BACTERIOLYS1NS AND HMMOLYSINS 49 



the serum of the guinea pig treated with cholera 

 bacilli transmits an increased solvent power only 

 for cholera bacilli, but not for any other species of 

 bacteria. The active substance of such a bacterio- 

 lytic immune serum Pfeiffer called a specific bac- 

 tericide. If we allow some of this specific cholera 

 immune serum to remain for some time outside of 

 the body, e.g. in a bottle, and then test it for 

 solvent properties against cholera bacilli, not in a 

 living body but in a test-tube, we shall find that its 

 power is almost nil. If we add to this serum in 

 the test-tube some fresh peritoneal exudate or 

 some other body fluid, such as serum of a normal, 

 untreated guinea pig, as Metchnikoff first did, we 

 find that this serum has now acquired the power 

 to rapidly dissolve cholera bacilli even in a test-tube. 

 Bordet, 1 in 1895, showed that in order for the specific 

 immune serum to dissolve bacilli in a test tube, 

 it is unnecessary to add fresh normal serum or 

 peritoneal fluid; but that immune serum freshly 

 drawn from the vein is able even under these cir- 

 cumstances to dissolve the bacilli. 



Haemolysis. Let us now turn for a moment to 

 the development of this subject along other lines. 

 If we go back to the time when blood transfusion 

 was first practised we find it stated that the bloods 

 of different animals transfused into man were more 

 or less directly injurious, and not capable of replac- 



1 Bordet, Annal. Inst. Pasteur, 1895. 



