254 Veterinary Medicine. 



months, from October to April inclusive, 146 cases=20.85 per 

 month, and in the five months, from May to September inclu- 

 sive, 62 cases=i2.4 per month. 



Excititig Causes. Nearly all the above causes when acting with 

 unusual force may become direct factors in causation. The 

 effect of a sudden and extreme chill is especially to be feared. 

 Even in cases that are unquestionably due to a microbe as the 

 essential cause, the nervous disorder manifested in the chill, and 

 the clogging of the pulmonary circulation in connection with the 

 retrocession of blood from the surface of the body furnishes the 

 opportunity for the colonization of the germ. The average horse 

 at pasture will stand with impunity cold storms of rain, snow, and 

 sleet, and transitions from a warm noonday sun to a cold night, 

 wind and dew and even frost, but under other conditions of the 

 system, with the fatigue and fret and sudden changes of food and 

 regimen attendant on domestication, or with any derangement of 

 an important bodily function the chill is often the manifest occa- 

 sion of disturbance of the balance of health, and the supervention 

 of pneumonia. Fatigue, a system charged with leucomaines, 

 and a free perspiration, which is suddenly checked by exposure, 

 at rest, to a cold rain or snow, to a draught between door 

 and window to immersion in the cold waters of a river, or 

 to sponging with cold water is quite liable to cause pneumonia. 

 An unduly heavy winter coat as an individual peculiarity or deter- 

 mined by a cold environment in autumn often predisposes strongly 

 to such dangerous chills, by the frequency and profuseness of 

 the perspirations and general relaxation of the system. Clipping 

 of such subjects is a true hygienic measure though it entails the 

 need of extra care in blanketing. Again in the animal that has 

 already suffered from disease of the respiratory organs these 

 chills are more dangerous factors. 



Direct irritation by inhalation of smoke and other products 

 of combustion ; or acrid or irritant gases or dust ; by the drawing 

 of food by aspiration into the lungs (as in paralysis of the larynx 

 or pharynx, choking, cough, apoplexy, vomiting, etc. ) ; by pour- 

 ing irritant or insoluble drugs (oil, lard) through the nose; by 

 the pressure of neoplasms (actininoycosis, tubercle, glanders, 

 cancer) ; or by the presence of parasites (strongyles, distomata, 

 echinococci, linguatulas. 



