172 BACTERIOLOGICAL DIAGNOSIS. 
thoroughly cleaned ; it may be scrubbed with soap and 
a nail brush, using plenty of hot water. The films 
need not be very thin and even. 
The method of staining will depend upon the organ- 
ism which is likely to be found, and more especially 
whether it stains by Gram’s method. This is so impor- 
tant in this connection that a repetition of a previous 
table will not be out of place. 
Gram’s MeETHop. 
Stained. Unstained. 
Streptococci. Typhoid bacilli. 
Staphylococci. Bacillus of glanders. 
Bacillus of anthrax. Bacillus of influenza. 
Bacillus of tubercle. Bacillus of plague. 
Pneumococcus. Bacillus coli. 
Spirillum of relapsing fever. 
Gonococcus. 
If the organism which is present appears in the first 
list the staining process is simply that which we have 
described previously, and the organism will be stained 
dark blue or violet and the other structures will be 
unstained. 
If the bacteria which are present in the films do not 
stain by Gram’s method the matter is more difficult, for 
any stain which colours them will colour the nuclei of 
the leucocytes also. Jenner’s stain may be used, or 
the film may be stained by eosin and methylene blue 
separately. The organisms will then be stained blue. 
Carbol-thionin is even more suitable, as the colour 
which it imparts to the nuclei of the leucocytes is not 
deep and the red corpuscles are merely tinged. This is 
