1863.] 



601 



But it may pernaps be argued by those who say that the blood- 

 vessels are active in maintaining fluidity, that the small portion of 

 the vein covering the end of the tube was acting upon the blood, 

 which certainly was fluid where in contact with it, the clot being in 

 the form of a tube open at the lower end. To guard against such an 

 objection I made the following experiment : I extended a tube like 

 that above described by means of thin sheet gutta percha, G (fig. 6 a), 



Fig. 6. 



contriving that the internal surface of the gutta percha should be per- 

 fectly continuous with that of the glass tube as represented in section 

 in fig. 6 b. The lower part of the gutta-percha tissue was strength- 

 ened by a ring of soft flexible wire such as is used by veterinary sur- 

 geons for sutures, and the wire W was also extended upwards to the 

 top of the glass so as to maintain the rigidity of the gutta-percha 

 portion during its introduction into a vein, but at the same time, from 

 its softness, permit the gutta-percha part to be bent at a right angle 

 after it had been introduced, and so close the orifice of the glass tube 

 with ordinary solid matter. In fig. 6 c the tube is represented 

 pressed down by a weight in a vein V, with blood B in the glass 

 portion, while the gutta-percha part closes it below. At the same 

 time I performed a comparative experiment, to which I would invite 

 particular attention, although I am sorry at this late hour to occupy 

 the attention of the Society so long. I tied a thin piece of gutta- 

 percha tissue over the lower end of a similar glass tube, and simply 



