352 AN ADDRESS ON 



refer to his paper ^ you will see that they are very beautiful and very trustworthy. 

 He found that a watery solution of carbolic acid (i in 20) killed the bacilli in 

 thirty seconds ; carbolic acid (i in 100) killed them in a minute ; while corrosive 

 sublimate (i in 1,000), which we had been led to regard as a most potent germicide, 

 required ten minutes for their complete destruction. 



But though the bacilli of tubercle, as grown on glycerine jelly by Yersin, 

 seem really to have had spores, yet those spores were in a less resisting form than 

 they assume in the living body. In sputum, for example, they are much more 

 resisting. Accordingly, I lately asked my colleague. Professor Crookshank, to 

 make some experiments for me with reference to the tubercle bacilli as they 

 exist in phthisical sputum, and he has been good enough to do so. I may refer 

 in detail to the method of procedure. On the 13th of December, 1892, three 

 guinea-pigs were inoculated under the skin of the thigh with a little of the sputum 

 which had been subjected for different periods to the action of a solution of 

 carbolic acid in 20 parts of water. Some of the liquid sputum was introduced 

 into a test-tube ; to this was added the carbolic solution, in volume about five 

 times that of the sputum. This was shaken up freely and then allowed to stand 

 at rest, and after a certain time the supernatant liquid was poured off from the 

 precipitate. Sterilized water was then poured in in abundance, and shaken up 

 with the precipitate to wash out the carbolic acid ; and of the precipitate which 

 again formed a little was introduced by means of a sterilized pipette under the 

 skin of the animal's thigh. If the bacilli were destroyed, no harm would result 

 to the animal ; if, on the other hand, they remained alive, the fact would declare 

 itself in due time by enlargement of the inguinal glands affected by the tubercle. 

 One portion of the sputum was subjected to the action of the carbolic lotion 

 for one minute ; another portion for an hour ; and a third portion for four hours. 

 Three control experiments were performed ; that is to say, three guinea-pigs 

 were inoculated with sputum which had not been acted on by carbolic acid at 

 all, but treated in a similar manner with sterilized water. I saw those guinea- 

 pigs yesterday. The three which were inoculated with the sputum on which 

 carbolic acid had not acted all had enlargement of the inguinal glands of that 

 side, showing that tubercle had developed there. The one that had received 

 sputum acted upon by the i in 20 carbolic solution for one minute had indeed 

 enlargement, but exceedingly trifling compared with that in the other three. 

 The two inoculated with sputum on which the carbolic acid had acted longer, 

 in one case for one hour and in the other for four hours, appeared to have abso- 

 lutely sound groins ; showing that the tubercle bacilh, in this most resisting 

 form in which we can find them, had been perfectly destroyed by the carbolic- 



^ See Annates de I'Institut Pasteur, tome deuxieme, 1888, p. 60. 



