STERILISATION OF APPARATUS. Q 



An efficient steriliser may be made out of a cubical 

 biscuit box, but it will not stand much usage unless the 

 joints are brazed instead of being soldered : this can be 

 done by any tinsmith. It is much better to have the 

 the bottom of the box replaced by a sheet of copper, 

 and a steriliser made in this way will answer every 

 purpose and be fairly durable. A circular hole is cut 

 through the centre of the lid and fitted with a cork 

 bored so as to admit the thermometer. A false bottom 

 or a shelf an inch or so from the bottom will keep the 

 articles which are being sterilised from the heated 

 surface ; the false bottom may be made from a sheet of 

 tin two inches longer in one of the sides than the 

 bottom of the box. The extremities of the longer sides 

 are to be turned down for a length of an inch, and 

 several holes cut in the plate. 



Lastly, the kitchen oven may be pressed into service 

 if no other steriliser is at hand in an emergency. The 

 apparatus to be sterilised is to be placed on a layer of 

 cotton-wool on one of the shelves, and the temperature 

 is observed by means of the thermometer, which should 

 be thrust through the little window which permits of 

 the regulation of the temperature. Or the heat may be 

 continued until the cotton-wool is singed over the whole 

 of the exposed surface. This method is very convenient 

 for practitioners sending materials to a laboratory for 

 bacteriological examination. 



A gas oven is even more convenient, as the tempera- 

 ture can be regulated to a nicety. 



All glass apparatus must be thoroughly cleansed and 

 dried before sterilisation. The remaining steps differ 

 somewhat in the different cases. 



Flasks are plugged lightly with cotton-wool before 

 being placed in the steriliser. Bottles may be sterilised 



