184 THE PRINCIPLES OF IMMUNOLOGY 



munization are overproduced and become free in the blood. Other 

 investigations, particularly those of Landsteiner and von Eisler, indicate 

 that the cell lipoids play a part in the union with complement. . The 

 material extracted from the cells by petroleum ether was found to be 

 definitely anti-hemolytic and furthermore this was especially true if 

 the cells used in hemolysis were from the same species as the lipoidal 

 extracts. Landsteiner and von Eisler demonstrated in addition that 

 cells treated with fat-dissolving agents were less susceptible to 

 hemolysis than normal cells. They suggested the possibility that the 

 fixing substance may be a lipoid protein combination. Bang and 

 Forssman extracted cells with ether and found that an acetone soluble 

 material could be recovered that was definitely anti-complementary. 

 Dantivitz and Landsteiner confirmed this but found in addition that the 

 fraction remaining in the ether, the acetone insoluble fraction, could 

 fix normal amboceptor but not immune amboceptors. Thus it will be 

 seen that the finer details of the anti-hemolytic powers of lipoidal 

 extracts are still unsettled. As to the anti-complementary action of bac- 

 terial extracts Zinsser suggests that it may be non-specific and com- 

 parable to the anti-complementary activity, mentioned in the previous 

 paragraph, of such inert substances as kaolin and quartz sand. 



The body fluids of importance in this connection are the tissue 

 juices, certain pathological exudates and more particularly the blood 

 serum. Camus and Gley found that a normal hemolysin may be in- 

 hibited by the addition of a similar serum which had been inactivated. 

 Miiller showed that a heated serum may inhibit the activity of other 

 sera, and concluded that this was due to an anti-complementary activity. 

 Extreme instances of this action have been reported by Kenneway 

 and Wright. Muir and Browning demonstrated that inactivated sera 

 homologous with those used as complement were more strongly anti- 

 complementary than heterologous sera. They concluded that the action 

 was due to the presence in the heated sera of complementoid which, 

 at least partly, excluded the complement from union with the ambo- 

 ceptor. Bordet and Gay found that a sufficient dilution of inactivated 

 sera removed the anti-complementary action and therefore consider 

 concentration of the serum a most important factor. This would indi- 

 cate that the inhibition is, in general, against the reaction, although 

 Sachs offers the suggestion that the dilution provides for a dissociation 

 of complement and anti-complement. More proof than is now at hand 

 is necessary in order to admit the existence of an anti-complement in 

 the sense in which Sachs uses the term Of great importance is the 

 work of Noguchi, who found that whereas heating the serum to 56 C. 

 permits of the demonstration of anti-lytic powers, a temperature of 

 70 C. considerably augments this activity. Noguchi was able to extract 

 from both serum and cells by means of ether a substance, highly ther- 

 mostable (90 C.), which exhibited the same anti-lytic properties 

 as the serum. The removal of the ether extract left the serum free 

 from anti-lytic activity. He named the substance " protectin " and 

 believed it to be the source of the inhibiting action of serum. Noguchi's 



