Tae MuicroscopicAL News 
AND 
NORTHERN MICROSCOPIST. 
No. 38. FEBRUARY. 1884. 
MICROSCOPICAL EVIDENCE CONCERNING 
BEOOD CORPUSCLES: 
ROM reports which have come to us through the newspapers 
we have very meagre knowledge of the circumstances under 
which a gentleman, well-known to the readers of this Journal, 
has testified in a recent trial that certain spots found upon a 
coat were produced by human blood. ‘The evidence given, as we 
have learned from the published reports, was of a nature to 
influence the result of the trial, and as it seems to have been of 
a very positive nature we must presume that the attendant cir- 
cumstances were such as to fully justify it, for, at the present time, 
it seems rash, to say the least, to venture very positive testimony 
founded upon measurements of blood corpuscles alone. In other 
words, if, in the case referred to, it were conclusively shown that 
the stains could not have been produced by the blood of some 
animal whose blood-cells are almost the same as those of man, 
then the microscopical evidence would be sufficient to prove the 
nature of the stain, and to distinguish the blood-cells from those 
of birds, etc. But, on the other hand, we have grave doubts, 
which are shared by many microscopists of experience, if the shape 
and size of the cells of dried blood, obtained from woven fabrics by 
soaking in mercuric chloride, or in any other way, are sufficiently 
characteristic to justify any positive evidence of their origin, based 
upon our present knowledge and experience. 
We do not express the opinion that it is impossible to distinguish 
the different kinds of corpuscles in this way. On the contrary it 
seems very probable that itcan be done. ‘There seems to be great 
constancy in the average sizes of the corpuscles of different animals, 
and, providing a sufficient number of them are measured to get a 
fair average size, there is no doubt of our ability to distinguish 
different specimens of fresh blood with absolute certainty. But in 
dealing with dried blood, especially such as is dried upon cloth, or 
fibrous surfaces, the corpuscles are likely to be distorted, and it is 
VOL. IV. 
