220 THE Microscope. 
fully confirms Dr. Woodward’s statement, quoted by Dr. Up De 
Graff, in your magazine of December, 1883: 
‘‘The average of all measurements of human blood I have made 
is rather larger than the average of all measurements of dog’s blood. 
But it is also true that it is not rare to find specimens of dog’s blood in 
which the corpuscles range so large that the average size is larger than 
that of many samples of human blood.” 
I do not mean to say that I can meet with a like practical 
demonstration the statement in regard to thickness of cell wall, 
etc., because negative testimony in this respect, might only 
serve to show incapacity of manipulation on my part; but I 
must say, that so far as I know, his, Dr. Up De Graff’s results 
in these respects are wholly confined to himself, and I will take 
the liberty of adding, in the language of the compeers of M. 
Baruel: “ It is true that M. Baruel is able to distinguish between 
the blood of the various species of animals by its odor! But 
this test has a somewhat hypothetical value for scientific pur- 
poses. The point of admiration belongs to the original.” 
In a note on page 212 of the magazine, the Dr. further says: 
‘‘Tt is presumed to be an admitted fact, that the blood corpuscles 
of the horse, cow, pig, sheep and goat, being so much smaller than 
man’s, their identification is easy of procurement.’’ 
Now I deny all this most absolutely. I do not believe that 
a single scientist, with the exception of Dr. Up De Graff and M. 
Baruel, makes any such claim whatever. If we find blood cor- 
puscles which average as much larger than these, as do those of 
man, we could say that they did not come from these animals, 
and that they might be from the human animal, or from dogs, 
etc., but there is no such thing as “identification ” in all this. 
As between the blood of these animals and human blood, if 
we are confined to such question, and the corpuscles were of the 
average size of the human, we could of course pronounce abso- 
lutely ; but not the negative of this if they chanced to be small 
like the corpuscles of these animals, for under certain conditions, 
as I have found in my experiments, blood corpuscles shrink a 
good deal in drying. These conditions are well known however, 
and do not very often exist. It is a settled fact, thus far, that 
blood corpuscles in drying upon any hard substance do not 
shrink in the least degree. The fact of shrinking in any case 
would not affect the question in which the blood under exami- 
