DISEASES OF CATTLE 19 



in health, becoming excessively irritant and yielding evidence of 

 chemical and other alterations in the character of the secretion. 



Cough. Cough depends upon a reflex nervous action, and may 

 be primary when the irritation exists in the lungs or air passages, 

 or secondary when due to irritation of the stomach, intestines, or 

 other parts having nervous communications with the respiratory 

 apparatus. A cough is said to be dry, moist, harsh, hollow, difficult, 

 paroxysmal, suppressed, sympathetic, etc., according to its char- 

 acter. Cough is a very important symptom, often being diagnostic 

 in diseases of the respiratory organs; but this is a subject which 

 can be more satisfactorily treated in connection with special diseases. 



Respiration. In making an examination of an animal observe 

 the depth, frequency, quickness, facility, and the nature of the 

 respiratory movements. They may be quick or slow, frequent or 

 infrequent, deep or imperfect, labored, unequal, irregular, etc., each 

 of which has its significance to the educated and experienced veteri- 

 narian. Sleep, rumination, pregnancy in cows, etc., modify the 

 respiratory movements even in health. Respiration consists of two 

 acts inspiration and expiration. The function of respiration is 

 to take in oxygen from the atmospheric air, which is essential for 

 the maintenance of life, and to exhale the deleterious gas known as 

 carbon dioxid. 



The frequency of the respiratory movements is determined by 

 observing the motions of the nostrils or of the flanks. The normal 

 rate of respiration for a healthy animal of the bovine species is 

 from fifteen to eighteen times per minute. The extent of the res- 

 piratory system renders it liable to become affected by contiguity 

 to many parts, and its nervous connections are very important. 



Rapid, irregular, or difficult breathing is known as dyspnea, 

 and the animal in all such cases has difficulty in obtaining the 

 amount of oxygen that it requires. Among the conditions that give 

 rise to dyspnea may be mentioned restricted area of active lung tis- 

 sue, due to filling of portions of the lungs with inflammatory ex- 

 udate, as in pneumonia; painful movements of the chest, as in rheu- 

 matism or pleurisy; fluid in the chest cavity, as in hydrothorax; 

 adhesions between the lungs and chest walls; compression of the 

 lungs or loss of elasticity; excess of carbon dioxide in the blood; 

 weakness of the respiratory passages ; tumors of the nose and paraly- 

 sis of the throat; swellings of the throat; foreign bodies and con- 

 striction of the air passages leading to the lungs ; fevers, etc. 



As already alluded to, it is only the careful and constant ex- 

 amination of animals in health that will enable one properly to ap- 

 preciate abnormal conditions. One must become familiar with the 

 frequency and character of the pulse and of the respirations, must 

 know the temperature of the animal in health, before changes in 

 abnormal conditions can be properly appreciated. 



Temperature. The temperature should be taken in all cases 

 of sickness. Experienced practitioners can approximate the patient's 

 temperature with remarkable accuracy, but I would strongly recom- 

 mend the use of the self-registering clinical thermometer, which is 



