CHAPTER III. 

 BACILLUS AEROGENES CAPSULATUS. 



THIS very interesting micro-organism was first de- 

 scribed by Welch, and subsequently carefully studied by 

 Welch and Nuttall, 1 and Welch and Flexner. 2 It was 

 first secured from the body of a man dying suddenly of 

 aneurysm with a peculiar condition of gaseous emphy- 

 sema of the subcutaneous tissue and internal organs, and 

 a copious formation of gas in the veins and arteries. 

 The blood was thin and watery, of a lac-color, and 

 everywhere contained large and small gas-bubbles. The 

 blood-alteration was associated with a change in its 

 coloring-matter, which dissolved out of the corpuscles 

 and stained the tissues a deep red. The blood was found 

 to contain many bacilli, which were also obtained from 

 the various organs, especially in the neighborhood of the 

 gas-bubbles. The bacilli were in nearly pure culture. 



The bacillus is a large organism, measuring 3-5 // in 

 length, about the thickness of the anthrax bacillus, with 

 ends slightly rounded, or, when joined, square (Fig. 132). 

 It occurs chiefly in pairs and in irregular masses, but not 

 in chains, in this particular differing very markedly from 

 the . anthrax bacillus. In culture-media the bacillus is 

 usually straight, with slightly rounded ends. In old 

 cultures the rods may be slightly bent, and involution- 

 forms occur. When several bacilli are joined together 

 the opposed ends are square-cut. The bacillus varies 

 somewhat in size, especially in length, in different cul- 

 ture-media. It usually appears thicker and more vari- 



1 Bull, of the Johns Hopkins Hospital, July and Aug., 1892, vol. viii., 

 No. 24. 



2 Jour, of Exper. Med., vol. i., No. I, Jan., 1896. 



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