406 DaDD'S veterinary medicine and surgery. 



possibility of any air getting into the tube is avoided. The quan- 

 tity to be transfused is readily ascertained by watching the expres- 

 sion 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 uninter- 

 ruptedly ; 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 ' i 

 two, the blood may be again allowed to flow ; but if it increases, 

 further transfusion must be stopped, or, otherwise, injurious con- 

 sequences will result. 



In the cases of two animals which I purchased for the purpose 

 of experiment, I purposely allowed the blood to flow after dilata- 

 tion of the pupil had manifested itself, in order that I might see 

 the result, and I found it to increase ; and in one of the cases, 

 after winking both eyes three or four times, in rapid succession, 

 the horse reared up and fell back. In the other case, I forced the 

 blood in from an India-rubber enema bottle. The pupils firut 

 became still more dilated ; the breathing very quick and difficult ; 

 the eyes assumed a wild, agonized look, and the animal, with a 

 sudden bound, fell forward dead. I had my finger on the artery 

 during the entire time, and observed a great unsteadiness and flut- 

 tering of the pulse, which increased in frequency until the instant 

 before he fell. In the first of these cases, I did not force the blood 

 into the vein, but allowed it to flow until I perceived the injurious 

 effects upon the horse. He tottered and fell, but in a short time 

 recovered, and was walked back to his stable. He died in the 

 course of the night, and, on examining his head the next day, I 

 found considerable congestion of the brain. The tube used for 

 the experiments transferred about three quarts of blood in eight 

 minutes; at least it might be so inferred, from the fact that when 

 used a*> a syphon, it passed three and a half quarts of water (and 

 r. little less of oil) from one vessel to another in that time. 



I think, however, that I am correct in saying that this disease 

 is by no means so likely to occur in horses as in human beings, and 

 is certainly not so formidable ; but, nevertheless, I am quite sure 

 that it may happen as a consequence of the operation, if the instru- 

 ment be not kept scrupulously clean, and also if great care bo not 

 taken in its introduction in the vein. Having, from these and 

 other experiments, not necessary to detail, determined on the mode 



