PURPURA H.EMORRHAGICA. 73 



ing influenza more frequently than any of the other 

 diseases named. Filthy and improperly ventilated stables, 

 impure air, etc., highly predispose, and may prove the 

 exciting causes of purpura ; and sudden changes, as alterna- 

 tions of temperature while suffering from another disease, 

 as influenza, etc., has a tendency to produce it, as has put- 

 ting an animal to work too soon after previous disease, 

 and while in a debilitated condition. 



Sym];jtoms. — Often the first symptom noticed is swelling 

 of one or both hind legs, usually occurring in the neigh- 

 bourhood of the hock. On walking the animal out the 

 swelling is observed to disappear ; its disappearance, how- 

 ever, is only temporary, as in an hour or so it is again 

 observed, but possibly in another limb. The swelling is 

 very characteristic, appearing as though a cord was tied 

 around the limb in such a manner as to interfere with the 

 circulation. The swelling is due to the extravasation of 

 blood and serum which has taken place. All the visible 

 mucous membranes are covered with patches of ecchymosis, 

 purple in colour, and of various sizes, in some cases not much 

 larger than a pin-head, but growing larger, and often becom- 

 ing confluent, and causing sloughing of the mucous membrane 

 to such an extent that in some cases the disease might be 

 mistaken for glanders. The pulse varies in character : in 

 some cases being much quickened, while in other cases it is 

 not very much increased in frequency. The slightest 

 change in the weather will produce rigors. The temperature 

 suddenly becomes elevated to about 104° — 106' Fahr., and 

 in some cases even exceeds the highest point mentioned. 

 There may be observed swelling of the eyelids, and of the 

 lower lip, which latter is tense and stiff, and has a glisten- 

 ing appearance ; the eyelids may in some cases be everted. 

 The swelling may occur in the fore-legs, but is more 

 commonly found occurring in the hind-legs. When the 



