2 1 o ELI MI N A TION. 



two very different phenomena the. removal of non- 

 living excrementitious matter from the blood by the 

 agency of epithelial cells, and the passage of living 

 particles through the capillary walls, in which operation 

 it has not been proved that the cells take any part 

 whatever. In the first series of phenomena it is 

 reasonable to conclude that the gland cells are the 

 active agents, and not only take up but change mate- 

 rials which they have absorbed ; in the last it is much 

 more probable that the particles of the poison or virus 

 in the blood move themselves, and pass of their own 

 accord through the vascular walls. So far from being 

 selected or attracted by the epithelium, it is more 

 likely that they bring about conditions which damage 

 it, and in some cases lead to its destruction. 



Indeed, when we examine the seat of actual change 

 in small-pox, so far from finding the cells imagined to 

 be the active agents in eliminating the poison in a con- 

 dition such as we should suppose would be favourable 

 to the operation, we find them terribly deranged, 

 many of them completely destroyed, and the particles 

 which are probably " contagious '' amongst them, 

 dislocating them from their natural positions and 

 damaging them. It would seem that the epithelial 

 cells had been destroyed by the poison, or by the 

 conditions resulting from its presence, rather than 

 that they had selected it from the blood and taken 

 an active part in removing it from the system. 



But if the passage of one kind of living matter 



