BACTERIA 



Cornet's forceps, two small bottles of stain, say 

 Carbol-Fuchsine and Methylene Blue and a larger 

 bottle of J per cent. Acetic acid; these may be 

 obtained from the firm who supplied our micro- 

 scope and, for the beginner at any rate, it is cheaper 

 to buy the solutions ready made, than to attempt 

 to make them up at home. Slides and cover slips, 

 we require, of course, and they must be absolutely 

 grease proof; it may be necessary to boil them in 

 a strong solution of caustic soda to effect this 

 result. A small bottle of Canada Balsam completes 

 our requirements. 



Should we wish to examine a drop of milk for 

 bacteria, we proceed in this manner. With the aid 

 of the Cornet's forceps pick up two cover slips, place 

 a drop of milk on one and cover with the other. 

 With thumb and finger bring the glasses into close 

 contact, so that the milk forms a thin film. Slide 

 one glass from the other and set aside, milk side 

 upwards, till dry. Next take each cover slip, 

 separately, in the forceps and pass rapidly two or 

 three times through the flame of a spirit lamp, this 

 fixes the bacteria, if any be present, to the glass. 

 Now having poured a little of the stain, say methy- 

 lene blue, into a shallow vessel, a saucer will do, 

 we place our cover slips therein for two minutes or 

 so. Then, remove them with the forceps, wash in 

 water till no more stain comes away and set aside 

 to dry. When dry, take a clean slide, place a small 

 drop of Canada Balsam at its centre and gently 

 lower the cover slip thereon, stained side down- 



163 



