1863.] 603 



longer time was coagulated only in a layer in contact with the 

 foreign solid. But in the latter case the blood had been so intro- 

 duced as to avoid direct action of ordinary matter on any but the 

 circumferential parts of it ; whereas in the former, though poured 

 quickly, it had run down the side of the glass, and as a con- 

 sequence of this almost momentary contact with the foreign solid, 

 the central parts, like the circumferential, underwent the process of 

 coagulation. 



Mysterious as this subtle agency of ordinary solids must appear, 

 its occurrence 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 spontaneous 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 pe- 

 culiarity 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 

 was now quickly inverted, and the vein was drawn off from over the 

 mouth of the tube, which was then covered with gutta-percha tissue 

 to prevent evaporation. After the inverted tube had been kept 

 undisturbed in the vertical position for nineteen hours and three 

 quarters, coagulable blood was obtained from the interior of the 

 clot. 



We have seen that a clot has but very slight tendency to induce 

 coagulation in its vicinity unless the blood has been acted on by an 

 ordinary solid ; and it is probable that with perfectly healthy blood 



