28o 



SPECIFIC MICRO-ORGANISMS 



membrane is produced, so characteristic that the name "mesen- 

 tericus" was applied to this species. It is not pathogenic. 



Bacillus Subtilis. — Bacillus suhtilis, or the hay bacillus, is 

 abundant in the soil and on the surface of plants, and common 

 in surface waters and in the air. It is readily obtained by boiling 

 hay in water and then setting the infusion aside for a few days. 

 The cell is relatively large, about 1.2/* wide by 5/x long, with ends 

 somewhat rounded. Long threads are commonly formed. It 

 is motile with peritrichous flagella. Large oval median spores 



Pig. 1 10. — Bacillus subtilis. Xiooo. 



are formed without distortion of the cell and these are almost as 

 resistant as the spores of the potato bacillus. B. suhtilis grows 

 rapidly on ordinary media in the presence of air, best at about 

 30° C. Gelatin is liquefied and milk is digested. The organism 

 is typically saprophytic, but it has been found growing in the 

 intestine by some investigators, and has been found in a few in- 

 stances in infections of the human eye, cases of panophthalmitis 

 following injury.^ 



1 Silberschmidt, Annates de I'Institut Pasteur, 1903, Vol. XVII, pp. 268-287; 

 Also see Kneass and Sailer, Unh. Penn. Med. Butt., June, 1903, Vol. XVI, pp. 

 131-133- 



