604 



Gaseous Edema 



what in size, especially in length, in different culture media. 

 It usually appears thicker and more variable in length in 

 artificial cultures than in the blood of animals. 



The bacillus is not motile and has no flagella. Kndo- 

 spores are formed upon Loffler's blood-serum. 



It was at first thought that the bacillus produced no spores, 

 but Dunham* found that spores were produced upon blood- 

 serum, and especially upon Loffler's blood-serum bouillon 

 mixture. The spores resist desiccation and exposure to the 

 air for ten months. They stain readily in hot solutions of 



fuchsin in anilin 

 water, and are not 

 decolorized by a 

 moderate exposure 

 to the action of 3 per 

 cent, solution of hy- 

 drochloric acid in ab- 

 solute alcohol. They 

 are oval, and are 

 usually situated near 

 the middle of the 

 bacillus, which is 

 distended because of 

 the large size of the 

 spore and bulges at 

 the sides. 



Staining. The or- 

 ganism stains well 

 with the ordinary 



stains, and retains the color well in Gram's method. When 

 stained with methylene-blue a gra"nular or vacuolated ap- 

 pearance is sometimes observed, due to the presence of un- 

 stained dots in the cytoplasm. 



Usually in the body-fluids and often in cultures the bacilli 

 are surrounded by distinct capsules clear, unstained zones. 

 To demonstrate this capsule to the best advantage, Welch 

 and Nuttall devised the following special stain: 



A cover is thinly spread with the bacilli, dried, and fixed 



without overheating. Upon the surface prepared, glacial 



acetic acid is dropped for a few moments, then allowed to 



drain off, and at once replaced by a strong aqueous solution 



* "Bull, of the Johns Hopkins Hospital," April, 1897, p. 68. 



Fig. 178. Bacillus aerogenes capsulatus 

 (from photograph by Prof. Simon Flexner). 



