318 STUDIES IN IMMUNITY. 



that the saline concentration of the pericorpuscular zone is under 

 any condition sufficient to bring about a precipitate of the colloid 

 or of the suspension around the corpuscles. We have noted a fact 

 in our first article that answers this objection: we caused a diffusion 

 of all the substances that the corpuscles contain. For this pur- 

 pose we laked corpuscles with distilled water and then washed them 

 several times in 0.7 per cent salt solution. As a result of several 

 such washings we presumed that the saline tonicity of the strornata 

 and consequently of the pericorpuscular zone should not exceed 

 that of the fluid between the corpuscles, and that, consequently, 

 with such stromata we have to deal simply with the sodium chlorid 

 in salt solution. Such stromata as they contain no intracorpuscular 

 salts should not be agglutinable by a colloid or by a chemical sus- 

 pension. We find, however, that on adding CaFl 2 to such stromata 

 an agglutination takes place which is quite comparable with that 

 of red blood cells ; the CaFl 2 , moreover, may be replaced by barium 

 sulphate or by colloidal ferric hydroxide. 



We see no reason for supposing that the agglutination of stro- 

 mata by colloids and suspensions is to be explained in any different 

 way than that of red blood cells. In fact the agglutination of 

 stromata by such a suspension as CaFl 2 follows in all its details the 

 phenomena present in the agglutination of red blood cells. In 

 both instances the intensity of the agglutination depends on the 

 amount of CaFl 2 employed; the maximum agglutination occurring 

 with an optimal dose, a smaller or larger amount giving rise to less 

 agglutination. In each instance, moreover, the addition of a small 

 amount of serum prevents agglutination. The phenomena are 

 absolutely interchangeable, which shows, according to our opinion, 

 that in agglutination of corpuscles by a suspension the salts from 

 the corpuscles do not first flocculate with the suspensions in order 

 to bring about agglutination. The fundamental action takes place 

 between the albuminoid substances (stromata) of the corpuscles and 

 the suspensions in question.* 



* We find, indeed, that agglutination of stromata may be produced by barium 

 sulphate whether suspended in distilled water or in 2 per cent salt solution, and 

 it seems difficult to imagine that a suspension that is so little affected by elec- 

 trolytes should be influenced by the traces of salts that might come from the 

 stromata. Mangin and Henri have noted similar phenomena in the agglutination 



