GERMS INTO VESSELS. 



distended with blood, their walls are rendered still 

 thinner, and they come still nearer to the surface. 

 The capillaries of parts of the mucous membrane of 

 the nose, mouth, fauces, and conjunctiva, even in a 

 state of perfect health, are covered with a very thin 

 layer of protective epithelium, while those of the air- 

 cells of the lung are practically bare. Through these, 

 minute germs might readily pass. In many morbid 

 states, the epithelial covering of the mucous mem- 

 branes above enumerated, is very soft, and sometimes 

 it is reduced to a thin layer of moist, pulpy mucous 

 material in which any foreign particles would very 

 readily become embedded. In such a material, con- 

 tagious disease-germs would find a nidus suitable for 

 their reception, and at the same time probably also 

 soluble materials adapted for their nutrition. Having 

 fallen into this, they would grow and multiply, 

 and minute offsets from them might soon make their 

 way to the external surface of the thin capillary 

 walls. 



When the capillaries are much stretched, as is 

 always the case when they are fully distended with 

 blood, the minute particles of living germinal matter 

 or bioplasm of the blood, as well as diverticula from 

 the white blood-corpuscles, readily make their way 

 out of the capillaries through the walls with the 

 blood serum, and grow and multiply in their new 

 position. Even red blood-corpuscles, as is well 

 known, often pass through the vascular walls under 



