Morphology 343 



with Bacillus pefringens of Veillon and Zuber,* and Besson describes 

 it under this name. Pending final decision upon the identity of these 

 organisms, it is here called by the name originally given it by Welch 

 who first secured it from the body of a man dying suddenly of 

 aortic aneurysm with a peculiar gaseous emphysema of the sub- 

 cutaneous tissues and internal organs, and a copious formation of 

 gas in the blood-vessels. The blood was thin and watery, of a lac 

 color, and contained many large and small gas bubbles, and many 

 bacilli, which were also obtained from it and the various organs, 

 especially in the neighborhood of the gas bubbles, in nearly pure 

 culture. The coloring-matter of the blood was dissolved out of the 

 corpuscles and stained the tissues a deep red. 



Distribution. — ^It is believed that the natural habitat of the ba- 

 cillus is the soil, but there is reason to think that it commonly occurs 

 in the intestine, and may occasionally be found upon the skin. 



Fig. 116. — Bacillus aerogenes capsulatus (from photograph by 

 Prof. Simon Flexner). 



Morphology. — The bacillus is a large organism, measuring 3-5 m 

 in length, about the thickness of the anthrax bacillus, with ends 

 slightly rounded, or, when joined, square. It occurs chiefly in pairs 

 and in irregular groups, but may also occur in chains. In culture 

 media it is usually straight, with slightly rounded ends. In old 

 cultures the rods may be slightly bent, and involution forms occur. 

 The bacillus varies somewhat 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. In the blood and 

 tissues of animals and in albuminous media it forms rather broad 

 capsules. 



Dunhamf found that spores were produced upon blood-serum, and 



* Archiv de med. exper. et d'anat. path., 1898, x, 517. 



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



