292 THE ROLE OF AGGLUTINATION IN IMMUNITY, 



Stern, who ascribed it to the production of the agglutinable 

 substance being temporarily in abeyance. Walker found the 

 same loss of agglutinating power in races recently isolated from 

 stools and grown in a mixture of immune serum and bouillon. 

 This was said to have been caused by a weakening of the receptors 

 of the bacteria through contact with the specific agglutinin. 

 Bail noted the insensibility of bacteria introduced into the peri- 

 toneum, and explained it as being due not to the production of a 

 non-agglutinable race but to a linking of the agglutinin-seizing 

 receptors of the bacteria with the byproducts [Abbauproducte] 

 of the agglutinin, which he designated as agglutinophores. This 

 insensibility was lost in the first subculture. Kirstein traces 

 the indifference to agglutinin to the loss of the mobile, aggluti- 

 nophore group of the agglutinin molecule. 



The insensibility of bacteria grown in the presence of agglutinin 

 to the further action of agglutinin might be better explained 

 than by the invention of new terms by considering the mechanism 

 of ao-glutination. The ao^fdutinable substance which is formed 

 by the bacterial protoplasm saturates the cell and exudes through 

 the membranes. If the agglutinin is more diffusible than the 

 agglutinable substance, as it very probably is, it will diffuse into 

 the membranes of the developing cell before the agglutinable 

 substance can diffuse out, and the reaction will take place in or 

 within the membrane. The precipitate formed in this place will 

 undoubtedly hinder the further diffusion of the agglutinable sub- 

 stance, so that the bacteria will be incapable of reacting to more 

 agglutinin, and the Gruber-Widal reaction will fail. When, 

 however, these bacteria are cultivated in the absence of agglutinin, 

 the diffusion-hindering layer of agglutinated substance will, by 

 the increase of the cells, become so attenuated that the agglutin- 

 able substance will once more diffuse out and the reaction will 

 be obtained. 



In a previous paper* I discussed, inter alia, the mechanical 

 swallowing or englobing of microbes by the mobile leucocytes, 



* This volume, cnitca p.lSS. 



