372 POISONS, CONTAGIONS, MIASMS. 



indispensable for the support of the vital functions 

 of certain principal organs, death is the consequence 

 of their transformation. But if the absence of the 

 one substance which was a constituent of the blood 

 do not cause an immediate cessation of the func- 

 tions of the most important organs, if they continue 

 in their action, although in an abnormal condition, 

 convalescence ensues. In this case the products 

 of the transformations still existing in the blood are 

 used for assimilation, and at this period secretions 

 of a peculiar nature are produced. 



When the constituent removed from the blood 

 is a product of an unnatural manner of living, or 

 when its formation takes place only at a certain 

 age, the susceptibility of contagion ceases upon its 

 disappearance. 



The effects of vaccine matter indicate that an 

 accidental constituent of the blood is destroyed by 

 a peculiar process of decomposition, which does 

 not affect the other constituents of the circulating 

 fluid. 



If the manner in which the precipitated yeast of 

 Bavarian beer acts (page 266) be called to mind, 

 the modus operandi of vaccine lymph can scarcely 

 be matter of doubt. 



Both the kind of yeast here referred to and the 

 ordinary ferment are formed from gluten, just as 

 the vaccine virus and the matter of small-pox are 

 produced from the blood. Ordinary yeast and the 

 virus of human small-pox, however, effect a violent 



