ip75 TUBERCULOSIS 



Lord (1904) made a number of careful investigations. 



In one experiment lie placed about 30 flies in an inverted jar together with a small 

 dish containing tubercular sputum showing about 10 tubercle bacilli in the field, and 

 around it some clean cover-glasses. "Examination of many specks on the cover- 

 glasses showed that the number of bacilli in each microscopic field had increased from 

 about 10 in the original sputum to 150 in the specks. Each speck contained 3000 to 

 5000 bacilli. Aiwut 2000 specks had been deposited by 30 flies within three days, 

 thus from 6,000,000 to 10,000,000 tubercle bacilli had been transferred from the 

 sputum to the inner side of the cage during this period." By inoculation experiments 

 he proved that the bacilli in these frecal deposits, when protected from the direct 

 sunlight, were virulent for guinea-pigs up to the 15th day, but not on the ^Sth and 

 55th days. He also made sections of flies which had fed on tubercular sputum, and 

 found the bacilli in their intestinal contents. " No invasion of other parts of the body 

 could be determined." 



Hay ward (1904) also made a series of interesting ob- 

 servations, 



' ' Flies caught feeding on the bottles containing tuberculous sputum that came to 

 the laboratory for examination " were placed in a cage, and deposited fseces on clean 

 cover-slips. Ten out of sixteen cover-slips examined showed tubercle bacilli. Control 

 examinations of faeces of flies had shown that no acid-fast bacilli were present in them. 

 Other flies were fed on tuberculous sputum placed in watch-glasses and covered with a 

 line wire screen. "On this screen the fly could walk without getting its feet or 

 wings in sputum and could feed through the meshes." Tubercle bacilli were found irt 

 the feces and in the intestines of these flies, and guinea-pigs injected with emulsions 

 of their faeces died of tuberculosis. He further states "culture plates made of the 

 fisces on glycerine agar and incubated two weeks, showed a growth of tubercle 

 bacilli." 



Hayward seems to have been the first to notice that "flies 

 apparently suffer from diarrhoea after feeding on sputum." 



Cobb (1905) writing on this subject says : — " I have demon- 

 strated that the fly carries the bacillus," but does not quote his 

 experiments, 



Buchanan (1907) made the following investigations: 



" To test the power of flies in relation to expectoration a specimen of tuberculous 

 sputum rich in Bacillus tuberculosis was spread in a thin film in the bottom half of a 

 Petri capsule. A house-fly was introduced into the capsule, and caused to walk over 

 the film for a few minutes. It was then transferred to another Petri capsule containing 

 a layer of agar. On washing the surface of the agar with a cubic centimetre oi 

 bouillon and inoculating a guinea-pig intraperitoneally therewith, tuljerculosis was 

 induced which killed the guinea-pig in 36 days." 



Graham-Smith (1910, p. 27) carried out elaborate experi- 

 ments with cultures of B tuberculosis and with sputum containing 

 this organism. 



