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 

 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 the lamp. 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. 



1g. 102. Small 

 pipette with 

 twisted neck, 

 corked with cot- 

 ton wool and 

 sterilized. 



