500 INFLUENZA 



susceptible and a few cases are reported of its being transmit- 

 ted to man and to dogs. It appears sometimes in sporadic 

 form and often in epizootics. 



Influenza is a generic term employed to designate a large 

 variety of symptoms. A somewhat careful analysis of its 

 manifestations suggests that possibly it includes a number of 

 etiologically distinct diseases, i. e. , morbid conditions brought 

 about by different causative factors. The term has long been 

 employed to designate a considerable variety of equine epizo- 

 otics, the independence of which could not be established. 

 The disease, as it is seen in the horse, suggests further that 

 possibly it is in its beginning a general affection because of 

 the early rise of temperature and that later in its course it 

 becomes, to a limited extent, localized. At present influenza 

 is restricted to groups of symptoms and lesions in the horse 

 that are not very unlike those of /a grippe in man. Its 

 symptoms, lesions and sequelae warrant such a view at least 

 for a working hypothesis. As it is not usually fatal, little 

 progress seems to be made in acquiring knowledge concerning 

 the nature of its morbid anatomy. There is much need for 

 careful investigation of this very common malady. 



§ 385. History. According to the writings of Falke, 

 influenza was recognized in very early times. There is evi- 

 dence that it was known in the fourth and fifth centuries. It 

 was described by Low in 1729 in an equine epizootic which 

 had spread over Southern Europe. It is also stated that cases 

 of its having been transmitted to man had occurred. Gibson 

 observed it in 1872 in London and in different districts of 

 England. It raged in epizootics in 1760, 1776 and 1803. The 

 disease was widely disseminated during the last century. The 

 more important epizootics are reported in the years from 18 13 

 to 1815, 1825 to 1827, 1836 to 1840, 1846, 1851, 1853, 1862, 

 1870, 1873, 1881 to 1883, and 1890. Ank^r, who described 

 influenza in Switzerland in 1826, laid stress on its contagious 

 nature and stated that in his opinion "a volatile infectious 

 matter was the cause." 



Influenza spread as an epizootic in 1872 to 1873 over the 



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