B act erioly sins 27 



The seat of origin of bacteriolytsins in corpore has been studied by a nrunber 

 of observers, and has been the subject of considerable discussion, for which reason 

 I shall not enter upon it here (see jMetchnikoff, 1901 ; Pfeiffer and Marx, 1898 ; 

 Deutsch, 1899 ; Wassermann, 1899 ; Romer, 1902 ; and the reviews of Ritchie, 

 1902 and Aschoff, 1902). According to Pick (1902, pp. 15—21) bacterioljsins arc 

 contained in the euglobulin fraction of serum, this being contrary to PfeifFcr and 

 Proskaiier (1896). 



That there is a diference i)i the specific bacteriolytic sera obtained from dif event 

 animals a])pears to be the case from the investigations of Sobernheini (1899), who 

 found that anti-anthrax serum (jl)tained from immunitied sheep was able to pi-otect 

 sheep but not rabbits. In this case we arc tlealing, not with an antitoxic serum but 

 with one whose action is antibacterial. As Ehrlich (Croonian Lect. 1900) notes, 

 Kitt had a precisely similar experience with symptomatic anthrax. It will be noted 

 that an analogous observation has been made with regard to the precipitins. 

 This would appear to be due to the complexity of bacteriolysins and i^recipitins as 

 compared with antitoxins, where no such differences have been noted. It may be 

 supposed that in reacting to a highly complex body the organism impresses 

 more of its own character upon the antibody which it evolves. 



Deptending upon the age of an animal, its blood corpuscles will behave differently 

 both to natural and artificial haemolysins. Thus Camus and Gley (1899, p. 779) 

 found the normal haeniolysin of eel serum to be markedly resisted by the corpuscles 

 of young rabbits, and Delezenne (x. 1900, p. 702) found the corpuscles of young 

 dogs to be much more resistant to the artificial haemolysins (for dog) than those 

 of adult animals. We shall see that the precipitins also give different reactions 

 with foetal and adult blood. 



The bacteriolysins to which reference has been made in the preceding pages 

 constitute a class of cytotoxins essentially similar to the haemolysins. They act 

 upon bacteria. Their presence in normal blood and various body fluids was 

 demonstrated by Nuttall (1888) j whereas artificial or specific bacteriolysins were 

 first demonstrated by Pfeiffer in animals innnunified with the cholera vibrio. 

 The work done on the bacteriolysins has been very extensive, but it is impossible 

 to enter into the subject here at all in detail. It will sufiice to say that the 

 specific bacteriolysins behave essentially as do the specific haemolysins, and that 

 they possess the same constitution. They are composed of a labile complement 

 (destroyed at 55" C, as I first showed for normal bacteriolysins) and of a stable 

 immime-body. The latter is" capable of conferring immunity, as was first shown 

 by Fraenkel and Sobernheini (1894, p. 154), on heated anti-cholera serum which had 

 lost its bactericidal properties. Wassermann (3, i. 1901) was able to neutralize the 

 complement by means of anti-comj^lement, the latter being specific and only capable 

 of binding one sort of complement. As in haemolytic sera, agglutinins may be 

 present together with lysins. Pfeiffer observed the agglutinin to disappear in 

 stored immune-sera (of goat and dog treated with B. typhosus) and the immune- 

 body to persist therein. Mertens (13, vi. 1901), who cites this unpublished 

 observation of Pfeiffer, was able to confirm it on cholera immune-serum 5 years old. 

 The existence of immune-bodies in anti-microbic sera has been also proved by 

 Bordet and Oengou (v. 1901) in experiments upon the blood of animals treated with 



