BACTERIOLYSIS AND ALLIED PHENOMENA 183 



become disintegrated, or have at least performed an act of secretion 

 which they do not perform in the living blood. The conditions, 

 therefore, are not altogether natural. 



We are forced to rely to a large extent on indirect evidence, and 

 this, as far as it goes, is strongly in favour of Gengou's view. 



4. Ainley Walker's experiments dealt with the amount of com- 

 plement present in the successive amounts of serum squeezed out 

 from a clot, and showed that this gradually rises, the first few drops 

 containing but little, and the quantity gradually increasing until it 

 attains its maximum in about twenty-four hours. Other explana- 

 tions are possible, but it is at least probable that the cause of this 

 increase is the destruction of the leucocytes which is known to 

 occur during the process of coagulation, and that the formation of 

 complement is quite analogous with that of fibrin ferment. The 

 serum first formed is weak in complement, the destruction of the 

 leucocytes having only just commenced ; and it seems a fair 

 deduction that, if we could examine the plasma when no leucolysis 

 has occurred, we should find that it contains much less, or none 

 at all. 



This view is supported by Levaditi in a series of researches on 

 the fate of cholera vibrios injected into the circulatory system of 

 immunized guinea-pigs, care being taken to avoid as far as possible 

 the destruction of leucocytes. Under these circumstances he 

 finds that the Pfeiffer phenomenon does not take place, or does so 

 much more slowly ; the vibrios circulate in the blood for half an 

 hour or more without showing the least trace of granular trans- 

 formation, and are rapidly taken up by the leucocytes. In a 

 similar series of experiments on haemolysis he was able to prove 

 the existence of sensitized red corpuscles in the circulation, 

 although the animal did not present the least trace of haemo- 

 globinuria, and was of opinion that this was due to the absence of 

 free alexin in the plasrrr. The anaemia due to the injection of 

 haemolytic amboceptor he believes to be brought about by the 

 destruction of the red corpuscles within the macrophages of the 

 spleen. 



As a third item of indirect evidence we may quote the experi- 

 ments of Lubarsch and others, to the effect that an animal may be 

 killed by the intravenous injection of a smaller number of bacteria 

 (e.g., of anthrax) than are destroyed by a small quantity (i c.c. or 

 less) of serum. The simplest explanation is that the blood contains 

 an abundance of immune body, and the failure of the defensive 



