THE THIRD HUXLEY LECTURE 537 



his view implied that the blood had a spontaneous tendenc}' to coagulate, which 

 was held in check b}- the active operation of the living tubes that contained 

 it.^ Facts such as I have just mentioned seemed to me to indicate that the 

 ordinary solid was the active agent, determining the formation of fibrine as 

 a thread does the deposition of sugar candy ; while the healthy living tissue 

 had the remarkable peculiarity of being destitute of this general aggregating 

 property of solids, behaving rather like the self-repelling particles of gases.- 

 It was not only in vessels of small size, like those of the sheep's foot, that 

 the blood remained fluid in parts severed from the body. I found that the same 

 was the case in veins of the dimensions of the jugular of the ox or the horse, 

 and this in spite of their entire detachment from surrounding structures. The 

 vessel being exposed after the animal had been felled at the abattoir, two ligatures 

 were applied in order to retain the blood in it, after which it was removed and 

 taken home with as little disturbance as possible. The blood in it retained 

 its fluidity for upwards of twenty-four hours, affording opportunity for most 

 instructive experiments. Of these I must content myself with describing 

 one. A portion of an ox's jugular with its contained blood being held vertically. 

 the upper part was removed along with its ligature, and the lips of the now 

 open venous compartment were held apart with forceps by aid of an assistant, 

 while a thin glass tube, of rather smaller calibre than the vein and open at both 

 ends, was passed down into the vessel with the utmost steadiness, so as to disturb 

 the blood as little as possible. The upper end of the tube had been drawn out 

 with the blow-pipe to much smaller size and a short piece of india-rubber tubing 

 adapted, so as to admit of clamping with catch-forceps. When blood appeared 

 at the end of the caoutchouc tube the clamp was applied. The whole apparatus 

 was then rapidly inverted and the piece of vein removed, leaving the blood 

 in a vessel of ordinary solid matter without any contact of living tissue. The 

 glass tube was steadily clamped to a retort stand, and its orifice covered with 

 a loose cap of gutta-percha tissue to exclude dust, after which all was left undis- 

 turbed for twenty-four hours. On then turning out the blood. I found it all 

 fluid except a layer of clot about one-eighth of an inch in thickness, which 

 encrusted the interior of the tube, and also a little clot at the surface, which 



' Briickc, of Vienna who had also competed for the Astley Cooper Prize, had arrived at a similar 

 conchision. He experimented hirgely with the turtle's heart, which, as in cold-blooded animals generally, 

 retains its life long after removal from the body ; the blood in its cavities at the same time retaining 

 its fluidity. I had not seen Briickc's important essay when the experiments referred to in the text 

 were performed. 



■ It has since been shown by Freund, of Vienna, that an indifferent liquid, such as liquid paraffin, 

 has a similar negative behaviour in relation to coagulation ; so that, by proper management, blood 

 may be kept fluid in a vessel of ordinary solid matter having its interior smeared with that substance. 

 Professor Haycraft arrived about the same time at a similar conclusion regarding castor oil. 

 msti;k II N n 



