224 



THE ANTIGEN-ANTIBODY REACTIONS 



The sensitized patches appeared to be sticky, not only for each other, but for non- 

 specific particles. No estimate of the degrees of stickiness is possible from an electron 



micrograph, but if we assume that the 

 non-specific and specific stickiness were 

 of the same order, the observation pro- 

 vides evidence in favovir of the two -stage 

 rather than the lattice hypothesis. 



Fig. 38. — Dark-ground photomicrograph 



of Salm. typhi aggregated by somatic 



antibodies. 



(From a photograph kindly supplied by 

 Dr. A. Pijper.) 



Fig. 39. — Dark-ground photomicrograph 



of Salm. typhi aggregated by 



Vi antibodies. 



(From a photograph kindly supplied by 

 Dr. A. Pijper.) 



In a mixture of a tobacco mosaic virus, having a particle width of 15 m[x, and its homo- 

 logous antibody, Anderson and Stanley (1941) demonstrated that, in antibody excess, 

 the increase in width of the virus particles was compatible with the hypothesis that highly 

 elongated rabbit antibody molecules, about 4 X 27 m//, were attached radially to the 

 surface of the antigen. The authors point out that electron micrographs of the aggregates 

 suggest a rough lattice formation. Such a resemblance is irrelevant in a consideration 

 of Marrack's hypothesis, in which " lattice " is used more in a crystaUographic, than in 

 a secular, sense of the term. 



The Lysis of Red Blood Cells. 



Althougli the original observations on the phenomenon of lysis were made 

 on bacteria, Bordet's demonstration that a similar reaction could be obtained 

 with red blood corpuscles, and the numerous and detailed investigations of Ehrlich 

 and his school into the interactions between red cells and their corresponding 

 antisera, turned the attention of the great majority of workers from bacteriolysis 

 to haemolysis ; and the greater part of our knowledge of the mechanism of lytic 

 reactions in general is based on the data obtained in studying the lysis of red cells. 

 For this reason we shall discuss haemolysis before considering the lysis of bacteria. 



It is not possible, in the space at our disposal, to give any account of the his- 

 torical development of our knowledge of this subject. Reference must be made 

 to textbooks dealing particularly with immunological reactions, or to the collected 

 papers of Bordet, and of Ehrlich, who have been the protagonists in this particular 

 controversy. The main facts, which are not in dispute, are as follows : 



The phenomenon of haemolysis consists in a laking of the red blood corpuscles, 

 that is, in a setting-free of their contained haemoglobin, and not in a true solution. 

 The cell stromata remain undissolved, though altered in size and shape, and 

 probably in other physical and chemical characteristics. 



As has already been noted, it was shown by Bordet (1898) that haemolytic sera, 

 like the bactericidal sera studied by Buchner, are inactivated by heating for 30 



