INFLUENZA IN HORSES. 209 



November 21 the streefc-cars in Augusta, Georgia, were stopped, aud 

 the first thirteen cases occurred at Martha Furnace, Blair County, Penn- 

 sylvania. Xovember 24, fifty horses and mules were attacked at once 

 at Johnstown, Cambria County, Pennsylvania. 



November 27 the street-cars were stopped at Halifax, 'Sova Scotia, 

 on account of the disorder ; it was reported to be spreading rapidly in 

 ISTew Orleans ; and had appeared in Jacksonville, Illinois, Keokuk, Iowa, 

 and Montgomery, Alabama. 



November 28 it was reported at Jacksonville, Florida ; November 30 

 it prevailed in Fulton County, Georgia, and Newberry County, South 

 Carolina, making a westward progress. 



December 2 it broke out in East Saint Louis, Missouri ; December 3, 

 in Boonville, Missouri, and Omaha, Nebraska. 



December 7 it reached Havana, Cuba, attacking native aud northern 

 horses alike. On December 14 it had reached its height, many horses 

 were dying, and Mexican horses were being imported by the Spanish 

 government. 



The outbreak has varied widely in its nature at different places. 

 Sometimes it has spread slowly along the course of railroads or turn- 

 pikes, and its progress can be very satisfactorily connected with the in- 

 tercourse between the different places attacked. In other cases it 

 appears, from the reports, to have struck down a whole city or limited 

 district in twelve or twenty- four hours, and in a manner which it appears 

 impossible to account for otherwise than by some subtle and generally 

 pervading influence. The earliest reports of the disease from many 

 points allege that colts, mares, and other animals, running at grass, 

 have escaped, but later intelligence seldom or never fails to report their 

 sickness. So, too, at Scranton and other mining regions in Pennsyl- 

 vania the mules working underground kept well for about six days after 

 those on the surface were suffering. The majority of the reports testify 

 that animals at grass in mild weather were later in being attacked, and 

 suffered less than those in regular work and stabled. Yet some report 

 that those at pasture and away from all other horses suffered as early 

 and as severely as those in-doors. 



The percentage of horses attacked has been variously stated at from 

 80 to 99. As the reports are mostly written before the disease has quite 

 passed away, it is probable that the latter number is nearest the general 

 average. 



The fatality appears to have been from 1 to 2 per cent, on a general 

 average, though it has been considerably higher than this in some of 

 the larger cities. The highest reported Avas at Farmingdale, New York, 

 where it was claimed that 10 per cent, of the heavy horses had died. 

 This was, however, drawn from too small a number of cases to be of any 

 value as an average. 



SYSIPTOMS AND COURSE. 



Incubation, — From the analogy it bears to other fevers influenza would 

 be expected to possess a period of incubation, during which the poison 

 which had obtained access to the system should remain there apparently 

 dormant and without giving any outward sign of its presence, but really 

 undergoing a process of rapid multiplication and establishiug its hold 

 on the animal economy. The duration of such incubation has not been 

 definitely ascertained, the disease not having been transmitted by ex- 

 perimental inoculation ; but, from the observation of cases in which it 

 has appeared in a stable after the introduction of a sick animal, it is 

 supposed to extend from one to three days. 

 14 A 



