260 MICROBES, FERMENTS, AND MOULDS. 
dehydrate and partially decolourize preparations: 
Canada balsam is used to mount them; and finally 
distilled water, absolutely free from microbes, which 
may be easily obtained by means of the Chamberland 
filter already described, is used for washing instru- 
ments, etc. 
Mode of collecting the Liquids to be examined.—In 
od 
Fig. 102. — Small 
pipette with 
twisted neck, 
corked with cot- 
ton wool and 
sterilized. 
order to collect the liquids to be obtained 
in the wards of a hospital or elsewhere 
(blood, urine, sputum, stagnant or sewer 
water, etc.), pipettes, which may be either 
straight or with twisted necks, are used, 
ending in a capillary point closed by 
heat,'and in its upper part by a stopper 
of fine, sterilized cotton wool. The 
pipette is heated at a blowpipe flame, 
in order to destroy the germs. When it 
is to be used, the point is broken off, 
and it is plunged into the liquid (dis- 
charge from a freshly opened abscess, 
blister of erysipelas, etc.), and an aspira- 
tion is made through the other end. The 
liquid is unable to rise above the level 
of the twisted neck; and this is important, 
especially when the aspiration is made 
by the mouth. The point is then resealed 
at thelamp. The shape of these pipettes 
may be varied according to the require- 
ments, so long as the same precautions are always 
taken to avoid mistakes. 
