96 INFECTION AND RESISTANCE 



in some cases, has a primary toxicity per se ; and which is variously 

 distributed among the organs and tissues according to the biological 

 peculiarities of the particular micro-organism in question. This 

 general conception will become more clear as we analyze the phe- 

 nomena associated with the individual antibodies. It is, of course, 

 quite plausible as far as it refers to the phagocytic functions, or even 

 bacteriolytic and cytolytic phenomena. It has been less clear in 

 connection with the agglutinins and precipitins in which a direct de- 

 fensive or bacteria-destroying value is not apparent. However, in 

 our discussions of these phenomena we will have occasion to point out 

 many reasons for assuming that, even in these phenomena, there are 

 features which fall into direct correlation with the views we have 

 just expressed. 



The substances which possess antigenic properties that is, which 

 give rise to antibody production with the exception of a few isolator 

 and contested cases, are all of them protein in nature. Well-trained 

 chemists have exerted themselves to purify antigenic substances, 

 in attempts to determine the particular fractions of the complex 

 protein molecule upon which the antigenic properties depend. In 

 the course of such work a number of men claim to have obtained a 

 truly antigenic substance which no longer gave protein reactions. 

 The instance most frequently cited is Jacoby's 65 announcement of 

 a protein-free ricin. Jacoby worked with an apparently very impure 

 "Ausgangsmaterial" consisting of commercial ricin, which he di- 

 gested for five weeks in trypsin solution. At the end of this time he 

 obtained a ricin which still possessed the properties- of the original 

 castor-bean extract, but no longer gave protein reactions. His "puri- 

 fied ricin," however, was quickly destroyed by further trypsin diges- 

 tion, and more recent work by Osborne, Mendel, and Harris 66 ap- 

 pears to have fully refuted Jacoby's results. They found the purified 

 ricin identical with the coagulable albumin of the castor bean, and 

 found that tryptic digestion destroys the characteristic ricin prop- 

 erties. 



Less easily refuted have been the careful experiments of Ford 67 

 upon the active principle of a mushroom (Amanita pJialloides) and 

 upon that of the poison-ivy plant (Rhus toxicodendron) . These 

 substances, he claims, are non-protein. In the case of Amanita 

 phalloides Abel arid Ford 68 have shown it to be a glucosid, and 

 similar structure has been claimed for Ehus by Syme. 69 Yet with 

 both of these substances Ford has succeeded in producing specific 



65 Jacoby. Arch. f. exp. Path. u. Pharm., Vol. 46, 1901. 



66 Osborne, Mendel, and Harris. Am. Jour, of Physiol., 1905, Vol. 14. 



67 Ford. Jour, of Inf. Dis., Vol. 3, 1906; Vol. 4, 1907. 



68 Abel and Ford. Jour. Biol. Chem., 1907. 



69 Syme. Johns Hopkins Thesis, 1906. 



