48 



You can readily see what an enormous saving of life it 

 would be to the colonies, as well as to Britain, if we could 

 only prevent this disease in its many forms. 



When we consider the prevalence of this disease in man 

 and animals, is it to be wondered at that so many have looked 

 for the cause ? 



Galen, Morgagni, with Budd, were amongst those who 

 from an early time considered it to be an infectious disease. 



Klenche and Villenin were the first to show that sputum 

 or tissue from dead tubercular subjects inoculated into 

 rabbits produced tuberculosis. Cohuheim, an ardent worker 

 on this subject, confirmed these experiments. He inoculated 

 tubercular material into the eyes of rabbits, and was thus able 

 to set up a local tuberculosis which gradually but surely be- 

 came general. 



The result of these experiments suggested that the disease 

 was probably due to a micro-organism, and many looked for 

 it but failed to find it, until Koch by his classical experiments 

 and new methods of staining was able to demonstrate to the 

 Physiological Society at Berlin, in 1882, the bacillus which 

 he argued was the vera causa of tuberculosis. 



Cohnheim now knew, as he had long suspected, that tuber- 

 culosis was a specific disease, and he greeted the new dis- 

 covery with these words : — 



'* I have seldom in all my life felt greater pleasure than at 

 the reception of this news." Koch's arguments were so con- 

 clusive at that meeting that no one ever tried to combat his 

 statement, and he concluded that memorable communication 

 thus : — " We can with good reason say that the tubercle 

 bacillus is not simply one cause of tuberculosis, but its sole 

 cause, and that without tubercle bacilli you would have no 

 tuberculosis." 



Since Koch's discovery the bacillus has been cultivated 

 outside the body, injected into rabbits and guinea pigs, pro- 

 ducing the disease, and there discorerable in the animals so 

 inoculated, conclusive proof that bacillus is the vera causa of 

 tuberculosis, as Koch said. 



Wherever these bacilli are found, no matter what animal 

 they occur in, there the disease tuberculosis is present. They 

 may differ a little in the different animals, but they are prac- 

 tically the same, though the bovine is more virulent than the 

 human. 



They are very minute organisms, about -goVo ^^ laooo ^^ ^^ 

 inch in length, consisting of a delicate sheath with numerous 

 ovoid granules. These are the spores which do not take up 

 the staining matter, hence we get the spore bearing bacillus 

 presenting a beaded appearance. For the most part they are 



