Mr. F. Galton's Experiments in Pangenesis. 



387 



drachms, indicated by the graduations on the syringe-handle, (12) 

 returned the overphis to the glass of supply-blood, (13) cleansed 

 syringe and injected water, (14) let the rabbit bleed three or four 

 drachms, — and then recommenced the series. I have not reinserted 

 in this description before (11) and (13) what I previously described 

 about turning the stopcock &c. ; nor have I spoken of the continual 

 jotting down of notes in my case-book. 



At the end of all, the vein was tied. It was, no doubt, the surest 

 plan to avoid future hemorrhage, especially as the blood was de- 

 fibrinized ; but the rabbits were apt to suffer from phlebitis, and I 

 lost some thereby. 



Owing to the extreme rapidity and stiffness of the coagulation of 

 rabbit's blood, it is quite easy to estimate the quantity that may have 

 been spilt on the operating-table. It has simply to be sponged 

 into a measuring-glass. 



Cross-circulation would be a very easy operation in animals whose 

 carotids were even a trifle larger than those of silver-grey rabbits ; 

 but it is difficult with these, because the smallest cauula which can 

 be used with propriety can only just be forced into the largest of 

 them. It is of no use to operate with small canulae ; in every case, 

 a layer of fibrine is sure to line the tube ; if the bore is small this 

 layer chokes it, while a layer of equal thickness in a larger tube 

 leaves a free central passage. I found canulse -^ inch in diameter 

 of bore were worthless ; those I used were ^ inch. If I were to 

 operate again, I should not use silver-grey rabbits, on account of 

 their smallness, but " Belgian hare " rabbits. When the canulae 

 are brought home together, the wire hooks, shown in the sketch, 

 secure them ; but I also slipped an India-rubber band over the tips of 

 their handles. The cut ends of the artery were held open and 

 stretched out by a pair of delicate curved forceps (a suggestion due to 

 Dr. Murie), and the canula was pressed in (the shape of its mouth 



was the result of many trials and modifications), and a ligature vn 



