608 RErORT OF THE COMMISSIONER OF AGRICULTURE. 



Five tubes treated as before, using a .002 per cent, solution. All tubes clear ex:- 

 cepting the one inoculated after G minutes" exposure. 



Five tubes inoculated at the end of 5, 10, 15, 20, 25, and 30 minutes after exposure 

 to a .0001 per cent. (1 : 100000;. Tubes inoculated after 5 and 10 minutes turbid next 

 day. On the second day all but the one inoculated after 30 minutes turbid and con- 

 taining pure cultures of the bacterium. 



The limit of disinfection for this period of time must therefore lie between 1 : 50000 

 and 1: 100000; hence 5 tubes were inoculated as above, using a solution of 1 : 75000, 

 at the end of 7, 10, 15, 20, 25, and 30 minutes. All tubes remained clear. 



Carbolic acid destroys the bacterium in solutions containing from 

 1 to li per cent, of the acid by weight. 



Five tubes inoculated after treating the bacterium from a liquid culture with a 1 

 per cent, solution for 5, 10, 15, 20, and 25 minutes. All turbid on the following day. 

 The two last tubes were also examined on gelatine plates and the cultures foimd 

 pure. 



With a 2 per cent, solution, five tubes inoculated after 10, 15, 20, 25, and 30 min- 

 utes remained sterile. The same result with a li per cent, solution. With a 1^ per 

 cent., tubes inoculated at the end of 7, 10, 15, 20, 25, and 30 minutes remained clear, 

 excepting the first, which contained bacillus subtilis. 



Passing to a i per cent, solution, tubes inoculated at the same intervals became 

 turbid with the bacterium sown. With a f per cent, solution the result was the 

 same. 



Passing back to a 1 per cent, solution, tubes inoculated at the same intervals re- 

 mained sterile. 



There seems to be an incompatibility between the first and last series. If we ex- 

 amine the others, however, we must conclude that the limit of disinfection lies 

 between 1 and li per cent. 



Iodine water was prepared by shaking up some iodine in distilled 

 water, which assumed an amber tint. This solution destroyed the 

 bacterium in 15 minutes, as the following experiment shows: 



Six tubes were inoculated with, bacterium after they had been exposed to the ac- 

 tion of the iodine water for 7, 10, 15, 20, 26, ajid 31 minutes. On the following day 

 the first tube became turbid; on the second the 10-minute tube was turbid and found 

 to be a pure culture of the bacterium sown. The other tubes remained sterile. One 

 of them, inoculated later, showed its capacity for sustaining growth by becoming 

 promptly turbid. 



Permanganate of potash. — A series of experiments with this sub- 

 stance, conducted in the manner described above, showed that the 

 bacterium is killed by 15 minutes' exposure to .03 per cent, solution 

 tion (1:5000). 



' In order to obtain this result a 5 per cent, solution was tried first. Tubes inocu- 

 lated after an exposure of the virus for 7, 10, 15, 20, 25, and 31 minutes remained 

 permanently clear. One of these tubes, subsequently inoculated with the unaffected 

 virus, was turbid next day. Two and a half per cent., 1 per cent., i per cent., i per 

 cent. , i^j per cent. , and ia per cent, solutions were tried in the same way. The six 

 tubes used for each solution remained sterile. Finally a t;^ per cent. (1 : 5000) was 

 used. Tubes were inoculated after an exposure of the virus for 2, 4, 6, 10, 15, 20, 25, 

 and 30 minutes. On the following day the four first tubes were turbid; the fifth 

 and seventh remained sterile; the sixth and eighth contained a fine bacillus. These 

 two tubes, as was found later, belonged to a lot which, through some carelessness, 

 had not been properly sterilized, and the majority became turbid before use. 



Mercuric iodide was found to destroy the bacterium in solution of 

 1 : 1000000 in 10 minutes. 



Tavo grams of potassium iodide and 1 gram of mercuric iodide .were dissolved in 

 100" of distilled water, making a 1 per cent, solution of the disinfectant in a 2 per 

 cent, solution of potassium iodide. 



This solution, diluted with sterile distilled water so as to make .1 per cent., killed 

 the bacterium of hog-cholera taken from liquid cultures in less than 5 minutes; 

 .01 per cent. (1 : 10000), .002 per cent. (2 : 100000), .001 per cent. (1 : 100000), and .0005 

 per cent. (5 : 1000000) destroyed the germ within 2 minutes. 



When the solution was diluted so as to make .0002 per cent, (2 : 1000000) and .0001 



