DISEASES OP THE RESPIRATORY ORGANS. 217 



be given in the form of coniurn, hyoscyamus, belladonna, 

 and especially Dover's powder. 



Certain oils and balsams, as copaiba, balsam of Tolu, 

 etc., seem to exercise a beneficial effect. 



If suffocation threaten from swelling, tracheotomy 

 should be performed — an operation to be avoided, if possi- 

 ble, on account of all wounds about the neck of the dog 

 tending to bleed excessively. 



Should the disease become chronic, various applica- 

 tions found useful in human practice may be tried with 

 the dog, though to place a solution with any degree of cer- 

 tainty in the larynx itself is not always possible. A brush 

 with handle bent at a right angle will be most serviceable. 

 A solution of chloride of zinc in water to the extent of 

 ten to forty grains to the ounce, and then diluted one half 

 with glycerin, is excellent ; but at first great care must be 

 exercised lest glottic spasm be produced. 



Pleurisy. — The inner surface of the thoracic walls, the 

 upper aspect of the diaphragm, and the lungs themselves, 

 are covered with an elastic smooth membrane, lubricated 

 in health with a small quantity of fluid secreted by its own 

 investing cells. 



In pleurisy or inflammation of this covering it be- 

 comes dry, the friction of the opposed surfaces gives rise 

 to pain, and sometimes to a rough grating or crackling 

 sound — " friction sound" — which is diagnostic. 



Causes. — Similar to those producing other inflamma- 

 tions of the respiratory tract, but, in addition, various con- 

 ditions of the system, as rheumatism, kidney disease, blood 

 poisoning {septiccemia), etc. It is a frequent complication 

 or accompaniment of other diseases of the lungs when it is 



