82 SMAhL-POX IN SHEEP. 



period of its duration. In natural cases, even when mild, 

 and when no cause retards their completion, a month, 

 reckoning from the period at which the animal was 

 first exposed to the contagion, usually passes before it 

 is restored to health. 



The following summaiy of the gi'adations of the 

 malady may be accepted as sufficiently accurate for 

 practical purposes : — The first ten or eleven days are 

 those of incubation; the twelfth and thirteenth, of 

 invasion ; the fourteenth, fifteenth and sixteenth, of 

 'papulation ; the seventeenth, eighteenth and nine- 

 teenth of vesication; the twentieth, twenty-first and 

 twenty-second, of suppuration ; and the twenty-third 

 to the twenty-eighth, of desiccation and separation of 

 the crusts. 



Having described the local appearances, we shall 

 now speak of the constitutional symptoms of the 

 affection, and point out those which indicate the 

 gi-eatest danger to the patients. The infected sheep 

 separate themselves from their fellows, and mostly lie 

 down in a remote corner of the field : they exhibit a 

 peculiar, dejected condition ; the head is held low ; 

 the ears are pendent ; the breathing is quick and short ; 

 the eyelids are swollen, and tears trickle down the 

 face ; the conjunctiva varies in shade fi'om a bright 

 scarlet to a modena red ; a mucous discharge flows 

 from the nostrils, and increases in \'iscosity as the disease 

 advances, often becoming sanguineous in the latter 

 stages : yellowish spots, mucous vari, may likewise be 

 seen scattered here and there on the pituitary mem- 

 brane ; the pulse early gives evidence of febrile exci- 

 tation ; at first it is quickened and somewhat increased 

 in force, numbering about 95 beats in a minute ; later 



