516 



Old, cold, damp, foul, unclean, and badly drained and ventilated 

 stable's aUow rapid dissemination of the disease to other horses in the 

 same stable, and act as rich reservoirs for preserving the contagion 

 which, in one of these cases, the writer knew to be retained for over 

 a year. Every few weeks during this time, in the corner of a large 

 livery stable, one or more cases of oedematous pneumonia broke out, 

 usually in one of two stalls, but sometimes several stables away. 

 When the stable was remodeled and new woodwork was placed in 

 for mangers and floors the disease disappeared. The virus is but 

 moderately volatile, and in a stable seems rather to follow the lines 

 of the walls and irregular courses than the direct currents of air and 

 the tracts of ventilation. Professor Dieckerhoff found that the con- 

 tagion of influenza was readily diffusible throughout an entire stable 

 and through any opening to other buildings, and substantiates the 

 writer's experience that it will pass through solid walls of considera- 

 ble thickness; but he also found that the contagion of (edematous 

 pneumonia is not transmissible at any great distance, nor is it very 

 diifusible in the atmosphere. A brick wall 8 feet in height served to 

 prevent the infection of other animals placed on that side of a horse 

 ill with the disease, while others placed on the opposite side and 

 separated from the focus of contagion only by open bars in the stall 

 were infected and developed the disease in its typical form. 



Symptoms.— The symptoms differ slightly from those of a frank, 

 fibrinous pneumonia, but not so much by the introduction of new 

 symptoms as by the want of or absence of the distinct evidences of 

 local lesions which are found in the latter disease. All of the pneu- 

 monias throughout the whole course of the trouble are less marked 

 and less clearly defined. 



At first the symptoms are latent; the animal gives a rare cough 

 which resembles that of a heavy horse affected with a slight chronic 

 bronchitis; it becomes somewhat dejected and dull, at times somno- 

 lent, and has a diminished appetite. This condition lasts for several 

 days. No history can be obtained of causes for symptoms of acute 

 trouble, and the absence of organic lesions to account for the general 

 condition leaves the attendant, however expert he may be, in much 

 doubt as to the nature of the trouble unless previous cases in the same 

 stable, or special tact on the part of the veterinarian, aids in foresee- 

 ing the probable termination of the slight local trouble and commenc- 

 ing adynamic changes in the organic functions of the animal. No 

 crepitant rale is heard as in fibrinous pneumonia, as in this disease 

 the local trouble commences in the neighborhood of the large air tubes 

 and not on the periphery of the lungs. During several days these 

 symptoms increase and a fever of a low type gradually develops. The 

 respiration increases to twenty-four, thirty, or thirty-six to the min- 

 ute, and a small, running, soft pulse, indicating great exhaustion ot 

 the capillaries and their surrounding tissues, attains a rhythm ot htty, 



