1. BACTBEIOLOGICAL TECHNIQUE. 



Of paramount importance in bacteriological tech- 

 nique is rapid work associated with the best possible 

 results. In preparing, staining, and mounting cover- 

 glass preparations much valuable time is too often wasted, 

 and if this can be reduced to a minimum we are in many 

 ways the gainers. On account of this loss of time the 

 older method of making cover-glass preparations — by plac- 

 ing the material to be examined upon a cover-slip and 

 pressing another slip upon it, staining them in a watch- 

 glass with staining huids made up when desired by adding 

 a few drops of a concentrated alcoholic solution of the 

 stain to be used to water or to aniline water, and mount- 

 ing at once in Canada balsam — has greatly fallen into 

 disuse. 



By far the larger portion of cover-glass preparations 

 made, are prepared purely and simply for the purpose of 

 diagnosis; it is therefore ordinarily a useless waste of 

 cover-slips to make two preparations from the same ma- 

 terial, especially as such preparations are frequently much 

 too thick to be considered beautiful or even worthy of per- 

 manent mounting. Similarly it is evident that it is need- 

 less to mount at once in Canada balsam, for cover-glass 

 preparations are invariably thrown away after a short 

 microscopical examination, not because the preparations 

 are poor, but rather because they were made only for 

 diagnosis, which having been accomplished they are only 

 in the rarest cases of further use. Moreover, after mount- 

 ing in balsam one should properly wait until the balsam is 

 dry before examining in oU, or run the risk of making an 

 unsightly preparation; here again much time is lost 

 Furthermore, the staining may be greatly accelerated. It 

 is seldom necessary to stain in the watch-glass or to make 

 up one's staining fluids as required; the fluids for ordinary 

 staining should always be ready for use. The staining is 

 best and simplest performed upon the cover-glass, after 

 which the preparation may be mounted and at once ex- 

 amined in water. It is then a simple matter, if desired. 



