354 



larger trunks a strong suspicion of their presence may be excited. In 

 some cases they may even be recognized with positive accuracy, as 

 when the vessels which supply the posterior extremities are affected by 

 the blocking up of the posterior aorta or its ramifications. 



The existence of embolisms of the arteries of the hind leg may always 

 be suspected when the following history is known : The general health 

 of the animal is good, but symptoms of lameness in one of the legs have 

 been developed, becoming more marked as he is worked, and especially 

 when driven at a fast gait. But the disturbance is not permanent, and 

 the lameness disappears almost immediately upon his being permitted 

 to rest. There is an increase of the difficulty, however, and, though he 

 may walk normally, he will, when made to trot, very soon begin to 

 slacken his pace and to show signs of the trouble, and if urged to in- 

 crease his speed will become lamer aud lamer ; an abundant perspira- 

 tion will break out; he will refuse to go, aud if forced he shows weak- 

 ness behind ; seems ready to fall, and perhaps does fall. While on his 

 feet the leg is kept in constant motion, up and down, and is kept from 

 the ground as if the contact was too painful to bear. If undisturbed 

 this series of symptoms will gradually subside, sometimes very soon, 

 and occasionally after a few hours he will return to an apparently per- 

 fect condition. A return to labor will lead to a renewal of the same 

 incidents. 



A history like this suggests a strong suspicion of embolism of an 

 artery of the hind leg, and this suspicion will be confirmed by the ex- 

 ternal symptoms exhibited by the animal. The total absence of any other 

 disease which might account for the lameness, and a manifest diminu- 

 tion of heat over a part or the whole of the extremity, when compared 

 with the opposite side or with any other portion of the body; a sensa- 

 tion of cold attendant on the pain, but gradually subsiding as the pain 

 subsides, and the circulation, quickened by the rest, has been reestab- 

 lished throughout the extremity; all these are confirmatory circum- 

 stances. Still, it is thus far only a suspicion, and absolute certainty is 

 yet wanting. To establish the truth of the case the rectal taxis must 

 be resorted to. The hands then, well i^repared and carefully introduced 

 into the rectum, must explore for the truth, first feeling for the large 

 blood vessels which, dividing at the aorta, separate to supply the right 

 and left legs. These must be compared in respect to the pulsation and 

 other particulars. The artery which is health^' will of course exhibit 

 all the proper conditions of that state. On the other hand, if the vessel 

 appears to the feel hard, more or less cordj^, aud pulseless, or giving a 

 sensation of fluttering, as of a small volume of blood with a trickling 

 motion passing through a confined space, the difference between the 

 sides will make the case plain. The first will be the full flow of the cir- 

 culation through an unobstructed channel, the other a forced passage 

 of the fluid between the embolism and the coats of the artery. 



