RESPIRATORY APPARATUS. 115 



Expectoration. The act of coughing tends to eject 

 -masses of mucus, exudate, etc., from the bronchi, trachea, and 

 larynx. Animali, do not expectorate because that which 

 is coughed up into the throat, as soon as it reaches the phar- 

 ynx, is swallowed. Sometimes, however, a part is discharged 

 through the mouth, the lower naso-pharyngeal wall and the 

 soft palate being forced forward by the air passing out, which 

 leaves the opening into the buccal cavity free. The thus ex- 

 pectorated mass is usually mixed with mucus from the phar- 

 ynx and mouth and also with food particles. 



It is possible to collect "sputum" from horses and cattle 

 for microscopic or bacteriological purposes. The method of 

 obtaining it is to cause the animal to cough, then place a spec- 

 ulum in the mouth and reaching back with your hand as far 

 as the larynx, gather the accumulated mucus in this region. 



Several times in horses suffering from tuberculosis I 

 have thus succeeded in obtaining bronchial discharge in which 

 tubercle bacilli were found. 



VII. The Voice. 



Cattle suffering from nymphomania keep up an almost 

 ■continuous bellowing ; in advanced cases they moan loudly 

 and constantly. At the approach of death horses sometimes 

 utter a shrill neigh. 



Change in voice is of little significance in animals. 

 Commonly we observe a hoarse voice in laryngeal catarrhs. 

 This is most marked in dogs. In rabies the voice sufifers 

 change. In dogs afifected with this disease the bark is pro- 

 longed into a long, dismal howl, the voice being at the same 

 time hoarse. In horses a short, squealing tone is emitted. 



VIII. The Larynx and Trachea. 



Inspection. Enlargements in the region of the larynx 

 are as a rule not confined to this organ, but to neighboring 

 tissues as the pharynx, lymph glands, subcutis. 



