206 COLLOIDS IN BIOLOGY AND MEDICINE 



have inferred from the following experiments of J. MORGENROTH and 



D. PANE.* 5 



I wish to call attention to one other property which is strongly 

 suggestive of colloids. J. MORGENROTH and D. PANE* heated 

 cobra venom in n/20 HC1 solution and determined its hemolytic 

 action immediately after cooling and neutralization. The hemolytic 

 activity induced by lecithin was greatly diminished but gradually 

 (after hours or days) resumed its original strength. It seems reason- 

 able to regard the gradual restoration of toxicity as phenomena of 

 "maturation" since the particles of the molecular dispersed cobra 

 hemolysin, gradually unite to larger agglomerations and thus ac- 

 quire greater adsorptive capacity. 



Colloid chemistry offers numerous similar examples; to mention 

 only the aging of dye solutions (hemotoxylin) which must occur pre- 

 vious to its utilization in histological stains. The same interpreta- 

 tion applies to the anologous observation upon the neurotoxin of 

 cobra venom. 



As a rule the union of antigen and immune substances is inhibited 

 both by H and by OH ions. Just as H and OH ions may break down 

 the union of toxin and antitoxin so may they dissolve the bonds 

 holding agglutinin to its substrate (HAHN and R. TROMMSDORF), or 

 either abrin or amboceptor to blood corpuscles. 



The influence of reaction on the action of hemolytic sera is told in 

 the researches of S. ABRAMOW, HECKER, L. VON LIEBERMANN, P. 

 RONDONI, H. SACHS and ALTMANN, L. MICHAELIS and SKWIRSKY (see 

 P. RONDONI* for bibliography). 



Under certain conditions hemolysis is hastened by slight acidity 

 and retarded by larger quantities of acids or by alkalis. 



The inhibiting action of alkali and to a less definite degree, of acid, 

 is evident in antigen-antibody combinations, as is revealed by com- 

 plement deviation (see p. 207). Its significance is also evident in the 

 WASSERMANN reaction. 



Addition of 1/1000 to 1/3200 normal NaOH may inhibit the reac- 

 tion in a strongly positive serum; similarly, a negatively reacting 

 (luetic serum) may give a strongly positive reaction after the addition 

 of 1/1000 to 1/2000 HC1 (H. SACHS and ALTMANN). 



The following findings favor the view that the physical fixation of 

 amboceptor by blood corpuscles is influenced by the reaction. By 

 means of alkali, the blood corpuscles may be prevented from com- 

 bining with the amboceptor; on the other hand amboceptor-laden 

 blood corpuscles may be deprived of amboceptor by alkalis, and 

 the amboceptor may be recovered in an active condition. The facts 

 for acids are not so obvious. 



