ON THE COAGULATION OF THE BLOOD £27 
squeezed from it yielded no threads of fibrine, coagulation being complete. How 
long it had been so I do not know. I did not examine the other blood until 
seven hours and three quarters had expired, and then found that, just as in 
the cases where a simple glass tube was introduced, the clot was tubular, and 
the chief part of the blood was still fluid in its interior, the only difference being 
that in this case the clot formed a complete capsule, being continued over the 
gutta-percha instead of being deficient below, as it was when the vein closed 
the end of the tube. Now if we consider the two parts of this comparative 
experiment, we see that the receptacles in which the blood was ultimately con- 
tained were precisely similar in the two cases, viz. glass tubes closed below 
with gutta-percha ; and that the blood which was simply poured into the tube 
was much less exposed to the air than the other, and also was not subjected, 
like it, to elevation of temperature, a circumstance which promotes coagulation ; 
but yet this blood became completely coagulated in a comparatively short time, 
whereas the other after a much longer time was coagulated only in a layer in 
contact with the foreign solid. But in the latter case the blood had been so 
introduced as to avoid direct action of ordinary matter on any but the circum- 
ferential parts of it, whereas in the former, though poured quickly, it had run 
down the side of the glass, and as a consequence of this almost momentary 
contact with the foreign solid, the central parts, like the circumferential, under- 
went the process of coagulation. 
Mysterious as this subtle agency of ordinary solids must appear, its occur- 
rence is thus matter of experimental demonstration, and by it the coagulation 
of blood shed into a basin is accounted for ; while it is also shown conclusively 
from this experiment that the blood, as it exists within the vessels, has no spon- 
taneous tendency to coagulate, and therefore that the notion of any action 
on the part of the blood-vessels to prevent coagulation is entirely out of the 
question. The peculiarity of the living vessels consists not in any such action 
upon the blood, but in the circumstance, remarkable indeed as it is, that their 
lining membrane, when in a state of health, is entirely negative in its relation 
to coagulation, and fails to cause that molecular disturbance or, if we may so 
speak, catalytic action which is produced upon the blood by all ordinary matter. 
I afterwards found that the simplest method of maintaining blood fluid 
in a vessel composed entirely of ordinary matter was to employ a glass tube 
similar to those above described, except that its upper end was closed by a cork 
perforated by a narrow tube terminating in a piece of vulcanized india-rubber 
tubing that could be closed by a clamp. This tube was slipped down into a vein 
till the blood, having filled it completely, showed itself at the orifice of the india- 
rubber tubing, to which the clamp was then applied. The whole apparatus 
