8 DISEASES OP THE HOESE. 



HISTORY. 



It is important to know, first of all, something of the origin and 

 development of the disease ; therefore the cause should be looked for. 

 The cause of a disease is important, not" only in connection witli diag- 

 nosis, but also in connection with treatment. The character of feed 

 that the hoi-se has had, the use to which he has been put, and the kind 

 of care he has received should all be closely inquired into. It may be 

 found by this investigation that the horse has been fed on damaged 

 feed, such as brewers' grains or moldy silage, and this may be suffi- 

 cient to explain the profound depression and weakness that are char- 

 acteristic of forage poisoning. If it is learned that the horse has 

 been kept in the stable without exercise for several days and upon 

 full rations, and that he became suddenly lame in his back and hind 

 legs, and finally fell to the ground from what appeared to be partial 

 paralysis, this knowledge, taken in connection with a few evident 

 symptoms, will be enough to establish a diagnosis of azoturia (excess 

 of nitrogen in the urine). If it is learned that the horse has been 

 recently shipped in the cars or has been through a dealer's stable, 

 we have knowledge of significance in connection with the causation 

 of a possible febrile disease, which is, under these conditions, likely 

 to prove to be influenza, or edematous pneumonia. 



It is also important to know whether the particular horse under 

 examination is the only one in the stable, or on the premises, that is 

 similarly afflicted. If it is found that several horses are afflicted 

 much in the same way. we have evidence of a common cause of 

 disease which maj^ prove to be of an infectious nature. 



Another item of importance in connection with the history of the 

 case relates to the treatment that the horse may have had before he 

 is examined. It sometimes happens that medicine given in excessive 

 quantities produces symptoms resembling those of disease, so it is 

 important that the examiner be fully informed as to the medication 

 that has been employed. 



ATTITUDE AND GENERAL CONDITION. 



Before beginning the special examination, attention should be 

 paid to the attitude and general condition of the animal. Sometimes 

 horses assume positions that are characteristic of a certain disease. 

 For example, in tetanus (lockjaw) the muscles of the face, neck, and 

 shoulders are stiff and rigid, as well as the muscles of the jaw. 

 This condition produces a peculiar attitude, that once seen is subse- 

 quently recognized as rather characteristic of the disease. A horse 

 with tetanus stands with his muscles tense and his legs in a somewhat 

 bracing position, as though he were gathered to repel a shock. The 

 neck is stiff and hard, the head is slightly extended upon it, and the 



