2 BACTERIOLOGICAL DIAGNOSIS. 
made by a reliable firm, and in good condition, this 
should be sent to a maker (not necessarily the maker of 
the microscope in question) or to a bacteriologist for an 
opinion as to whether or no it is sufficiently firm and 
Fic. 1.—Bacteriological Microscope. 
has a fine adjustment good enough to justify the 
addition of the other parts. If this is the case it should 
be fitted with an Abbé’s condenser and an iris dia- 
phragm; the cost should not exceed 30s. or £2. But 
