antitoxin cannot explain the 

 phenomenon because the amount of antitoxin incited in the immu- 

 nized animal is out of all proportion great in comparison with the 

 amount of toxin injected. Thus Knorr 28 has found that 100,000 

 units of antitoxin may be produced by the injection of the toxin 

 equivalent of one unit. Moreover the discovery by Salomonsen and 

 Madsen 29 that pilocarpin injections will increase the amount of 

 antitoxin produced by an animal distinctly pointed to the likelihood 

 of the participation of the general physiological activities of an 

 immunized subject in the production of antibodies. Unquestionable 

 proof of this was also brought by the experiments of Roux and Vail- 

 lard, 30 in which antitoxin production in immunized animals con- 

 tinued even after the entire volume of blood had been removed by 

 repeated bleeding. This observation points distinctly to the direct 

 secretion of antibodies by the tissue cell, in the nature of what has 

 been termed by Roux 31 an "internal secretion. 7 ' And it is this 

 activity of the body cell in the production of antibodies which forms 

 the fundamental premise from which the now classical "Side-Chain 

 Theory" of Ehrlich takes its departure. 



In order to approach this theory logically it will be of advantage 

 to consider briefly the general subject of the assimilation of food- 

 stuffs and other substances distributed by the circulation to the cells 

 of the animal body. For, as Ehrlich has expressed it, "The Reac- 

 tions of Immunity, after all, represent only a repetition of the 

 processes of normal metabolism, and their apparently wonderful 

 adjustment to new conditions is only another phase of 'Ur alter 

 Protoplasma Weisheit.' " 32 It is impossible to conceive the nutri- 

 tion of body cells without assuming that the assimilable nutritive 

 substances come into physical and, eventually, chemical relationship 

 with the protoplasm of the nourished cell. Considering the large 

 variety of substances which may thus be brought into contact with 

 cells in the course of normal and abnormal metabolism, the body cell, 



28 Knorr. Munch, med. Woch., 1898, pp. 321, 362. 



29 Salomonsen and Madsen. Ann. de I'Inst. Past., Vol. 12, 1898. 



30 Roux and Vaillard. Ann. de I'Inst. Past., Vol. 7, 1893. 



31 Roux. Ref . in Semaine Medicale, 1899. 



32 Ehrlich. Introduction to "Gesammelten Arbeiten," Berlin, Hirsch- 

 wald, 1904. 



