150 
The Application of 
obtained averages some what less than the truth. In this way only 
can I account for the circumstance that the measurements now 
published are somewhat larger than those in my former paper, 
although the same micrometer was used, and with the utmost 
care. 
Of course, since this source of error has been pointed out, it 
would be possible to measure the longest and shortest diameter of 
the elongated corpuscles in the microscope as well as on the 
photographs ; but it would require a much greater expenditure 
of time. 
It is my purpose, when time permits, to prepare' a series of 
photographs of moist blood, and of blood soaked out from dried 
stains, as in criminal cases. Perhaps I ought not to go so far as to 
say that no expert who goes into court to testify about blood-stains 
deserves to be listened to by a jury unless he takes with him pho- 
tographs of the blood examined on a stage-micrometer; but cer- 
tainly it must be admitted that hereafter the most trustworthy 
expert-testimony in such cases will be that which is corroborated 
by photographic evidence. The general introduction of this severe 
method of recording accurately the facts observed, is the more 
desirable, because of late a spirit of exaggeration seems to have pos- 
sessed certain experts, who either boldly claim, or in ambiguous 
language obscurely insinuate, that they possess the power of dis- 
criminating human blood from that of other animals in the dried 
stains which are submitted to examination in criminal cases. 
The latest offender in this direction is Malinin,* who published 
last year a paper in which, by the measurement of corpuscles soaked 
out from dried stains, he claims to distinguish not only between 
human blood and the blood of many other mammals, bnt, under 
certain conditions, between human blood and the blood of any other 
mammal, even the dog. To make out his case, Malinin assumes the 
invariable accuracy of Carl Schmidt's t mean values of the diameter 
of the blood-corpuscles of man and certain mammals, which he re- 
publishes without credit, as if they were his own. It is precisely 
this assumption of invariability which leads him astray. The truth 
is that not only do the individual corpuscles in every drop of blood 
vary considerably in size, but, as might be anticipated from this 
very fact, the average size obtained by measuring a limited number 
of corpuscles (50 to 175, still more in the case of but 10 to 50, as 
usually practised) varies considerably, not only between different 
* Malinin, " Ueber die Erkennung des menschlichen und thierischen Blutes 
in trockenen Flecken in gerichtlich - medicinischer Beziehung," Vircliow's 
' Arobiv,' bd. Ixv. (1875), s. 528. 
t Carl Schmidt, " Die Diagnostik verdachtiger Flecke in Ciiminalfallen." 
Mittau und Leipzig, 1848, When I published my former paper, as I tlien 
stated in a footnote, I had not been able to see a copy of this paper ; ljut one hap 
since been received at the Library of the Surgeon-General's Office. 
