350 Veterinary Medicine. 



a period of six weeks. The virulence is rapidly destroyed by ex- 

 posure to free air and sunshine, by a high temperature (140° F.), 

 by dilute HCl (2:100), by carbolic acid (2:100), by zinc chloride 

 (5:100), by potassa; permanganas (10:100), by lime chloride 

 (4:100), or indeed by any of the strong antiseptics. 



Incubation. This extends from four to seven days on an 

 average, with a minimum of two and a maximum of twenty days. 

 The conditions favoring an early eruption are youth, high con- 

 dition, and a hot season, or close warm building, with overcrowd- 

 ing. Those favoring a tardy eruption are old age, debility, and 

 above all a cold or wet season with exposure in the open air. 

 Simonds, who inoculated in England in the cold months (October 

 and November) never saw it exceed 13 days. In certain cases, 

 however when the eruption had already commenced in mild 

 weather, the sudden occurrence of a week of cold and wet, 

 would stop it short to start anew on the return of warm weather 

 a week later. In inoculated cases the incubation is shortened, 

 while it is prolonged when the virus is introduced by the digestive 

 or respiratory passages. 



Symptoms. During the last two or three days of a prolonged 

 incubation and especially in old sheep, there may be some im- 

 pairment of appetite and rumination, dulness, a stiffness of 

 movement of the hind limbs, and a disposition to lag behind the 

 flock. The temperature may even have risen (104.5° F-)) yet 

 Simonds has never seen the febrile symptoms precede the eruption. 



There follow, trembling, or rigors, accelerated pulse (80 to 90) 

 and breathing, arched back, anorexia, suspension of rumination, 

 costiveness, redness of the eyes, epiphora, a watery discharge 

 from the nose, gradually becoming more viscid, and a marked 

 hyperthermia (105°, 106° or lo^'^ F.) If the skin is white, a 

 blush, with some heat, is shown in the seat of the future erup- 

 tion, usually on the parts uncovered by wool, the axillae, sternum, 

 abdomen, udder, inner sides of the thighs, lower surface of the 

 tail, and the face — especially the eyelids, nostrils and lips. 



In two days more, deep red points, like flea bites, appear more 

 or less numerously, in the congested parts of the skin, and in 

 twenty-four hours these have increased to firm rounded papules 

 which are felt to extend into the true skin. These vary in size 

 from 3 to 12 mm. or more. In two or three days the papule ha.s. 



