6 BACTERIOLOGICAL DIAGNOSIS. 
gain in magnification brought about by the eye-piece is 
attended by a loss of definition. The same applies to 
the increased magnification obtained by pulling out- the 
draw-tube. : 
“The total cost of a microscope may be put down at 
£15, and for this sum a thoroughly efficient instrument 
can be obtained; while one that will answer every 
purpose may be bought for decidedly less. The cost of 
adapting a good stand will be about £6 tos. or £7 (30s. 
or £2 for the substage arrangement and £5 for the lens) 
or less if a cheaper oil immersion lens is obtained. 
It need scarcely be said that there are many ad- 
mirable microscopes other than those mentioned above, 
which have simply been selected as favourable and 
low-priced instruments of English and Continental 
manufacture. Amongst others, the microscopes made 
by Beck, Ross, and Watson are all good, and reasonable 
in price. 
STERILISATION OF APPARATUS, Etc. 
Requisites :—1. A thermometer graduated to 200° C. 
2. A hot air steriliser. 
oy A-cubical biscuit tin the soldering of which has 
been replaced by brazing. This must -be mounted 
upon a tripod stand. 
« ov A kitchen oven, preferably a gas oven. 
- 3. A steam steriliser. . 
ov A large kitchen steamer. This should be deep 
‘enough to contain a litre flask holding. a funnel. 
‘4. A large Bunsen burner or spirit-lamp. . = 
--Bacteria- and their spores are ubiquitous, and. jit: is 
