An excellent fluid for cleaning slides and coTer- 

 glasses, in fact, for cleaning any glassware, is the follow- 

 ing: 



Water 50 parts 



Alcohol 45 parts 



Ammonia 5 parts 



The writer has tried many methods and many fluids 

 for cleaning up old balsam or other preparations, but he 

 has never found anything so satisfactory as the above. 

 A small covered vessel of this fluid may be kept upon the 

 desk, and any preparations that are further useless may 

 be placed therein and allowed to remain until one has a 

 leisure hour for cleaning them. In a few days, the balsam 

 or the dried material upon the glass or the slide becomes 

 softened or loosened and is easily rubbed off with a cloth; 

 thus covers and slides may be used over and over again. 



Another place wherein a little time may be saved is 

 in making plate-cultures. Petri dishes have largely dis- 

 placed the old-fashioned plates, but the latter may still 

 often be employed to advantage, and much time may be 

 gained, by having a sufiBciently large cooling-plate, upon 

 which, under three small bell-jars, the small plates can be 

 cooled. All three plates (for although as a rule only two 

 plates are preserved, it is often wise to keep all three) 

 are then flowed in rapid succession, and while the gela- 

 tin is cooling the moist chamber may be prepared. More- 

 over, it is a useless waste of time to label each tube in 

 writing as the dilutions are being made; it is sufficient 

 simply to mark each tube by twisting a small portion of 

 the cotton-plug into one or two small "ears." 



Again much time may be saved by not labelling every 

 tube-culture. It is customary to "carry over" each differ- 

 ent culture in the laboratory supply every month. In do- 

 ing this one generally makes several new cultures, for 

 instance: Two or more cultures in gelatin; two or more 

 in or upon agar; on agar and glycerine; on potatoes, etc. 

 By this procedure one is apt not only to notice the vari- 

 ations of growth in the organism, but runs no risk of also 

 losing one or more altogether by the accidental entrance 

 of some mould or other foreign plant. These new cultures, 

 then, having been made are best placed in a tumbler hav- 

 ing a little cotton in the bottom to prevent breakage, plac- 

 ing only cultures of the same organism in one tumbler. 

 It is now absolutely useless to label each tube; writinsr 

 upon a piece of filter-paper and placing this writing out- 

 ward within the tumbler is all sufficient. 



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