l8o ORIGIN OF COMPLEMENT 



many researches have appeared, the point at issue being whether 

 the alexin or complement is formed from the polynuclear leuco- 

 cytes (for there is no evidence pointing to the lymphocytes). 

 Some of the most important of these must be briefly summarized. 



1. Various observers have investigated the relation between 

 the number of leucocytes in a given fluid and the amount of 

 complementary action. Thus Bulloch, working with haemo- 

 complement, found its amount closely proportionate to the number 

 of polynuclear leucocytes. His figures are very convincing, and 

 the only alternative explanation of his results is that the injection 

 of any substance which stimulates leucocytosis stimulates at the 

 same time the hypothetical complement-producing organ or tissue. 

 Similar observations have been made under natural conditions 

 by Longcope, who found that in disease in man the occurrence 

 of hyperleucocytosis is accompanied by a rise in the amount of 

 complement. On the other hand, Guseff's investigations on 

 similar lines were entirely negative, and he was unable to trace 

 any parallelism between the two ; and Briscoe, dealing with 

 peritoneal fluids, arrived at a similar result. These results may 

 be taken as typical of the whole. A series of experiments by an 

 able worker is apparently conclusive in one direction, and appears 

 to establish the point beyond controversy, but is immediately met 

 with another on similar lines, pointing to a diametrically opposite 

 result. 



Other investigations on similar lines are those of Bordet, who 

 found that the oedema fluid poured out in passive congestion in 

 an immunized animal a fluid poor in cells contains immune 

 body, but no complement, and that the aqueous humour is entirely 

 devoid of both substances. This latter fact has been corroborated 

 by Levaditi, who adds that when, after tapping, the aqueous 

 humour becomes rich in leucocytes, it acquires alexin at the same 

 time. 



2. Many observers have attempted to prepare complement 

 from emulsions of polynuclear leucocytes, from bone-marrow, 

 or from lymphoid organs. The results have been diverse in the 

 extreme, and this diversity appears due in part to the fact that 

 substances other than true alexins or complement may cause, 

 or play some part in the causation of, both haemolysis and 

 bacteriolysis. In particular, we may refer to the important role 

 of lecithin and its allies in haemolysis, and possibly in the destruc- 

 tion of bacteria also. It is quite possible, for instance, that the 



