AXD EHULWH'S THEORY. 359 



cytosis would seem to be of prime importance in 

 the first group, and the antitoxic and bactericidal 

 power of the serum in the second. 



Investigations from various sources render un- 

 questionable the value of phagocytosis in certain 

 infections, and of particular significance is the 

 work concerning opsonins which was referred to in 

 the preceding chapter. From this work it follows 

 that even for the phagocytic destruction of bac- 

 teria the serum contains properties which are of 

 essential importance. This appears of all the more 

 importance from the fact that immunization with 

 at least some micro-organisms (streptococcus, 

 staphylococcus) causes an increase in opsonins or 

 bacteriotropic substances. 



The accompanying illustration, with some modi- 

 fications, is taken from "Ehrlich's Seitenketten- 

 theorie," by Ludvig Aschoff. The cell used for 

 immunization is assumed to be a cell which will 

 cause the formation of antitoxin, agglutinin or 

 precipitin, and bactericidal amboceptors; the 

 diphtheria bacillus is such an organism, consider- 

 ing toxin as one of the receptors of the bacillus. 

 This means that the bacillus is able to cause the 

 overproduction of all three types of receptors. The 

 illustration, however, is on the basis of a hypo- 

 thetical cell (p. 360). 



A list of immunizing bodies, their anti-bodies, 

 and synonyms for complement and amboceptor, 

 is also appended (p. 361). 



