172 THE BORDET-GENGOU PHENOMENON 



serum which had been exhausted by the action of cholera vibrio 8 

 had been added. The anti-amboceptor which thus appeared to 

 be present in normal serum seemed to be strictly specific ; a 

 serum which had been weakened by the action of cholera vibrios 

 had no action on antityphoid serum, and vice versa. 



Besredka attempted to explain these findings on the assumption 

 that " free receptors " passed from the bacteria into the normal 

 serum, and, when subsequently mixed with antiserum, combined 

 with it, and so prevented its union with the living bacteria. They 

 showed, in reply, that normal saline solution had no such action ; 

 but this is hardly conclusive, since receptors are dissolved from 

 the bacteria much less powerfully in normal saline than in serum. 



According to Sachs, who demonstrated a similar occurrence in 

 haemolysis, the inhibiting substance which actually occurs in the 

 serum is an anticomplement. Gay, however, believes that the 

 whole series of phenomena can be explained by the absorption of 

 the complements in a specific precipitate. Thus, in Sach's 

 experiment normal rabbit serum heated to 55 C. was treated with 

 sheep's corpuscles. It was then removed, and added to a mixture 

 of heated serum immune to sheep's corpuscles (obtained from a 

 rabbit treated with sheep's corpuscles), fresh guinea-pig's serum, 

 and sheep's corpuscles. No haemolysis occurred, as it did in the 

 control experiment, in which no " exhausted " normal serum had 

 been added. His explanation was that the normal serum con- 

 tained amboceptors which combined with sheep's corpuscles, 

 leaving other amboceptors which have a greater affinity for 

 complement than those combined with the corpuscles used as a 

 test. Gay's explanation (which is almost certainly the correct 

 one) is quite similar to Moreschi's explanation of the anti- 

 complements. He believes that the immune serum contains also 

 a precipitin to sheep's serum, and that in the " exhaustion " of the 

 heated normal serum by the sheep's corpuscles some sheep's 

 serum was added to it, the corpuscles in Sach's experiment not 

 having been thoroughly washed. Thus a serum precipitate was 

 formed, and the alexins or complements combined therewith, so 

 that no haemolysis occurred on the subsequent addition of sensitized 

 corpuscles. He showed that if thoroughly washed corpuscles 

 were used for the exhaustion the phenomenon did not occur, and 

 gives other experimental proof. 



Gay has also attempted to explain the process of deviation of 

 the complements in bacteriolysis (the Neisser-Wechsberg pheno- 



