4 PROPERTIES OF H^MOLYTIC SERA 



stable substance ; it may remain practically unchanged in 

 amount for several months when kept in a sterile condition 

 in the dark at ordinary room temperature. The several 

 immune sera are conveniently designated by placing first 

 the name of the animal immunized and then the name of 

 the animal whose corpuscles have been injected ; thus a 

 haemolytic serum stated as rabbit v. ox signifies the serum 

 of a rabbit immunised against ox's corpuscles. As von 

 Dungern showed, in the process of immunization the amount 

 of complement does not increase, and, accordingly, the haemo- 

 lytic dose of the fresh serum may not represent the richness in 

 immune-body, owing to the lack of sufficient complement. 

 Accordingly, the ordinary procedure is to destroy the comple- 

 ment by heating, as above described, and then to reactivate the 

 immune-body by fresh normal serum, say of a guinea-pig or 

 rabbit. A preliminary procedure is to test the hsemolytic dose 

 of the immune-body, which, as is shown below (p. 7), varies 

 with different complements. In the case of the anti-ox serum 

 this is conveniently done with the aid of rabbit's comple- 

 ment (normal serum) as this has no action on the ox's 

 corpuscles. In the case of sera which have some natural 

 lytic action on ox's corpuscles, e.g. guinea-pig's serum, 

 the natural immune-body must of course be removed by 

 treating the serum with ox's corpuscles at C., before the 

 dose of the artificial immune-body can be ascertained. In 

 some instances, however, it is not possible to remove the 

 normal haemolytic property from a serum by treating it 

 with the corresponding corpuscles at C. (vide p. 72). 



A series of tubes is prepared, each containing the test amount 

 of suspension of red corpuscles, namely, 5 per cent, in 8 per 

 cent, solution of sodium chloride, the corpuscles having 

 been carefully washed to free them of serum. To each tube 

 more than the amount of complement necessary to produce 

 lysis is added, and then to the tubes in series different 

 amounts of immune-body, along with sufficient -8 per cent. 



