[ 400 ] - 
from his arm. This quantity was divided into 
four portions ; the fiift was received in a cup, and 
was in meafure little more than an ounce ; the 
fecond, in a bafon, to the quantity of two ounces; 
the third, in a cup, which’ held one ounce; and the 
fourth, in a bafon, to the quantity of three ounces. 
Each velfel was placed immediately upon the 
window ; and it was obferved that the blood in the 
firft was lateft in coagulating, and had a cruft over 
the whole furface ; that in the fecond, had a cruft 
only upon a part of its furface; but that in the third 
and fourth had no cruft, and manifeftly coagulated 
before either of the other two. 
From thefe experiments it is evident, that the 
properties of the coagulable lymph can be foon 
changed ; fince, in the fpace of three or four mi- 
nutes, the difpolition to coagulate was increafed, and 
probably too the lymph was thickened. Jt might 
indeed, at fir ft fight, feem poffible, that blood-letting 
had only let out the vitiated part ; but this is highly 
improbable ; for, fuppofe a part only of the blood 
was vitiated, that part muft have been equally dififufed 
through the whole mafs, and there is no likelihood 
of its getting out of the veflels before the reft of the 
blood ; and confequently it ought to have appeared in 
thelaft equally as in the firft cup, but it did not. Bleed- 
ing, therefore, in thofe cafes alters the nature of the 
blood, not by removing the vitiated part, and giving 
room for new blood to be formed, as has been 
fufpe&ed ; but probably by changing that ftate of 
the blood-velfels on which the thinnefs, and lelfened 
tendency of the lymph to coagulation, depends ; 
which furely is a very curious circumftance. This 
fadt 
