DISEASES OF THE RESPIRATORY SYSTEM. 117 



ACUTE CATAERHAL LARYNGITIS. 



What is acute catarrhal laryngitis ? 



It is an acute inllammation of the mucous membrane lining 

 the larynx with products of a catarrhal inflammation, characterized 

 by fever, a cough, and difl&cult deglutition. 



What is the pathology? 



There is redness, swelling, and softening of the mucous mem- 

 brane of the larynx, which is at first dry, due to the arrest of the 

 secretion of the mucous glands; soon we find the membrane cov- 

 ered with mucus, which contains epithelial and pus-cells. 



On post mortem, there is often less redness and swelling than 

 there is during life, owing to the richness of elastic tissue. The 

 redness and swelling are due to an increased amount of blood and 

 the infiltration into the membrane. 



The inflammation runs a more or less rapid course, and the 

 parts return to the normal; in some cases it may become chronic. 

 If superficial erosions are present, there may be ecchymotic spots, 

 or even an escape of blood, due to an involvement of the capillary 

 vessels. 



In some cases it is limited to a portion of the larynx, chiefiy 

 near the epiglottis, in which case it is apt to be associated with an 

 infiammation of the fauces and pharynx. 



The danger in this form of laryngitis is due to the submucous 

 inflammation as well as to spasm of the glottis, which the infiltra- 

 tion causes. 



What is the aetiology ? 



It is caused by chillings of the skin, as when the animals have 

 long hair and sweat easily. It is often seen in the spring or fall, 

 when there is a change in the atmosphere. 



It is also caused by inhalations of irritating gases, smoke, dust, 

 etc. Continued pressure or mechanical injuries to the larynx may 

 be a cause, as a tight throat latch; it is often associated with stran- 

 gles, nasal catarrh, influenza, etc. 



What are the symptoms of acute laryngitis ? 



A chill may be present and there are well-marked febrile 

 s3rmptoms; the pulse is quickened and full, the temperature is 105° 

 to 106° F., and there is a cough present which is at first dry and 



