CHEMICAL STERILIZATION, ETC. 69 



where the solution used is not freshly prepared. With 

 the introduction of such substances into the sublimate 

 solution the mercury is quickly precipitated by the 

 albumin, and its disinfecting properties may be entirely 

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

 than water containing a precipitate of albumin and 

 mercury, in so far as its value as a disinfectant is con- 

 cerned. 



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. 



Where it is desirable to use chemical disinfectants 

 in the laboratory much more satisfactory results can 

 usually be obtained through the employment of carbolic 

 acid in solution. A three or four per cent, solution of 

 commercial carbolic acid in water requires a somewhat 

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

 open to fewer objections than are solutions of the inor- 

 ganic salts, though here, too, we find a somewhat anal- 

 ogous 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. 



In the laboratory heat is the surest agent to employ. 

 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. 



Intestinal evacuations may best be disinfected with 



