110 



r.ACTKKIA IN RELATION TO PLANT DISEASES. 



sized book, well bound in leather, so as to stand long and hard usage. The entire 

 quantity of a culture medium is known as a " stock " and receives a special number, 

 which is written, pasted, or stamped on any flask or tube that contains it and 

 which serves to identify it. If a stock is subsequently divided and a portion of it 

 is treated in some different way, c. g., receives more sugar, acid, or alkali, this por- 

 tion receives a new number, or the old number with the addition of a letter of the 

 alphabet. Each stock described in the record book is numbered serially from i, 

 and the book continues in daily use as long as the laboratory, or until it is filled 

 with records and carefully filed away as "Culture Media, Volume I." 



The small pocket ledger, No. 

 492 of A. C. McClurg & Co., Chi- 

 cago, is very convenient for certain 

 kinds of notes, especially those 

 made in the field and those required 

 for the identification of alcoholic 

 specimens and stained slides (fig. 

 112). All records should be in 

 ink, of a sort which does not fade, 

 and in field work a. good fountain 

 pen is invaluable. Pencil records, 

 especially those made with rapid- 

 writing soft pencils, soon become 

 illegible and should not be toler- 

 ated except on paper to be sub- 

 jected to steam heat. 



Large sheets of well-gummed 

 paper should be procured and the 

 labels cut in the laboratory to the 

 size needed. Labels may be cut 

 rapidly in quantity with the appa- 

 ratus used to trim photographic 

 prints for mounts. When exposed 

 to streaming steam such labels 

 come off easily, and it is best not to 

 paste them on the tubes or flasks 



Fig. 95* 



until after the final steam steriliza- 



tion. In moist climates, stock quantities of such gummed labels must be kept in 

 air-tight boxes or between sheets of paraffined paper. Test-tubes in crates are kept 

 separate during steaming by writing the number of the stock on a slip of paper and 

 thrusting this into the crate with the test-tubes. The number should be written with 

 a lead pencil. Faber's pencils for writing on glass are useful in case of flasks and 



: Fn.. 95. Small cage of \vood and glass in which herbaceous plants may l>e placed for inocu- 

 lation by spraying. The inside measurements are 12 by 12 by 30 inches. The large door is a great 

 convenience. 1 lock-fastenings are better than spring catches. 



