G. H. Drew 
21 
specially obtained from Griibler & Co. : the ordinary Balsam in Xylol 
solution as used in most Laboratories will generally be found so acid 
that it will readily turn blue Litmus paper red, and is quite useless for 
this purpose. 
By this method a very fine differential staining of the corpuscles can 
be obtained, and such structures as “ eosinophil ” and other granules in 
the corpuscles are brought out with remarkable clearness. It has also 
the advantage that parasites and bacteria present in the blood take 
the stain well. On the other hand, any method in which the blood is 
removed from the body, and placed on a slide before fixation, is bound 
to result in a certain amount of distortion, and often agglutination, of 
the corpuscles. The only way to avoid this is to fix the corpuscles while 
still contained within their blood vessels, and this can be done by cutting 
out pieces of tissue, as small as possible, which contain lacunar blood 
spaces. Such pieces of tissue should be fixed for from 24 to 48 hours in 
Schaudinn’s solution, passed through the alcohols (without preliminary 
washing), embedded in Paraffin, cut into sections not exceeding 4 /a thick, 
taken down into distilled water, and then treated in the way described 
in paragraphs 4, 5, 6 and 7 according to the instructions given by Giemsa. 
Though by this process so much distortion of the corpuscles is not 
produced, still in many ways it is not so satisfactory as the former 
method. The blood cells are not expanded, and are often crowded 
together so that it is more difficult to distinguish details of structure, 
granules, etc. Though Giemsa’s stain, as applied to sections generally, 
does not give remarkably good nuclear images, yet it gives a degree of 
colour differentiation between various tissues, presumably corresponding 
to chemical differences in these tissues, which is frequently of great 
value, and it may often with advantage be employed for this purpose, 
in addition to its more specific use as a stain for protozoon parasites. 
