History. 171 



membranes or by severe inflammation of the lungs and pleura. 

 Accordingly two forms of the disease may be distinguished, 

 namely: the catarrhal influenza, and the pectoral influenza. 



History. The term "influenza," taken from the Italian nomencla- 

 ture of human medicine (in Italian identical with " contagio "=infec- 

 tion), has been used since the beginning of the last century for all 

 acute febrile affections of horses which spread rapidly and have a 

 pronounced miasmatic, or miasmatic-contagious character. Even in 

 the middle of the century various diseases have been collected under 

 this term, and among others the petechial fever has also been con- 

 sidered in this group. Later Falke (1862) applied the term "Influenza" 

 only to the febrile catarrhal affections of the mucous membranes, while 

 to the cases in which the inflammation extended to the internal organs, 

 especially to the respiratory apparatus, he applied the name of 

 "Typhus." At the same time he considered the two forms to be 

 different in their etiological nature. 



Similar to this was the conception of Dieckerhoff, only that he 

 designated the first form as "horse distemper," and the latter as 

 "contagious pleuro-pneumonia. " At the same time he separated from 

 these, as independent affections, the "Skalma" under which he col- 

 lected those cases in which a moderate fever, a diffuse infectious 

 bronchitis, with a subacute course, without an affection of the con- 

 junctiva, or edematous infiltration of the subcutaneous connective tis- 

 sues, were the characteristic indications. Further, he also considered 

 "infectious laryngitis," "infectious pharyngitis," and "endemic 

 cough" as independent diseases. Other authors have not recognized 

 these four different forms of disease, otherwise, however, the majority 

 of German authors, as well as many French writers, have accepted the 

 classification of Falke and Dieckerhoff. 



As a matter of fact, even at the present time there are no experi- 

 mental proofs which would convincingly establish either the identity, 

 or the difference of the two diseases. Purely practical experiences, 

 however, speak rather for their close relationship. It has frequently 

 been observed in outbreaks in large stables, that while some of the 

 animals become affected with catarrhal manifestations, often with 

 serous inflammation of the tendons, in others again, severe symptoms 

 of pleuro-pneumonia develop, the characteristic affection of the eyes 

 being frequently present in both forms of the disease. As a result 

 of these observations the relation of these forms appears evident, 

 particularly as the etiological studies of their nature, b}^ which the 

 possible difference of the two forms of the disease could be established, 

 have not yet been completed. In spite of the marked differences of 

 these two forms, in which, however, transitory forms are frequently 

 observed, it appears advisable to follow the view of Siedamgrotzsky, and 

 treat the disease as two different manifestations of the same affection; 

 namely, catarrhal influenza and pectoral influenza. 



Influenza has been known from earliest times under various names 

 (Febris nervosa, F. maligna. Typhus, etc.), and its infectious nature 

 has been recognized since the second half of last century. Schiitz 

 (1887) undertook extensive bacteriological experiments to establish the 

 nature of the disease, and indicated a diplococcus as the causative 

 factor of the disease. Hell, Foth and more recently Lignieres, however, 

 proved that this bacterium is really a streptococcus, and is at least 

 closely related to the streptococcus of strangles. On the other hand, 



