DETECTION OF THE SEAT OF LAMEKESS. 23 



cause is found to explain the lameness, or the absence of 

 such a cause is established beyond a doubt. 



2. The duration of the lameness and the natiire of any- 

 anatomical change are to be compared. If the lameness is of 

 recent origin and the pathological condition an old one, or 

 when the lameness is of long standing and the pathological 

 condition of recent date, it is clear that one cannot be 

 directly connected with the other. 



3. Compare the influence which the present abnormality 

 has upon the physiological functions of the limb with the 

 nature of the existing functional disturbance. 



Splints and thrush are frequently looked upon as causes 

 of lameness, but an exostosis only causes lameness when 

 periostitis is present, recognized by palpation, or when such 

 an exostosis mechanically obstructs the movement of a 

 joint. Thrush rarely causes lanieness, excepting in 

 contracted feet,— the latter, in my mind, being the main 

 cause of lameness ; but thrush itself will cause lameness 

 whenever the horny frog is destroyed to such an extent that 

 it no longer protects the sensitive frog from undue pressure. 

 Generally lameness is accompanied by distinct anatomical 

 changes, and the seat of it can thus be located ; but 

 lameness depending on paralysis does not show any 

 anatomical changes at first; the diagnosis therefore is based 

 upon the functional disturbance and the absence of pain. 



For a number of years hypodermic injections of 

 cocaine over the plantar nerves at the fetlock have been 

 resorted to, to help locating the seat of the lameness, 

 especially in cases of mixed lameness, whoe doubt prevailed 

 as to whether the pathological conditions above or below 

 the fetlock caused the lameness. As a rule, 5 to 10 drops of 

 a 10 per cent, solution of cocaine were iujected on either side 



