CARRIAGE OF DISEASE 163 



smears were taken from the thoracic duct which indi- 

 cated tubercle bacilli, thus showing how easily these 

 bacilli can enter the general circulation. 



Dr. Frederick T. Lord (1904), after a series of long 

 and careful laboratory investigations, reached the fol- 

 lowing conclusions: 



"i. Flies may ingest tubercular sputum and excrete 

 tubercle bacilli, the virulence of which may last for at 

 least fifteen days. 



"2. The danger of human infection from tubercular 

 fly-specks is by the ingestion of the specks on food. 

 Spontaneous liberation of tubercle bacilli from fly- 

 specks is imlikely. If mechanically disturbed, infec- 

 tion of the surrounding air may occur. 



"As a corollary to these conclusions, it is suggested 

 that — 



"3. Tubercular material (sputum, pus from dis- 

 charging sinuses, fecal matter from patients with intes- 

 tinal tuberculosis, etc.) should be carefully protected 

 from flies, lest they act as disseminators of the tubercle 

 bacilli. 



"4. During the fly season greater attention should 

 be paid to the screening of rooms and hospital wards 

 containing patients with tuberculosis and laboratories 

 where tubercular material is examined. 



''5. As these precautions would not eliminate fly in- 

 fection by patients at large, foodstuffs should be pro- 

 tected from flies which may already have ingester tu- 

 bercular material." 



According to Nuttall and Jepson, the first investi- 



