18 ce) BACTERIA 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, e. 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 1, 
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 0f 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 
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 
Fig. 95.* 
*Fic. 95.—Small cage of wood and glass in which herbaceous plants may be placed for inocu- 
lation by spraying. The inside measurements are 12 by 12 by 30 inches. The large door is a great 
coavenience. Hook-fastenings are better than spring catches. 
