186 Chapter VII 



preparation of the serums. I therefore asked Gengou to devote his 

 attention to this particular point and to compare the bactericidal 

 power of exudations, rich in microphages, with that of others con- 

 taining many macrophages and also with the blood serum of the 

 same animals. Gengou 1 has carried out his experiments with remark- 

 able exactness and care, and as I have followed them closely I am in 

 a position to speak as to their extreme accuracy. 



In order to obtain exudations very rich in microphages Gengou 

 injected gluten-casein by Buchner's method into the pleural cavity 

 of dogs and rabbits. Usually at the end of 24 hours he was able to 

 collect a large quantity of fluid containing numerous leucocytes, almost 

 exclusively microphages. To obtain macrophagic exudations Gengou 

 injected washed red blood corpuscles of the guinea-pig into the pleural 

 cavity of his animals ; two days afterwards he withdrew from the 

 pleural cavity a very viscid fluid, containing, as regards formed 

 elements, macrophages almost exclusively. After isolation of the 

 leucocytes by centrifugalisation of the exudations, Gengou washed 

 the cells with physiological salt solution and then added to them 

 an equal volume of broth. This mixture was frozen by Buchner's 

 method, and was then submitted to a temperature of 37 C. Under 

 [197] these conditions the leucocytes, killed by cold, gave up to the fluid 

 their bactericidal substance. 



Studied in this way, the bactericidal power of the extract of micro- 

 phages showed itself always superior to that of the corresponding 

 blood serum. The greatest difference was observed in the dog, 

 where, as already mentioned in the preceding chapter, the serum 

 of the blood has no bactericidal property as regards the anthrax 

 bacillus, whilst the extract of microphages manifests this property 

 very strongly. The microphagic extract of the exudations of rabbits 

 was more active in the destruction of the bacilli of anthrax and 

 typhoid, Bacillus coll and the cholera vibrio, than was the blood serum. 



The result of these experiments leaves no room for doubt. The 

 microphages, collected in the aseptic exudations of the dog and 

 rabbit, contain more bactericidal substance than does the blood 

 serum of the same animals. Nor can there be a doubt that this 

 bactericidal substance is the same whether it appears in the micro- 

 phages or in the blood serum : in both cases it is destroyed by heating 

 to 65 C. and, in all other respects, it behaves in the same manner. 



1 Ann. de FInst. Pasteur, Paris, 1901, t xv, p. 68. 



