OF PUS B10PLA STS. 131 



plasts die, and their death occurs when they are 

 placed in any fluid which is not adapted for their 

 nutrition, the vital movements cease and the cor- 

 puscles invariably assume the spherical form. Not. 

 unfrequently a change occurs in the outer part, and 

 a sort of membrane like a cell wall is produced ; the 

 contents become more granular, and they, assume the 

 appearance usually given in published drawings. 

 After a short time the matter of which they are com- 

 posed undergoes change, and is invaded by bacteria 

 germs, which grow and multiply as represented in 

 Plate XV, fig. 54. These bacteria are not formed 

 directly from the matter of the pus which once lived, 

 but it is quite possible that bacteria germs existed in 

 a living but perfectly quiescent state amongst the 

 oldest particles of the living matter on the surface of 

 the pus corpuscle when it was yet alive. 



