60 THe MIcROSCcOPE. 
be much more to his credit to copy a description of his so-called 
invention, if he has any that was composed previous to seeing 
my improvement. He must understand that the suggestions of 
improvement are not patentable; but that they must be put 
into practical shape either by intelligable drawings, models or 
otherwise. 
If I have “ pirated ”’* McCalla’s “ form,” I certainly have 
not hidden my light under a bushel. I have given to the micro- 
scopic world the pirate spoils, which it might never have pos- 
sessed and enjoyed had it not been for my zeal in the persecution 
of the enterprize which had been so many years in developing ; 
and which only “ practical inventive genius”.could prepare for 
the public good. 
<q 
THE MEASUREMENT OF BLOOD-CORPUSCLES. 
Cc. H. STOWELL. 
Sees of our exchanges have had considerable to say lately 
about the size of the human red blood-corpuscle, and about 
the “standard measurements” in general. Mr. Vorce urges 
that we abandon the recognized standard measurement of this 
corpuscle as s200 of an inch. I do not think that this urging is 
at all necessary, for the “‘ standard measurement ” was dropped 
as such long ago. Mr. Vorce “ ventures the opinion that such 
a standard will be found to be nearer to s#s0 of an inch than is 
generally suspected.” 
I publicly ventured this same opinion over six years ago. 
It is stated in the first edition of my histology that my own ob- 
servations gave the s#:7 of an inch as the average size of these 
corpuscles. Now I believe that the size of the red blood- 
corpuscles of man is not far from sus of an inch. I also believe 
that a large number of measurements of the corpuscles of the 
dog will not vary greatly from this size even under the most 
favorable conditions. I cannot understand how it can be true, 
as Mr. Vorce says, that ‘“‘ between some observers the difference 
will amount to nearly five per cent.,” unless indeed the magni- 
fying power be comparatively low. With a cobweb eye piece 
micrometer and a # or ss objective, the measurements can be 
so delicate that an error of 5 per cent. can hardly be imagined 
* THE MICROSCOPE, page 30, February 1884. 
