Physiology of Pathogenic Microbes. 73 



ocytes, as a result of the reaction whicli naturally 

 occurs on contact with foreign bodies, issue from the 

 vessels and take advantage of the situation. 



The bactericidal state, therefore, enfeebles the viru- 

 lent microbes, which are then overcome and removed 

 by the phagocytes. 



Immunity being in some way fixed in the anatomi- 

 cal elements, one can understand its persistence and 

 the possibility of its hereditary transmission. In 

 natural immunity or the refractory condition the 

 bactericidal proj^erty docs not appear to have, at 

 least in certain cases, the same importance as in ac- 

 quired immunity. Indeed, the blood of an individual 

 refractory to a given microbe can serve perfectly for 

 the artificial culture of this microbe. iNTevertheless, 

 too much importance should not be attached to this 

 fact. We shall see, later, that the blood is always 

 more or less bactericidal, but that this faculty disap- 

 pears shortly after its removal from the vessels. The 

 bactericidal property of the blood, therefore, depends, 

 without doubt, upon its contact with the living tis- 

 sues, hence we can form no accurate estimate of this 

 condition of the blood contained in the vessels of the 

 organism by comparing it with the same fluid outside 

 of the vessels. 



We know, again, that natural immunity results, in 

 the case of certain microbes, on account of the tem- 

 perature of the organism being either too high or too 

 low; it may also, as M. Arloing has demonstrated, 

 be the result of a natural insusceptibility of the or- 

 ganism to the action of the amorphous products se- 

 creted by the microbes. 



