CHEMICAL STERILIZATION AND DISINFECTION. 89 



in which the substance to be disinfected is of a proteid 

 nature and where the solution used is not freshly pre- 

 pared and frequently replenished. On the introduction 

 of such substances into the sublimate solution the mer- 

 cury is quickly precipitated by the albumin, and its dis- 

 infecting properties may be in large part or entirely 

 destroyed ; we may in a very short time have little else 

 than water containing an inactive precipitate of albumin 

 and mercury, in so far as its value as a disinfectant is 

 concerned. 



Though the other inorganic salts have not been so 

 thoroughly studied in this connection, it is nevertheless 

 probable that the same precautions should be taken in 

 their employment as we now know to be necessary in 

 the use of the salts of mercury. 



PRACTICAL DISINFECTION. Where it is desirable 

 to use chemical disinfectants in the laboratory, much 

 more satisfactory results can usually be obtained from 

 the employment of carbolic acid in solution. A 3 or 4 

 per cent, solution of commercial carbolic acid in water 

 requires longer for disinfection ; but it is, at the same 

 time, open to fewer objections than are solutions of the 

 inorganic salts ; though here, too, we find a somewhat 

 analogous reaction between the carbolic acid and proteid 

 matters. Under ordinary circumstances its action is 

 complete in from twenty minutes to one-half hour. It 

 is not reliable for the disinfection of resistant spores ; 

 such, for instance, as those of bacillus anthracis. 



All tissues containing infectious organisms should be 

 burned, and all cloths, test-tubes, flasks, and dishes 

 should be boiled in 2 per cent, soda (ordinary washing- 

 soda) solution for fifteen to twenty minutes, or placed 

 in the steam sterilizer for half an hour. 



