FATE OF TUBERCLE BACILLI OUTSIDE THE 

 ANIMAL BODY 



BY CHAS. F. BRISCOE, INSTRUCTOR IN BOTANY 1 



INTRODUCTION 



The fact that one-tenth of all deaths in the human family are 

 due to tuberculosis, and that millions of dollars worth of farm 

 animals are lost annually from its ravages, makes any knowledge 

 concerning the fate of tubercle bacilli outside of the animal body 

 of great value. 



These questions have often come from stock owners : How 

 long is it necessary to keep healthy stock from a field where tuber- 

 culous cattle have been previously allowed to run? How long do 

 tubercle bacilli live in manure, in a watering trough, and in a dead 

 tuberculous animal ? And again, some authors have questioned the 

 reports in the literature that tubercle bacilli remain alive and viru- 

 lent for periods of a year and more outside of the animal body, 

 They have suspected that in such cases the tubercles, found in the 

 test animals after inoculation with such tuberculous material, kept 

 for these long periods, had been produced by dead tubercle bacilli. 

 It has been, in part, the purpose of this bulletin to answer these 

 questions. 



The first section is devoted to brief notes on the biology of the 

 tubercle bacillus; then a tabular review of the literature is given 

 \vith brief discussions; and lastly an account of the experimental 

 work, followed by a general discussion. The experiments deal 

 with pure cultures of tubercle bacilli, and with those of some other 

 bacteria for purposes of comparison as to their duration of life in 

 sunlight and under desiccation; and with the time limit of life of 

 tubercle bacilli in cow manure, garden soil, water, butter, and dead 

 tuberculous animals. 



BIOLOGY OF THE TUBERCLE BACILLUS 



MORPHOI OGY ^ lie tll1:)ercle bacillus varies in form according to 



type, method of growth, and age of the individual 



culture. It is a slightly curved, rod-shaped organism measuring 



from 0.3 to 0.5 microns in diameter and from 2 to 5 microns "in 



I Now Professor of Bacteriology in the Mississippi Agricultural Experiment Station, 

 Agricultural College, Mississippi. 



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