485 



yellowish coloration of the mucous membranes, and swelling of the 

 under surface of the belly and legs, but in pneumonia we have the his- 

 tory of the diflliculty of breathing and an acute fever of a sthenic type 

 from the outset, and the other symptoms do not occur for several days; 

 while in influenza we have the history of characteristic symjitoms for 

 several days before the raj^id breathing and difSculty of respiration in- 

 dicate the appearance of the complication. Without the history it is 

 frequently difficult to diagnose a case of influenza of several days' 

 standing complicated hj pneumonia from a case of severe pneumonia 

 of five to six days' standing, but from a prognostic point of view it is 

 immaterial, as the treatment of both are identical. 



Prognosis. — Influenza is an excessively serious disease for many rea- 

 sons. We find the majority of horses susceptible to this virus when 

 exposed to it. It is fatal to a large number of animals even with the 

 best treatment, and is especially fatal to the young and to those ani- 

 mals which are more valuable from their fine breeding, as the disease 

 occurs in a more serious form in well-bred animals than it does in the 

 lymphatic and more common ones. It is more severe than the other 

 epizootic diseases, as its contagiousness is much greater than in the 

 others. 



The fatal issue of influenza varies in different epizootics ; where the 

 disease is occurring only in scattered cases through a large town or 

 country locality, and in some epizootics, the majority of the cases run a 

 mild form without complications; at other times, where the disease 

 occurs in enzootic and epizootic form, we find over 50 j^er cent, of the 

 cases complicated by disease of the lungs ; in others a large number of 

 cases are complicated by trouble of the intestines. 



Alterations. — The alteration of influenza occurs in the blood, and con- 

 sists of a rapid destruction of the red blood corpuscles, which are the 

 carriers of oxygen from the lungs to all jiarts of the body. The animal 

 is always fonnd emaciated. The tissues throughout the body are found 

 stained, and of a more or less yellowish hue, due to the disintegrated 

 blood corpuscles which were at first the cause of the characterized dis- 

 coloration of the mucous membranes in the living animal. There is 

 ;always found a congested condition of all the organs, muscles, and in- 

 terstitial tissues of the body. The coverings of the brain and spinal 

 cord partake in the congested and discolored condition of the rest of the 

 tissues. 



Other alterations are dependent entirely upon the complications. If 

 the lungs have been affected, we find effusions identical in their intimate 

 nature with those of simple pneumonia, but they differ somewhat in 

 their general appearance in not being so circumscribed in their area of 

 invasion. Complication of the intestines offers the red, puffy, swelling 

 or coug^ted appearance which we have in an ordinary enteritis, with 

 peeling from the surface of the membranes of the intestinal tube. The 

 alterations of meningitis and lamiuitis are identical with those of 

 sporadic cases of founder and inflammation of the brain. 



