INFECTIOUS DISEASES. 519 



which iudicates the importance of nmninj? the hand daily over 

 the hoofs to detect any sudden ele\ati()n of temperature on theii* 

 surface. 



The diafjnosis of hrain trouble is based upon tlie excessive violence 

 which occuis in the course of the disease, for durin<»; the intei'vening 

 period or coma there is no means of determinin«^ that it is ilue to this 

 complication. Severe cases of influenza may simulate anthrax in the 

 horse. In both we have stupor, the intense coloiation of the mucous 

 membranes of the eyes, anil a cei'tain amount of swelling of the legs 

 and under surface of the belly. The diagnosis here can be made 

 only by microscopic examination of the bltuxl. In sti'angles, e(|uino 

 \ariola, and scalma we have an intens<.'ly red, rosy coloration of the 

 mucous meml>ranes, full, tense pulse, and although in these diseases 

 we may have dei)re^sion, we do not have the stupor and coma ex- 

 cept in severe cases which have lasted for several days. In influenza 

 we have no evidence of the formation of pus on the mucous mem- 

 branes as in the other diseases, except sometimes in the conjunctiva'. 



In severe pneumonia (lung fever) we may fnid ])rofound coma, 

 dark-yellowish coloration of the mucous membranes, and swelling of 

 the under surface t)f the belly and legs; but in pneumonia we have the 

 history of the dilliculty of breathing and an acute fever of a sthenic 

 type from the outset, and the other symptoms do not occur for sev- 

 eral days, while in influenza we have the history of characteristic 

 symjitoms for several da3's before the rapid breathing and dilliculty 

 of respiration indicate the appearance of the complication. Without 

 the history it is freipiently difhcult to diagnose a case of influenza of 

 several days' standing, complicated by pneumonia, from a case of 

 severe pneumonia of five or six days' standing, but fi"om a prognostic 

 j)oint of view it is inunaterial, as the treatment of both are identical. 

 The fact that other horses in the same stable or neighborhood have 

 influenza may aid in the diagnosis. 



Vrofjiwxh. — Influenza is a serious disease chielly on account of its 

 numerous complications. Uncomplicated influenza is a compara- 

 tively simple malady, and is fatjil in but 1 to 5 per cent of all cases. 

 In some outbreaks, however, complications of one kind or another 

 preponderate; in such instances the rate of mortality is much in- 

 creased. 



AlteratUnm. — The chief alteration of influenza (K'curs in the diges- 

 tive tract, and ctmsists in hyperemia, infiltration, and swelling of the 

 mucous membrane, and especially of the Peyer's [)atches near the 

 ileocecal valve. The tissues throughout the Ixxly are fouml stained, 

 and of a more or less yellowish hue. There is always foimd a con- 

 gested condition of all the organs, muscles, and interstitial ti.ssues of 

 the l»ody. The coverings of the brain and spinal cord partake in 

 the congested and discolored condition of the rest of the tissues. 



