24 HORSE, SWINE 'AND POULTRY DISEASES 



excited by pressing upon the larynx with the thumb and finger. The 

 larynx should be pressed from side to side and the pressure removed 

 the moment the horse commences to cough. A painful cough occurs 

 in pleurisy, also in bronchitis and bronchial pneumonia. Pain is 

 shown by the effort the animal exerts to repress the cough. The 

 cough is not painful, as a rule, in the chronic diseases of the respira- 

 tory tract. The force of the cough is considerable when it is not 

 especially painful and when the lungs are not seriously ^ involved. 

 When the lungs are so diseased that they can not be filled with a large 

 volume of air, and in heaves, the cough is weak, as it is also in weak, 

 debilitated animals. If mucus or pus is coughed out, or if the cough 

 is accompanied by a gurgling sound, it is said to be moist ; it is dry 

 when these characteristics are not present that is, when the air in 

 passing out passes over surface not loaded with secretion. 



In the examination of the chest we resort to percussion and aus- 

 cultation. Percussion is practiced with the fingers alone or with the 

 aid of a special percussion hammer and an object to strike upon 

 known as a pleximeter. If the fingers are used, the middle finger of 

 the left hand should be pressed firmly against the side of the horse 

 and should be struck with the ends of the fingers of the right hand 

 bent at a right angle so as to form a hammer. After experience in 

 this method of examination one can determine with a considerable 

 degree of accuracy whether the lung contains a normal amount of air 

 or not. If, as in pneumonia, air has been displaced by inflammatory 

 product occupying the air space, or if fluid collects in the lower part 

 of the chest, the percussion sound becomes dull. If, as in emphysema 

 or in pneumothorax, there is an excess of air in the chest cavity, the 

 percussion sound becomes abnormally loud and clear. 



Auscultation consists in the examination of the lungs with the 

 ear applied closely to the chest wall. As the air goes in and out of the 

 lungs a certain soft sound is made which can be heard distinctly, espe- 

 cially upon inspiration. This sound is intensified by anything that 

 accelerates the rate of respiration, such as exercise. This soft, rustling 

 sound is known as vesicular murmur, and wherever it is heard it 

 signifies that the lung contains air and is functionally active. The 

 vesicular murmur is weakened when the lungs are compressed by 

 fluid in the chest cavity. The vesicular murmur disappears when air 

 is excluded by the accumulation of inflammatory product, as in 

 pneumonia, and when the lungs are compressed by fluid in the chest 

 cavity. The vesicular murmur becomes rough and harsh in the early 

 stages of inflammation of the lungs, and this is often the first sign of 

 the beginning of pneumonia. 



Additional sounds are heard in the lungs in some diseased condi- 

 tions. For example, when fluid collects in the air passages and the 

 air is forced through it or is caused to pass through tubes containing 

 secretions or pus. Such sounds are of a gurgling or bubbling nature 

 and are known as mucous rales. Mucous rales are spoken of as being 

 large or small as they are distinct or indistinct, depending upon the 

 quantity of fluid that is present and the size of the tube in which this 

 sound is produced. Mucous rales occur in pneumonia after the solid- 



