BACTERIUM WELCHI1. 535 



animal bodies. It is a non-motile, spore-forming 

 organism, and is strictly anaerobic in character. It 

 stains with the ordinary aniline dyes and by the Gram 

 method. 



Under anaerobic conditions the organism grows on 

 the usual culture media at room temperature, and forms 

 large quantities of gas in media containing carbohy- 

 drates. Gelatin is not liquefied. In agar-agar the col- 

 onies are usually from 1 to 2 millimetres in diameter, 

 but may be as large as 1 centimetre in diameter. They 

 have a grayish-white color, are flat, round or irregular 

 masses, with small hair-like projections from the mar- 

 gin. In bouillon there is a diffuse clouding and marked 

 white sediment. Milk is quickly coagulated. On 

 potato there is a grayish-white layer. 



The organism grows more rapidly at 30 to 37 C. 

 than at 18 to 20 C. Cultures on agar-agar and bouil- 

 lon have a slight odor resembling old lime. Bouillon 

 cultures are killed after ten minutes at 58 C. 



Bacterium Welchii was first described by Welch in 

 1891, and subsequently by Welch and Nuttall l in the 

 blood and internal organs of a patient with thoracic 

 aneurism opening externally. Autopsy was made eight 

 hours after death and the vessels were found to contain 

 large numbers of gas bubbles. 



Injections of considerable quantities of cultures into 

 the circulation of rabbits did not kill the animals, but 

 if the animals were killed after being inoculated and 

 were then allowed to lie at room temperature for twenty- 

 four hours the organs and tissues were filled with gas 

 bubbles. 



1 Welch and Nuttall: Bulletin Johns Hopkins Hospital, No. 24, 1892. 



