﻿IMMUNITY RESEARCH. 359 



which the animal exhibits marked hypersusceptibility to fresh inoculations 

 of the germ. He also states that anti-aggressin immunity is one of the 

 oldest methods of immunization, although its essentials were never before 

 understood. He claims that the experiments of Wassermann, Ostertag 

 and Citron with vaccination with suitably weakened bacilli, is nothing 

 but a modified form of Pasteur's immunization, and adds: "We consider 

 Pasteur immunity as the only true immunity, but it is nothing else than 

 an aggressin immunity. This is shown by its not having a high content 

 in anti-bodies." 



A review of the work both for and against aggressins leaves it ques- 

 tionable whether Bail and his school have made any real contribution 

 to bacteriology or immunity. It is by no means an easy matter, in many 

 cases, to obtain a clear idea, of their meaning, but some of the phenomena, 

 which they describe as aggressive in nature, can hardly be due to any 

 single cause and are probably to be explained by considering together a 

 series of processes in the bacteria and another series in the infected host. 

 Their claim that their aggressins are newly described substances has been 

 nearly overthrown and most of the characteristics have been found under 

 other conditions. As to the newness of anti-aggressin immunity, all 

 doubt is set at rest by Bail's statement that it is the same as Pasteur's 

 immunity. 



The lessons to be learned from the aggressin work are not new; the 

 same lessons are being taught by the workers upon opsonins and endo- 

 toxins, and they are : 



1. That there are very great differences in activity between otherwise 

 apparently identical strains of a species of bacterium; 2. That bacteria 

 undergo some important alteration when transferred from a sajorophytic 

 to a parasitic existence ; 3. That there are marked differences in the 

 reactions occurring in various species of bacteria after they are inoculated 

 into animals; 4. That the phenomena of agglutination, bacteriolysis or 

 phagocytosis do not separately afford an explanation of anti-infectious 

 immunity; 5. That the products of bacterial metabolism are numerous 

 and differ among themselves, and that the products differ according to 

 the pathogenicity of the bacterial strain. 



LITERATURE. 

 I. DEFLECTION OF COMPLEMENT. 



( 1 ) Axamit, Oskar : Gentrbl. f. Bakteriol. Orig. ( 190C ) XLII, 349. 



(2) Bauer, J.: Berl. Klin. Wchnsch. (1906) XLIII, 711. 



(3) Bordet, J.: Ann. d. VInst. Pasteur (1900) XIV, 257. 



(4) Bordet, J.: Berl. Klin. Wchnsch. (1906) XLIII, 17. 



(5) Bordet, J., and Gengou: Ann. d. VInst. Pasteur (1901) XV, p. 289. 



(6) Bruck, C: Deutsche med. Wchnsch. (1906) XXXII, 945. 



(7) Bruck, C: Ibid., 1368. 



