HENDRY, ON TEICHMANN’S BLOOD-CRYSTALS. 169 
. My own hitherto limited experience would induce me to 
place as much reliance upon the one method as the other 
(English as Continental), as regards ordinary quantities, but 
we have the authority of Virchow to the purport that, “in 
cases in which the ordinary chemical tests would necessarily 
fail on account of the smallness of the quantity, we are still 
able to obtain heematine.” Again, ‘‘ These forms (crystalline) 
have proved of very great importance in forensic medicine on 
account of their having been employed as one of the surest 
tests for the examination of blood-stains.” I myself, says 
Virchow, have been in a position to make experiments of 
this sort in forensic cases; and he further asserts that in the 
case of a murdered man, on the sleeve of whose coat “blood had 
spurted, and where some of the drops were only a line in 
diameter, he had been able from these minute specks to 
produce innumerable crystals of hematine—of course micro- 
scopical ones.” 
Now, it appears to me that Virchow himself is unfortu- 
nately rather loose in the expressions, ‘‘ some of the drops,’ 
“from these minute specks,” &c., where it is intended to 
imply a minimum quantity of material under manipulation, 
for a multiplicity of drops, of each a line in diameter, might 
afford a quantity amply sufficient for comparison. However, 
Iam myself willing to suppose that a quantity of material 
covering aspace not exceeding about ;th or ;;th of an 
English inch in length as well as in breadth, may furnish 
ample means of producing abundance of the crystals in ques- 
tion, as readily as a number of drops or even an indefinite 
continuous Jine of blood-deposit. 
Kolliker likewise states, ‘‘ the interest of these crystals has 
recently been greatly enhanced, from their having been used 
by Briicke in the diagnosis of blood spots.” 
So far, therefore, as authority goes, as to the importance 
of Teichmann’s crystals, there is nothing wanting, yet there 
are a few matters to be understood concerning the distinc- 
tions necessary to be observed between the crystals obtained 
from the colouring matter of blood, whether produced spon- 
taneously or artificially, or whether formed in or out of the 
body. Y 
Jones and Sieveking figure crystals of hematine as elon- 
gated rectangular tablets, which vary very much in size, and 
are coloured more or less deeply by red matter (edit. 1854, 
p- 91) such are of pathological import. 
Hematoidine crystals are formed in the body out of heema- 
tine, in the form of oblique rhombic columns or plates, some- 
times resembling uric acid crystals, common to apoplectic 
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