VACCINATION. 379 



one organism in the body neutralizing the action of another 

 or by means of antagonizing drugs, a method of treating 

 and ameliorating disease, and at the same time allowing of 

 an acquisition of a condition of immunity by the patient. 

 It is a well-known fact that certain substances which 

 are in themselves non-poisonous or are only slightly " de- 

 pressant " in their action may so restrain the powers of the 

 tissue cells that organisms that are otherwise incapable of 

 growing in the body are enabled to give rise to septic and 

 putrefactive changes even during the life of the animal. 

 Thus papain and the soluble poison of the Jequirity bean 

 when introduced into the circulation, both so alter the 

 conditions in the body that ordinary putrefactive organisms 

 can make their appearance in enormous numbers in the 

 blood of the animal injected. 



It appears probable that both the antagonistic action and 

 this summative action are due to the bringing into play, or 

 the depressing, of certain specific functions of the proto- 

 plasms of the cells by the products of different micro- 

 organisms. It is not necessary that these functions should 

 always be manifesting themselves ; after being once evoked 

 and exercised they may remain latent for a considerable 

 period and only be again called into action under the regular 

 specific stimulus. It is a case of writing on the looking- 

 glass with ink and with French chalk ; the ink is always in 

 evidence, and we might say that it corresponds to the enzyme 

 or the peptonizing functions exerted by certain cells, animal 

 and vegetable, whilst the French chalk, though always there, 

 is only brought out when the glass is breathed upon. This 

 may be said to exemplify very roughly the specific power 

 that the cell has acquired of resisting the anthrax or other 

 special poison. It only comes into play when the specific 

 poison is present ; it is actually present though in a latent 

 condition the whole time. 



Literature. 



The following works may be referred to : 



Authors already quoted. * Crookshank, Fliigge, Hankin, 

 Sewall. 



BucHNER. — Eine Neue Theorie ii. Erzielung von Immunitat 

 Gegen Infectionskrankheiten. Munich, 1883. 



