196 ESCAPE OF DISEASE GERMS 



striking that it could not fail to excite immediate and 

 careful attention. 



In order to make a good artificial injection of 

 healthy capillary vessels, it is necessary, as is well 

 known, to employ some force in pressing down the 

 piston of the syringe, and the injection is seen to 

 spread very slowly from the points where it first 

 appears. It is only after several minutes that the 

 injection becomes complete. In many cases of 

 cholera, however, the injection seemed -to run into the 

 most minute capillaries almost instantly, and under 

 very slight pressure indeed. The capillaries seemed 

 to be filled at once, and extravasation occurred, 

 without any force having been exerted, within half a 

 minute after the injection had been commenced. 

 While injecting the vessels, one was forcibly reminded 

 of what takes place when fine injection is introduced 

 by the aid of very slight pressure into one of the 

 large vessels of a mollusk the force required to 

 inject the smallest vascular ramifications, which in 

 this class are very large, being so slight that the 

 injection will pass freely into the Smaller vessels, 

 although it runs out very fast through the opening 

 made in the larger one, in which the pipe is placed 

 without being tied. 



I think there is little doubt that this increased 

 facility of injection depends upon the extreme 

 stretching to which the coats of the capillaries have 

 been subjected during the course of the disease. The 



