348 ENZOOTIC AND EPIZOOTIC DISEASES. 



1788. Influenza was very severe in New York, and caused 

 great mortality amongst the horses of Maryland. During the 

 present century the disease has raged with varying degrees of 

 virulence in 1849-50, 1863-4; and the last outbreaks we have 

 to record are — 



Influenza in Britain in 1871-72. — This outbreak was mostly 

 confined to the English metropolis ; it was of a severe but not 

 fatal type; in 1891-92 it was general all over Great Britain. 



The American Horse Disease, 1872-73. — This disease broke out 

 in Toronto, Canada, on October 1st, 1872. In nine days it had 

 attacked nearly all the horses in the city, and carriages could 

 not be had for any price. On October 18th it had reached Mont- 

 real, and was prevalent throughout Canada. On 14th October 

 it had reached Buffalo ; 17th, Rochester ; 22d, Boston, New York, 

 Brooklyn, and Jersey City ; 27th, Philadelphia ; 28th, Washing- 

 ton. It made its appearance in Nova Scotia on October 13th. 



Mr. James Law warmly advocates the contagious origin of 

 this epizootic. Mr. Greene, M.R.C.V.S., St. John's, N.B., records 

 the following important fact : — " I was always under the impres- 

 sion that influenza was both contagious and infectious till the 

 late outbreak ; since then I have altered my views with regard to 

 the contagion and infection of that disease. One among several 

 facts which I could mention will bear me out in this question. 



"During the month of July 1872 a horse had been put to 

 grass on Partridge Island, in the Bay of Fundy. This island is 

 three miles distant from this city. No other horse had been 

 near the island from the date of his landing up to the time of 

 the outbreak in St. John's, N.B., and on the 15th or 16th of 

 October, which was only two or three days after the first case 

 was reported in this city, the horse on the island was affected 

 with the most violent form of the epizootic. 



"Would not the morbific matter have become diluted to 

 such an extent (after travelling three miles) as to be inert ? " — 

 ( Veterinarian, April 1873.) 



ETIOLOGY. 



The microbe cause of influenza is not determined. The 

 disease may occur spontaneously in various places, but its first 

 source of origin cannot be indicated. It does not depend upon 

 any known condition of the atmosphere, nor upon soil, seasons, 

 or temperature. It prevails on every soil and geological for- 



