Historical sketch on Immunity 537 



by very many observers. The fact that the alexins are confined 

 within phagocytes has been confirmed by several observers, and has 

 received a very convincing proof from Gengou's experiments on the 

 comparative action of the serum and blood plasma against micro- 

 organisms. The existence of phagolysis, denied at first by some 

 observers, has been verified by others and can now no longer be * 

 doubted. 



The relations between the sensibilising substance and the phago- 

 cytes are less easily grasped than are those between the alexins and 

 the leucocytes. Nevertheless, the experiments made by Pfeiffer and ' 

 Marx 1 , have led these observers to recognise that the former arises 

 from the spleen, the lymphatic glands, and the bone marrow, that 

 is to say, organs which are pre-eminently phagocytic. This result 

 has been confirmed by Deutsch and must be regarded as definitely 

 settled. All the data collected in recent years have, therefore, 

 confirmed the view that the destruction of micro-organisms in 

 the refractory animal presents itself as a special example of their 

 absorption by formed elements. This truth was so fully recognised [561] 

 in our laboratory that the analogy between bacteriolysis and the 

 destruction of animal cells was looked upon as quite natural and 

 evident. Bordet had for some years past observed that the blood 

 serum of certain animals presented a marked analogy in its aggluti- 

 native property in regard to micro-organisms and in that against 

 red blood corpuscles. In 1898, studying the fate of the spirilla of 

 the goose in the peritoneal cavity of guinea-pigs (see Chapter vi), 

 I observed that these micro-organisms underwent the same changes 

 both within and outside the phagocyte; this fact appeared to me to 

 be in perfect harmony with the whole of our knowledge concerning 

 the absorption of formed elements and on intracellular digestion. 



Bordet 2 , prepared by his preceding researches on the agglutination 

 of the red blood corpuscles, set himself to study the fate of the red 

 corpuscles in the animal body. He easily established a close relation- 

 ship between the development of the bacteriolytic property and the 

 haemolytic power of the serum of animals prepared by repeated 

 injections of bacteria and of blood. His results were soon (January, 

 1899) confirmed by Ehrlich and Morgenroth 8 , who supplemented them 

 with the important statement that Bordet's sensibilising substance, or 



1 Ztschr.f. Hyg., Leipzig, 1898, Bd. xxvn, S. 272. 



2 Ann. de I'lnst. Pasteur, Paris, 1898, t xn, p. 688 ; 1899, t. xm, p. 273. 



3 Berl. klin. Wchnschr., 1899, S. 6. 



