88 THE MICROSCOPE. June 
various suture materials as to their sterility, are but a 
few of the possibilities of the pharmacist’s occupation. 
The cost of apparatus for the ordinary work of a bac- 
teriological laboratory is not great, being about $175. 
The following is a list of the most important require- 
ments: Microscope, slides, cover-glasses, platinum wires, 
plates, sterilizer, incubator, gas-regulator, test tubes, stain 
bottles, cornet forceps, enameled iron buckets, flasks, 
retort stand, gas-burners, water-bath, wire baskets, stains, 
gelatin, agar-agar, peptone, and cotton. 
Microscope.—Select the Continental model on account 
of its great stability and ability to stand much use with- 
out getting out of repair. © The stand should be well 
finished, furnished with a graduated draw tube, rack and 
pinion coarse and micrometer-screw fine adjustments. A 
large and heavy bore makes the instrument steady, even 
when the tubeis tilted. A large stage of vuleanized rub- 
ber, fitted firmly to the stage-bed, is better than either 
brass or glass, on account of its durability, since it is not 
attacked by chemicals and does not break readily. The 
sub-stage should be fitted with an adjusting screw of fine 
pitch, so as to admit of the adjustment of the condenser, 
The condenser should be large, fitted with an iris dia- 
phragm and if possible with a ring, attached below, to 
hold a blue glass when working with artificial light, and 
an adjustable mirror with one side plane and the other 
concave, 
The best combination of objectives for this work is 
three-fourths and one-sixth inch dry, and one-twelfth inch 
oil immersion, fitted to a triple nose-piece. The three- 
fourths and one-sixth inch lenses should be free from 
spherical and chromatic aberration. A one-twelfth inch 
oil immersion lens that will give an absolutly flat field 
cannot be purchased for a moderate amount; but one that 
will give a clear picture of stained tubercle bacilli with 
full illumination is sufficiently good for this work. 
