Igo BACTERIOLOGICAL DIAGNOSIS. 
little of the gum. The section is carefully removed 
with a camel’s hair brush and placed ina large vessel of 
clean water so that the gum may be dissolved out of it, 
and is then ready for staining. The block is then raised 
by means of a very slight turn of the large milled head 
under the apparatus and another section cut. 
The mass must not be frozen too hard; if this has 
been the case the necessary thawing will be hastened 
by gently breathing on the block. If it begins to thaw 
a few squeezes of the bellows will bring it to the proper 
consistency. 
STAINING AND MOUNTING FROZEN 
SECTIONS. 
These processes are best carried out in watch-glasses. 
No attempt will be made to describe the methods by 
which frozen sections may be stained for the purposes of 
bacteriological research, for they are not so suitable as 
paraffin sections for this purpose. We shall describe 
the process which would be adopted if a rapid diagnosis 
were required at an operation or in the post-mortem 
room. The sections are to be stained in hematoxylin 
(with or without eosin as a counterstain) and mounted- 
in balsam. 
The vequisites are:—Five watch-glasses containing 
respectively hamatoxylin, watery solution of eosin 
{about one per cent.), alcohol (50 per cent.), absolute 
alcohol, and clove oil; a saucer or other vessel contain- 
ing water to which a few drops of ammonia have been 
added; several strips of thin writing paper, each about 
one inch wide and two inches long; some needles, 
