512 Influence of certain Reagents on Bacillus tuberculosis. 



with this agent, and resulted in demonstrating that the nnmber of 

 bacilli decreases rapidly under its influence, and that the bacilli in the 

 sputum after being mixed with quinine could not be cultivated even 

 in the beef solution before mentioned, thus showing that this drug 

 not only arrests the growth of the bacillus, but destroys its power of 

 multiplication. All the solutions of quinine appear to possess this 

 property, but the stronger ones to the greatest extent. 



Arsenious Acid. — This exercised no destructive influence on the 

 bacilli, which increased sixfold in both strong and weak solutions. 

 The rods were generally short, with occasional long ones, and but few 

 spores, and the groups were scanty in number. 



Boracic Acid. — The bacilli increased more abundantly in solutions 

 of this than in arsenic, and displayed many groups of 2, 5, 7, and 10. 

 Rods in couples, arranged at an angle of 45°, were common. They 

 were of fair length and many contained spores. Multiplication by 

 division was proceeding. 



Iodine. — This drug reduced the numbers very considerably, and in 

 many fields of the microscope it was difficult to find any bacilli, in 

 others a few were present, but these showed no spores or indications 

 of growth. 



Perchloride of Mercury caused no diminution, but rather a marked 

 increase in the number of the bacilli. They were longer and with 

 more spores than in the standard solution. 



The tubercle bacillus is characterised by great durability of 

 structure, as evidenced by its not being destroyed by the strong acids 

 used in the various processes for its detection, and by its little 

 tendency to decomposition. It does not multiply in distilled water, 

 but does so largely in beef solutions. Arsenic, boracic acid, and per- 

 chloride of mercury do not interfere with its development, but rather 

 promote it. Quinine and iodine (especially the former) appear to 

 entirely arrest its growth and destroy its power of multiplication. 



