460 STUDIES IN IMMUNITY. 



before the corpuscles are added, only slight effects are produced. 

 If the fixation of the alexin on the corpuscles is brought about, 

 and they are then washed and subsequently subjected to the con- 

 glutinin, they are clumped but not hemolyzed.* The effects vary 

 markedly, according to the modus operandi, although the sub- 

 stances concerned remain the same. This is not surprising, for 

 we find similar examples throughout the phenomena of molecular 

 adhesion. Toxin and antitoxin when mixed in constant pro- 

 portions can, as we know, furnish complexes endowed with differ- 

 ent properties depending on whether they are added to one another 

 all at once, or in divided doses. In the serum diagnosis of syphilis, 

 for example, the slightest details in the preparation of the liver 

 extract is of importance. Sachs and Rondoni have found, for 

 example, that their results vary in accordance with whether their 

 concentrated alcoholic extract of liver is diluted with salt solu- 

 tion rapidly or slowly. It is conceivable, as these authors note, 

 that the active substance may be carried to different states of 

 colloidal division in accordance with these varying conditions, 

 and that differences of a physical nature correspond to the various 

 results in the energy of alexin adsorption. 



The physical condition of the conglutinin would seem, likewise, 

 to have a distinct influence on the result of the phenomenon. On 

 dialyzing bovine serum, 56 degrees, we obtain by centrifugalization 

 a supernatant fluid and a precipitate, the properties of which vary, 

 although they both contain conglutinin. On adding sufficient 

 sodium chlorid to reestablish the primitive tonicity, we find that 

 the supernatant fluid, when added to fresh horse serum, hemolyzes 

 guinea-pig corpuscles better than it conglutinates them.f The 

 precipitate gives the opposite result. When washed in distilled 

 water and shaken in salt solution, this precipitate dissolves only 

 partially; a cloudy fluid is obtained, which, on the addition of fresh 

 horse serum, agglutinates guinea-pig corpuscles energetically, but 

 hemolyzes them poorly. A mixture of the supernatant fluid and 



* Several examples of this fact have been noted in the articles of Bordet and 

 Gay and of Sachs and Bauer. 



t In certain cases, however, this fluid may give agglutination without hemolysis 

 as does heated bovine serum. This occurs when such a fluid is added to guinea- 

 pig corpuscles that have been previously subjected to fresh horse serum and 

 subsequently washed. 



