and those of certain other Mammals. 
75 
dried on glass, as is generally practised in making preparations of 
blood for permanent preservation. In such preparations the cor- 
puscles have almost exactly the size they possess in the perfectly 
iresh blood. The great majority of Mr. Gulliver's measurements 
were made upon blood prepared by this method, and at the time he 
appears to have regarded the results as the equivalent of measure- 
ments made on perfectly fresh blood. " In some instances," he 
tells us, " there v^as certainly a slight enlargement in the dried 
corpuscles, as compared with those seen in their own serum imme- 
diately after they were taken from the animal. In the greater 
number of trials, however, the sizes of the wet and dry disks corre- 
sponded accurately." * Twenty years later he seems to have 
modified this opinion somewhat, for he states, "When the cor- 
puscles of man and other mammalia were dried on glass, however 
quickly, they were usually just appreciably larger than in the 
liquor sanguinis."! Welcker also found that the mean dimensions 
obtained by measuring the corpuscles dried in a thin layer was apt 
to be rather greater than that obtained from the measurement of 
moist blood, and explains it by stating that " the very smallest, 
mere spherical corpuscles spread out a little in drying." He regards 
the difference, however, as so trifling, that he uses measurements of 
dried specimens indiscriminately with those of moist in obtaining 
his average. I myself am not satisfied that there is any constant 
difference, and find, on comparing the mean diameter of fifty cor- 
puscles dry, with fifty moist, from the same individual, that some- 
times the one, sometimes the other, is a trifle the largest. The 
dried corpuscles are very apt to be deformed, and often many of 
them are quite oval. If the long diameters of a number of such 
corpuscles are measured, the mean will be of course too great. 
I do not find it so if the measurement is confined, as it should be, 
to those corpuscles which have dried systematically and are quite 
circular. How is it, now, with regard to blood dried en masse 
when sprinkled upon weapons, clothing, wood, &c. Dr. Kichardson 
admits in this case that a slight contraction takes place, but evidently 
regards it as too trifling to interfere with the diagnosis. Carl 
Schmidt, on the other hand, found the blood-corpuscles under such 
circumstances contracted to nearly one-half their original size ; and 
gives • 0040 mm. as the mean diameter of the corpuscles of human 
blood thus prepared, while he assigns • 0077 mm. as the mean of 
human corpuscles dried in thin layers on glass4 It is not necessary 
for the purpose of the present paper to go into a detailed discussion 
of this subject, for no one will pretend that it can be any easier to make 
the diagnosis of such stains than it is in the case of moist blood or 
* 'London and Edinburgh Philosophical Magazine,' vol. xvi. (1840), p. 25. 
t ' Medical Times and Gazette,' August, 1862, p. 158. 
X I quote from Fleming, op. cit., p. 111. 
VOL. XIII. G 
