366 BUREAU OF ANIMAL INDUSTRY. 



always be suspected when the following history is known: The gen- 

 eral 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 per- 

 manent, 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, ver}^ soon 

 begin to slacken his pace and to show signs of the trouble, and if 

 urged to increase his speed will become lamer and lamer; an aV)andant 

 perspiration will break out; he will refuse to go, and if forced he 

 shows weakness 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 sjmiptoms will gradually subside, some- 

 times very soon, and occasionally after a few hours he will return to 

 an apparently perfect condition. A return to labor will lead to a 

 renewal of the same incidents. 



A history like this suggests a strong suspicion of a thrombus in an 

 artery of the hind leg, and this suspicion will be confirmed b}' the 

 external symptoms exhibited by the animal. The total absence of 

 any other disease which might account for the lameness, and a mani- 

 fest diminution of heat over a part or the whole of the extremity, 

 when compared with the opposite side or with anj^ other portion of 

 the bod}'; a sensation of cold attendant on the pain, but gradualh' 

 subsiding as the pain subsides, and the circulation, quickened by the 

 rest, has been reestablished throughout the extremity; all these are 

 confirmator}^ circumstances. Still, it is thus far only a suspicion, and 

 absolute certainty is 3'et wanting. To establish the truth of the case the 

 rectal exploration must be resorted to. The hands then, well prepared 

 and carefully introduced into the rectum, must explore for the truth, 

 first feeling for the large blood vessels which, divided at the aorta, 

 separate to supph^ 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 

 cord)', and 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 circulation through an unobstructed 

 channel, the other a forced passage of the fluid between the thrombus 

 and the coats of the arter}'. In such a case the prognosis is necessaril}' 

 a grave one and the disease is more liable to grow^ worse than better. 



Treatment. — No form of treatment can be advised; and the suffering 

 of a helpless and useless animal can onl}' be terminated by that which 

 ends all. 



