264 TRANSFUSION OF BLOOD IN THE HORSE. 
cessful with it as I was with a more simple apparatus. I 
fancied that the blood lost much of its vitality by being 
exposed to atmospheric action, and also by its being forced 
and compressed within the cylinder of the instrument. 
These impressions as to the cause of failure induced me to 
undertake several experiments, with a view to the con- 
struction of an instrument which would fulfil the requisite 
indications, viz., to allow the blood to pass freely from the 
vein of the healthy into that of the diseased subject without 
coming in contact with the atmosphere, and without alteration 
of its temperature. I at length adopted an exceedingly 
simple apparatus, which may be described in a few words. 
It consists of an India-rubber tube some tw 7 0-and-a-half feet 
in length, and three eighths of an inch in diameter — that is, 
about the calibre of the vein in the adult horse. To either 
end of this is fitted a silver tube, curved somewhat like a 
syphon, so that the end, which is slightly rounded at the 
point, might be passed easily into the vein, both tubes being 
exactly alike. A narrow zinc or tin trough is required to 
contain hot water, in which two thirds of the tube should 
be immersed during the time that the blood is flowing. This 
completes the apparatus, and, being prepared, and the horses 
ready, held by assistants, the jugular vein of the healthy 
horse, from which the supply is to be taken, may be opened, 
and into it one of the silver tubes carefully passed, point 
upwards, so as to receive the current of blood as it flows back 
from the head ; the operator holding the other end, and, 
having previously opened the corresponding vein in the 
patient, he should wait till the current is passing freely down 
the tube from the healthy horse, and then bring it in contact 
with that which is now flowing slowly from the patient ; he 
should pass the end of the tube carefully into the vein, point 
dowmwards, by which means the possibility of any air getting 
into the tube is avoided. The quantity to be transfused is 
readily ascertained by watching the expression of the eyes, 
and noting the pulse carefully. So long as there is no 
dilatation of the pupils, and so long as the heart’s action is not 
very much affected, the blood may be allowed to flow on un- 
interruptedly ; but as soon as the pupils become dilated, it is 
necessary to lessen the supply gradually, by compressing the 
tube with the finger and thumb. If the dilatation disappear 
after a minute or tw r o, the blood may be again allowed to 
flow ; but if it increases, further transfusion must be stopped, 
or otherwise injurious consequences will result. In the cases 
of two animals which I purchased for the purpose of ex- 
periment, I purposely allowed the blood to flow after the 
