INFECTIOUS DISEASES. 515 



valescence; or, in an unfortunately large number of cases, the course 

 of the disease is complicated by local inflammatory troubles, whose 

 gravity is greater in influenza than it is when they occur as sporadic 

 diseases. 



G orrvplications. — ^The complications are congestions, followed by 

 inflammatory phenomena in the various organs of the body, but they 

 are most commonly located in the intestines, lungs, brain, or vascular 

 laminae of the feet. Atmospheric influence or other surrounding 

 influences of unknown quality seem to be an important factor in the 

 determination of the local lesions. At certain seasons of the year, 

 and in certain epizootics, we find 40 and 50 per cent or even a greater 

 percentage of the cases rendered more serious by complication of the 

 intestines ; at other seasons of the year, or in other epizootics, we find 

 the same percentage of cases complicated by inflammation of the 

 lungs, while at the same time a small percentage of them are com- 

 plicated by troubles of the other organs; inflammatory changes of 

 the brain, of the laminae, more rarely commence in epizootic form, 

 but are to be foimd in a certain small percentage of cases in all 

 epizootics. 



Exciting causes are important factors in complicating individual 

 cases of influenza, or in localizing special lesions, during either enzo- 

 otics or epizootics. These exciting or- determining causes act much 

 as they would in sporadic inflammatory diseases, but in this case we 

 find the animal much more susceptible and predisposed to be acted 

 upon than ordinary healthy animals. With a temperature already 

 elevated, with the heart's action driving the blood in increased 

 quantity into the distended blood vessels, which become dilated and 

 lose their contractility, with a congestion of all the vascular organs 

 already established, it takes but little additional irritation to carry 

 the congestion one step further and produce inflammation. 



Complication of the intestines. — When any cause acts as an irri- 

 tant to the intestinal tract during the course of this specific fever it 

 may produce inflammation of the organs belonging to it. . This cause 

 may be constipation, which can find relief only in a congestion which 

 offers to increase the function of the glands and relieve the inertia 

 caused by a temporary cessation of activity; or irritant medicines, 

 especially any increased use of antimony, turpentine, or the more 

 active remedies; the taking of indigestible feed, or of feed in too 

 great quantities, or that has been altered in any way by fungus or 

 other injurious alterations ; the swallowing of too cold water ; or any 

 other irritant may cause congestion. This complication is ushered 

 in by colics. The animal paws with the fore feet and evinces a great 

 sensibility of the belly ; it looks with the head from side to side, and 

 may lie down and get up, not with violence, but with' care for itself, 

 perfectly protecting the surface of the belly from any violence. At 



