ii6 Immunity 



anchors them to the cells of organs. To formulate a general statement, the 

 capacity of a body to cause the production of antitoxin stands in inseparable 

 connection with the presence of a haptophore atomic group. In the formation 

 of antitoxin the toxophore group of the toxin molecule is, on the contrary, of 

 absolutely no moment. But the toxoid modification of the toxins, in which the 

 haptophore group of the toxin is retained, while the toxophore group has ceased 

 to be active, possesses the property of producing antitoxins. Indeed, in some 

 cases of extremely siisceptible animals, immunity can only be attained by means 

 of the toxoids, and not by the too strongly acting toxins." .... "The 

 symptoms of illness due to the action of the toxophore group, therefore, play no 

 part in the production of antitoxin." The effect of enzymes upon the organism 

 with the production of antibodies, and the "specific precipitins" caused by the 

 injection of milk, albumin, and peptones into animals may be looked uponas 

 "having their origin in the most widely diverse organs, and representing nothing 

 more than nutritive side-chains, which in the course of the normal nutritive 

 processes have been developed in excess and pushed off into the blood." 



"Much more complex than in the cases hitherto discussed are the conditions 

 when, instead of the relatively simple metabolic products of microbes, the living 

 micro-organisms themselves come to be considered, as in immunization against 

 cholera, typhoid, anthrax, swine-fever, and many other infectious diseases. 

 Thus there come into existence, alongside of the antitoxins produced as a result 

 of the action of the toxins, manifold other reaction products. This is because 

 the bacterium is a highly complicated living cell of which the solution in the 

 organism yields a great number of bodies of different nature, in consequence of 

 which a multitude of 'antikorper' are called into existence. Thus we see, as a 

 result of the injection of bacterial cultures, that there arise alongside of the 

 specific bacteriolysins, which dissolve the bacteria, other products, as, for example, 

 the 'coagulins' (Kraus, Bordet), i.e., substances which are able to cause the 

 precipitation of certain albuminous bodies contained in the culture fluid injected; 

 also the much-discussed agglutinins (Durham, Gruber, Pfeiffer), the antifer- 

 ments (von Diingern), and no doubt many other bodies which have not yet been 

 recognized. It is by no means unlikely that each of these reaction products 

 finds its origin in special cells of the body; on the other hand, it is quite likely 

 that the formation of any single one of these bodies is not of itself sufficient' to 

 confer immunity. Thus, in the case of the introduction of bacteria into the 

 body we have to do with a many-sided production of different forms of 'anti- 

 korper,' each of which is directed only against one definite quality or metabolic 

 product of the bacterial cell. Accordingly, in recent times, the practice of using 

 for the production of immunization definite toxic bodies isolated from the 

 bacterial cells has been more and more given up, and for this purpose it is now 

 regarded as important to employ the bacterial cells as intact as possible." . . . 

 "The most interesting and important substances arising during such an immuniz- 

 ing process are without doubt the bacteriolysins." .... " Belfanti and Car- 

 bone first discovered the remarkable fact that horses which had been treated 

 with the blood-corpuscles of rabbits contain in their serum constituents which 

 are poisonous for the rabbit, and for the rabbit only." . . . "Bordet showed 

 shortly thereafter that in, the case quoted there was present in the serum a 

 specific hemolysin which dissolved the corpuscles of the rabbit. He also proved 

 that these hemolysins — as had already been shown by Buchner and Baremberg 

 in the case of similarly acting bodies which are present in normal blood — lost 

 their solvent property on being maintained during half an hour at a temperature 

 of SS°C. Bordet added, further, a new fact, that the blood-solvent property 

 of those sera which had been deprived of solvent power by heat, the solvent 

 action could be restored if certain normal sera were added to them. By this 

 important observation an exact analogy was established with the facts of 

 bacteriolysis as elicited by the work of Pfeiffer, Metschnikoff, and Bordet." 



. . . "In collaboration with Dr. Morgenroth, I have sought in regard to this 

 question, for which hemolysis offered prospects favorable to experimentation, 

 to make clear the mechanism concerned in the action of these two compounds — 

 the stable, which may be designated 'immune body,' and the unstable, which 

 may be designated 'complement' — which acting together effect the solution of 

 the red blood-corpuscles. For this purpose, in the first place, solutions containing 

 either only the 'immune body' or only the ' complement ' were brought in contact 

 with suitable blood-corpuscles, and after separation of the fluid and the Corpuscles 



