FURTHER DEVELOPMENT OF KNOWLEDGE 171 



kind is that carried out by Gengou 13 in 1001. It was Gengou's 

 primary purpose to obtain the plasma of mammals in such a way 

 that no cell injury would occur. This he accomplished by special 

 methods in which coagulation was avoided without the addition of 

 foreign anticoagulants like hirudin, etc. His technique was, in 

 essence, as follows : He took the blood directly through a paraffined 

 cannula into tubes that had been coated with paraffin, and centrifu- 

 galized it at low temperatures until cell free. This plasma, taken 

 from the paraffin tubes, quickly clotted, and the material with which 

 the experiments were done actually consisted of blood serum. Upon 

 examining the serum so obtained, he found that it exerted practically 

 no bactericidal action. As a result of this investigation he claims 

 to have demonstrated the truth of Metchnikoff's contention that the 

 circulating blood plasma contains no alexin. 



If borne out, it is true that Gengou's results would very power- 

 fully support this theory, and for this reason a large number of ex- 

 periments have been made since then, with the same end in view. 



In all such investigations the technical procedures are extremely 

 difficult and, as Addis 14 has recently said, in our opinion quite cor- 

 rectly, it would be impossible to carry out bacteriolytic or hemolytic 

 experiments with mammalian paraffin plasma without obtaining 

 coagulation, and for this reason most of the writers who have re- 

 peated Gengou's experiments have worked, as did he, not with 

 plasma, but with serum. Falloise, 15 following Gengou's method 

 exactly, obtained results diametrically opposed to those of Gengou; 

 Schneider, 16 also with the same technique, failed to confirm Gengou's 

 results; Herman, 17 on the other hand, confirms Gengou. 



In order to overcome the technical difficulties encountered in 

 working with mammalian plasma a number of writers have more 

 recently experimented with bird blood, which, as is well known, 

 coagulates much more easily than does mammalian blood. Hewlett, 18 

 who worked with goose plasma and peptone plasma, could not con- 

 firm Gengou's results. Lambotte, 19 examining the plasma of chick- 

 ens, found no difference between the serum and plasma in their con- 

 tents of bactericidal alexin, as measured against cholera spirilla. 

 Von Dungern, working with fish plasma, obtained similarly negative 

 results, and recently Addis, in a careful comparative study of 

 chicken plasma, found no evidence of differences between plasma 

 and serum in either the bactericidal or the hemolytic alexin. As far 



13 Gengou. Ann. de I'Inst. Past., Vol. 15, 1901. 



14 Addis. Journ. of Inf. Dis., Vol. 10, 1912. 



15 Falloise. Bull, de I'Acad. Eoy. de Med,, 1905, p. 230. 



16 Schneider. Archiv f. Hyg., 1908, Vol. 65, p. 305. 



17 Herman. Bull, de I'Acad. Eoy. de Med., 1904, p. 157. 



18 Hewlett. Archiv f. exp. Path. u. Pharmk., 1903, Vol. 49, p. 307. 



19 Lambotte. Centralbl. /. Bakt., I, Orig., 1903, Vol. 34, p. 453. 



