THEIR NATURE. 



vaccinads. " Report on the Cholera Epidemic of 

 1866," p. Ixx. 



The circumstance that vaccine lymph retains its 

 activity if kept in a tube for several weeks, seems 

 conclusive as to the possibility of the particles re- 

 taining their vitality for a considerable time after they 

 have been removed from the place where they grew ; 

 the arguments advanced as proving that the active 

 power resides in the particles and not in the fluid, 

 being admitted. It is not more difficult to explain 

 the fact that such living particles may be dried with- 

 out losing their power, than that an amoeba or rotifer 

 should exhibit the same peculiarity. As this property 

 is observed in connection with many of the lower 

 forms of life, we might almost anticipate that the living 

 matter from the highest organisms, if reduced to a 

 degraded condition, would retain its vitality under 

 circumstances which would cause its death in its nor- 

 mal condition. Yet it must not be supposed that these 

 particles any more than the " dried animalcules " are 

 really dried. Some moisture is retained by the 

 particles within the imperfectly dried mass. Com- 

 plete desiccation will destroy life in both cases. Since 

 it has been shown that the active powers of vaccine 

 lymph reside in the minute particles of living germinal 

 matter, and it has been proved that these may be 

 dried (imperfectly) without loss of power, it is surely 

 not too much to conclude that the materies morbi of 

 other and allied contagious diseases is probably com- 



