1 1 8 Veterin a ry Medici n e . 



cities the outbreak could in nearly every case be traced to horses 

 just arrived from a pre-existing centre of infection. In Detroit, 

 Syracuse and Chicago it spread first in stables that had just re- 

 ceived Canadian horses, in Ithaca in one which had received 

 horses from an infected centre in Northern New York and in 

 Pittsburg and Washington in stables that had just admitted horses 

 from infected New York. 



3d. It advanced with much greater rapidity eastward than 

 westward, being in the line of greatest horse traffic, the animals 

 being mainly raised and fitted in the West and shipped in large 

 numbers to the great cities near the Atlantic seaboard. 



4th. In the absence of this active railway traffic in horses, the 

 advance was most rapid through other lines. In Pa., in a number 

 of valleys opening to the south, the disease reversed its general 

 direction, and extended northward up these valleys. In Lehigh 

 Co., Pa., it followed the course of the canal, being carried by 

 horses and mules employed on the towpath. In Davidson and 

 Sumner Cos., Tenn., it followed the track of a circus which came 

 through an infected locality. It reached the Pacific coast at 

 Santa Barbara (not at the railway terminus at San Francisco) 

 having followed a mule stage route in the absence of an active, 

 westward progress of horses by rail. 



5th. The affection failed to overstep any serious gap over 

 which there was no movement of equine animals. It prevailed 

 in Victoria, B. C, in July, but, owing to a strict quarantine on 

 horses and mules, it failed to reach Vancouver Island. It ravaged 

 New Brunswick and Nova Scotia in November but failed to reach 

 Prince Edward Island which was then ice bound and shut off 

 from all traffic with the mainland. It ravaged Cuba to which it 

 was brought by American horses landed at Havana, but no other 

 West Indian island was attacked. Its southward course was 

 finally arrested at Central America, where horses are few and 

 horse traffic nearly unknown. 



Every fact in connection with its eruption and progress agrees 

 perfectly with the hypothesis of transmission by contagion alone, 

 and taken altogether the history excludes all other causes from 

 being anything more than accessory. Before the days of modern 

 bacteriology we had ample proof that glanders, rabies, sheep-pox, 

 lung plague, and Rinderpest were due to contagion alone as an 



