IQO BACTERIOLOGICAL DIAGNOSIS. 



little of the gum. The section is carefully removed 

 with a camel's hair -brush and placed in a 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 haematoxylin 

 (with or without eosin as a counterstain) and mounted 

 in balsam. 



The requisites are : Five watch-glasses containing 

 respectively haematoxylin, 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, 



