246 OF DISEASE GERMS. 



been very freely supplied with pabulum, and has in con- 

 sequence rapidly increased. The pus-bioplasts may have 

 descended uninterruptedly from the normal bioplasm, and 

 be related to the latter by continuity of descent, PI. V, p. 220. 



It is now held by many pathologists that " the great 

 bulk of pus is everywhere formed, by the migration of 

 colourless corpuscles from the vessels."* On the other hand 

 I consider it proved that the great bulk of pus-corpuscles 

 result from the division and sub-division of the bioplasts of 

 the tissues in which the pus-formation takes place. Although 

 pus-corpusles may result from the growth and multiplication 

 of colourless blood-corpuscles, I regard it as certain that 

 no colourless blood-corpuscle can, by mere change of place, 

 become a pus-corpuscle. The latter result from division 

 and subdivision may be derived by descent from the former ; 

 but a colourless blood-corpuscle is one thing, a pus-corpuscle a 

 different thing altogether. The pus-corpuscle may spring 

 from the colourless blood-corpuscle, but pus-corpuscles 

 Cannot under any circumstances give origin to colourless blood 

 corpuscles. 



Disease Germs. It is by this process of increased mul- 

 tiplication and and reproduction of certain kinds of bioplasm 

 of the organism, under abnormal conditions, that the 

 germs which constitute the material particles concerned in 

 the propagation of contagious diseases result. These living 

 particles (contagium) having somehow acquired during multi- 

 plication new and peculiar properties not possessed by the 

 bioplasm from which they originally sprang, retain these 

 new properties and transmit them to descendants. Such 



* Rindfleisch's "Manual of Pathological Histology," translated for 

 the New Sydenham Society by Dr. Baxter. 



