BACILLUS ANTHRACIS 



66 1 



their due weight, no difficulty can be felt in admitting the action of 



Bacteria, &c., in producing decomposition under conditions which 



might at first view be fairly supposed to preclude the possibility of 



their presence. This action is altogether analogous to that of the 



yeast-plant in producing saccharine fermentation ; and the careful 



and exact experiments of Pasteur, repeated 



and verified in a great variety of modes by 



Lister, Tyndall, and others, leave no doubt 



on these 'two points (1) that putrefactive 



fermentation does not take place,* even in 



liquids which are peculiarly disposed to pass 



into it, except in the presence of Bacteria ; 



and (2) that neither these germs nor any 



others arise in such liquids de novo, but that 



they are all conveyed into them by the air 



when not otherwise introduced. It is thus 



also with the parasitic or pathogenic forms 



of Bacteria in setting up disease. Thus 



FIG. 497. Spore-bearing threads of Bacillus 

 anthracis, double-stained withfuchsine and 

 methyleneblue, x 1,200. (Crookshank.) 



FIG. 498. Photograph of a 

 pure-cultivation of Ba- 

 cillusanthracis. ( Crook - 

 shank.) 



1 splenic fever ' is producible by the inoculation of Bacillus anthracis 



(figs. 497 and 498) ; and tetanus or 'lock-jaw ' by inoculation with 



another species of Bacillus, the microbes having been in both cases 



'cultivated,' so as to be free from other contaminating matter. 



Similar observations have been made 



upon tuberculosis (figs. 499 and 500), 



actinomycosis, glanders, so that an 



animal suffering under any of these 



diseases may be a focus of infection 



to others, for precisely the same 



reason that a tub of fermenting beer 



is capable of propagating its fermen- 



tation to fresh wort. A most notable 



instance of such propagation is 



afforded by the spread of the disease FIG. 



termed ' pebrine ' among the silk- 



worms of the south of France, which, 



according to Pasteur, is caused by a 



minute organism named Nosema Bombycis, the mortality caused by 



it being estimated to produce a money loss of from three to four 



millions sterling annually for several years following 1853, when it 



499. Bacilli of tubercle in 

 sputum, x 2,500 (from photo- 

 graphs), stained with carbolised 

 fuchsine. (Crookshank.) 



