70 BACTERIOLOGY FOR NURSES 



not for its resistant spores. Its presence there is a greater menace 

 to animals than to man. 



Malignant Edema. Wound infections with the bacillus of 

 malignant edema occur which give rise to extensive hemorrhagic 

 edema. The bacillus is an anaerobe and occurs in the upper 

 layer of the soil. 



Welch's Gas Bacillus or B. aerogenes capsulatus. This or- 

 ganism occurs in the intestines of man and animals and in the soil. 

 When introduced into wounds it may produce suppuration and a 

 great amount of gas. In the majority of cases it leads to no harm, 

 yet in a small percentage it causes one of the most rapidly fatal 

 infections known. 



Typhoid Bacillus. Typhoid bacilli may find their way into the 

 soil with human excreta. Multiplication, however, rarely takes 

 place there. As a rule they do not live more than a month unless 

 the ground is frozen, in which case their life may be prolonged 

 to several months. The chief danger so far as typhoid bacilli 

 are concerned is the washing by heavy rains of human excreta 

 that has been deposited on the ground into a stream used for 

 drinking purposes, or drainage through the soil into a near-by 

 well. 



Cholera Spirillum. Cholera spirilla too may be deposited 

 upon the ground in human feces; they live only a very short 

 time there and are not likely to regain entrance into the human 

 body except by means of drinking water. 



BACTERIA IN THE INDUSTRIES 



The ability of bacteria to produce decomposition is the basis 

 of several industries. Certain of these depend upon the result 

 of bacterial fermentation, others exist to prevent it. Many of 

 them were in operation long before their intimate relation to bac- 

 terial activity was known. In some cases the original methods 

 are still employed, though modified somewhat by the use of pure 

 cultures or an increased knowledge of antiseptics and germicides. 



Preservation of Food. The ceaseless energy of bacteria and 



