198 COLLOIDS IN BIOLOGY AND MEDICINE 



A. The Distribution of Immune Substances Between 

 Suspensions and Solvent. 



Bacteria and blood corpuscles form suspensions which to a greater 

 or less extent are able to attract to themselves immune substances. 

 It is fortunate for the study of these phenomena that many experi- 

 ments have been preformed upon the adsorption of inorganic sus- 

 pensions (kaolin, charcoal, ferric hydroxid gel, etc.) from solutions 

 of known composition. For comparison many investigators have per- 

 formed appropriate experiments on toxins and immune substances. 



Adsorption by Means of Inorganic Suspensions and Hydrogels. 

 A sign of adsorption is a strong withdrawal of a dissolved substance 

 from dilute solutions and a relatively smaller withdrawal from such 

 as are more concentrated. This requires extensive quantitative inves- 

 tigation with solutions of different concentration. Unfortunately, 

 there are but few such experiments published. It may, however, be 

 deduced from the results of some of these experiments that an ad- 

 sorption curve is actually involved. 



Even W. Roux and YERSIN* found that calcium phosphate, 

 aluminum hydroxid and bone black removed some poison from a 

 solution of diphtheria toxin, but that the solution was never entirely 

 detoxicated. W. BILTZ, H. MUCH and C. SIEBERT* shook gels of 

 iron oxid, chromium oxid and zirconium oxid, among others, with 

 tetanus and diphtheria toxin, tetanolysin and a bactericidal horse 

 serum. They determined a diminution in the activity of the respec- 

 tive solutions, and that for the same quantity of hydrogel, the 

 diminution by activity was frequently more marked for dilute than 

 for concentrated solutions. Occasionally complete fixation or destruc- 

 tion occurred, e.g., in the case of typhoid agglutinin. H. BECHHOLD* 4 

 found that arachnolysin and staphylolysin were never completely re- 

 moved from solution by formol-gelatin or cellulose. K. LAND- 

 STEINER and his pupils shook tetanus toxin with kaolin, protagon, 

 cholesterin, palmitic acid, stearic acid and lecithin; a poisonous re- 

 siduum was always discovered in the solution. 



Since complement may be removed from a solution by various sus- 

 pensions (for literature see H. SACHS), a mechanical adsorption is 

 probable. 



Specific Adsorption. 



Glancing at the entire literature on this question, we are con- 

 fronted with the great difference in adsorption capacity of the ad- 

 sorbents as well as of the adsorbed substances. Although tetanus 

 toxin is well adsorbed by kaolin, protagon, cholesterin, palmitic acid, 



