TUBERCULOSIS. 219 



were the exciting causal agents of the disease had been experimentally 

 proved, even before the actual discovery of the bacillus was made, and 

 dogs, which had been in the habit of taking up the sputum of tuberculous 

 persons, had been known to contract the disease, an observation that was 

 fully corroborated by further experiment. Similarly it had been related 

 how barn door fowls in a country district, which for a long time were 

 perfectly healthy > were suddenly attacked by an outbreak of tuberculosis 

 after a phthisical patient had come to live at the farm. The expectorations 

 of this patient were voraciously devoured by the fowls, with the result that 

 tuberculosis of a most virulent nature broke out in a most extraordinary 

 fashion amongst the brood. Feeding experiments were also made to 

 corroborate this accidental experiment ; and more recently similar acci- 

 dental experiments have been recorded both in France and in this country. 



In the case of certain micro-organisms the products of 

 putrefaction exert such a deleterious influence on them that 

 they are destroyed very readily and rapidly. Again, in the 

 case of the cholera bacillus, desiccation at once proves fatal, 

 not only to its growth, but also to its actual virulence and 

 power of infection. In the case of the tubercle bacillus, 

 however, observers, both in France and in Germany, very 

 early pointed out that putrefaction and drying could exert 

 but little influence on the number of the bacilli, whilst dry- 

 ing alone interfered only slightly with their virulence, as it 

 was quite easy to inoculate rabbits with sputum that had 

 been dried at a temperature of 30 C. Later, Galtier found 

 that maceration and putrefaction for a period of five days, 

 and even intermittent freezing and melting, did not interfere 

 with the transmission of the disease by means of the bacillus. 

 Other observers have demonstrated that the bacillus remains 

 virulent after it has been exposed, in sputum, for forty days, and 

 even after 186 days if it is carefully protected from the action 

 of the air. It is, of course, concluded from these experiments 

 that, difficult as it is to cultivate the specific micro-organism 

 of tuberculosis outside the body as a saprophyte, the parasitic 

 form (or its spores) still retains its vitality and power of 

 development for a considerable length of time and under 

 what would appear to be very unfavourable circumstances 

 even when removed from its host. The way was thus 

 being thoroughly prepared for Dr. Georg Cornet's researches 

 on infection in hospitals and rooms where phthisical 

 patients were treated. Dr. Ransome had, early in the con- 

 troversy, demonstrated the presence of tubercle bacilli in the 

 air respired by tuberculous patients ; and Dr. Williams, in 

 1883, suspended glass plates smeared with glycerine for a 



