52 THE TONER LECTURES. 



ries in the inflamed mesentery of a frog will meet, at not very 

 infrequent points, with just such appearances of the interior of 

 the vessel as the detachment of an epithelial cell will go far to 

 explain the significance of. I confess that I am inclined to 

 believe that this appearance would occur much more frequently 

 but that soon a white corpuscle possessing unusual viscosity, 

 fastening itself there, spreads out and fills the void. It will be 

 remembered that, a propos of the apex of the forty -eight hour 

 blood-clot of a ligated artery, a number of epithelioid cells pres- 

 ent in the clot were both described and figured. 



As a possible explanation of their presence, we may suppose 

 that they may have been detached from the irritated intima 

 at or above the level of their location in the clot. 



Once admitting, in inflammations affecting the inner lining 

 of bloodvessels, this detachment of swollen and irritated epithe- 

 lium, it may be claimed as a necessary consequence that those 

 cells must appear in appreciably increased numbers in the 

 blood. Now precisely this is found to be true respecting the 

 blood in the inflamed stump of a ligated artery ; on the other 

 hand, it has not yet been observed of the blood in more general 

 inflammations. It may be affirmed respecting the latter cases 

 that because the expected increase is not apparent the theory 

 has at once been placed hors de combat. 



But does it necessarily follow that herein is an insupei-able 

 objection ? These swollen granular epithelial cells which are 

 displaced from their position on the internal lining membrane 

 of a vessel are in a state of irritation. What should happen 

 to their shape after being set free in the blood current ? 

 Under this condition undoubtedly their tendency would be to 

 assume a spherical outline, and, if they should remain sus- 

 pended sufficiently long in the flowing blood, it is probable that 

 every trace of their original form would be obliterated. 



Concerning the changes which an endothelial cell may pass 

 through under somewhat similar conditions, is an observation 



