THE BACTERIOLOGICAL MICROSCOPE 3 



also supplies a portable instrument, the cost of which (without 

 lenses) is £^. This is very ingeniously made, and will carry an 

 oil-immersion lens quite well ; it is perhaps the most suitable 

 stand for a practitioner who may have to do work at a distance, 

 for it packs into a very small compass and is not heavy. The 

 same firm also make a microscope designed by Dr. Briscoe, 

 which is even more portable, has a mechanical stage, and packs 

 into a box in which all the requisites for blood-counts are carried. 

 It is especially adapted for blood-work at the bedside. 



Fig. 2. — Bacteriological Microscope. 



The cost of a ■^-^va.dh. oil-immersion lens is, roughly speaking, 

 £^. Beck and Watson supply good lenses at £d^. 



The cost of the other lenses may be put down at 30s. or less 

 apiece. Leitz's No. 3 (about f inch) costs 15s., and his No. 6 

 (about \ inch) costs 30s. ; these are both extremely well adapted 

 for bacteriological work. 



With regard to eye-pieces, it is an advantage to have two, a 

 No. 2 and a No. 4. Higher powers may be used, but it must be 

 remembered that any increased gain in magnification brought 



