( 145 ) 



defended with such admirable acumen and unflagging energy. 

 According to the same investigator, the part they play in the healthy 

 body is no less important. The only thing therefore which remains 

 to be done with regard to these cells, is to get a nearer insight into 

 their conditions of life; as yet scarcely anything is known on this 

 subject, a fact mentioned with regret by Metchnikoff, in the paper 

 he read last year before the students of the University of Amsterdam, 

 on : "Reactions phagocytaires" l ). 



The method of investigation employed by us was the following: 

 White corpuscles from the blood of a horse, after having been trans- 

 ported into various media, were brought into contact with carbon 

 and afterwards it was ascertained what percentage of the leucocytes 

 had taken up particles of carbon. This percentage was (he measure 

 for the degree of phagocytosis and gave the value of the influence 

 of various agents on that function of life. 



These calculations were based on the principle that the phagacytorian 

 power of the phagocytes present in a suspension is of unequal 

 extent ; i. e. the more detrimental the action of the agent is, the 

 smaller must be the number of phagocytes able to take up 

 carbon. 



Our selecting a neutral indiiferent substance of bacteria, had 

 its ground in the fear that otherwise our work would have become 

 too complicated. We here refer to the recently established fact 

 that most kinds of bacteria, before they can be taken up by 

 the phagocytes, must undergo a certain amount of preparation 2 ). 

 Hence it follows that not only will the intensity of phagocytosis 

 be influenced by the agent as such, but also by the degree of 

 preparation it has undergone. Another fact which had to be borne 

 in mind, is that the bacteria sometimes secrete poisons which have 

 an injurious eifect on the phagocytosis. 



') "Nous ne sommes qu'an debut. Lorsqu'on connaitra mieux la physiologie dss 

 phagocytes (the italics are ours) on cherchera des methodes pour augmenter l'activité 

 de ces elements dans la lutte contre les microbes et on cherchera d'autres pour 

 preserver contre l'altaque des phagocytes les cellules nobles de notre corps. En 

 poursuivant ce but, il faudra tenir compte de ce que les phagocytes sont non 

 seulement les destructeurs des microbes, mais qu'ils sont capables aussi de s'en- 

 corporer des poisons solubles et de les rendre inoffensifs. Leur röle n'en devient 

 que plus important." 



2 ) Wright and Douglas, Proceed, of the Royal Society 72, 1903, p. 357 and 

 later studies prepared under Wright. Further Hektoen and Rüdiger, Journ. of Infect, 

 diseases 2, 1905, p. 128 and other studies prepared under Hektoen. 



10* 



