5i2 THE DISEASES OF THE HORSE 



LARYNGITIS, ROARING, WHISTLING, ETC. 



One of the most common diseases among well-bred horses of the present 

 day is the existence of some mechanical impediment to the passage of the 

 air into the lungs, causing the animal to "make a noise." The exact nature 

 of the sound has little or no practical bearing on the cause that produces it; 

 that is to say, it cannot be predicated that roaring is produced by laryngitis; 

 nor that whistling is the result of a palsy of some particular muscle, but 

 undoubtedly it may safely be asserted that all lesions of the larynx, by 

 which the shape and area of its opening (rima glottidis) are altered and 

 diminished, are sure to have a prejudicial effect upon the wind, and either to 

 produce roaring, whistling, wheezing, or trumpeting, but which would result 

 it might be difficult to say, although the precise condition of the larynx 

 were known, which it cannot be during life. Veterinary surgeons were 

 formerly puzzled by often finding on examination of a roarer's larynx 

 after death no visible organic change in the opening, and many were 

 led to imagine that this part could not be the seat of the disease. On a 

 careful dissection, however, it is found that a muscle or muscles whose 

 office it is to dilate the larynx is wasted and flabby (crico-arytenoideus 

 lateralis and thyro-aiytenoideus). The other muscles ai-e perhaps equally 

 atrophied, but as their office is to close the opening, their defects are not 

 equally injurious, and at all events are not shown by producing an unnatural 

 noise. 



The cause of this wasting is due to some defective nerve supply, and 

 careful examination and dissection shows it is degeneration of its structure 

 and interruption of the current. It is a subject which has occupied the most 

 eminent veterinarians with hitherto very little progress towards an accurate 

 knowledge of its pathology. It was hoped at one time that excision of a 

 portion of cartilage would prove a success, but experiments upon a goodly 

 number of army horses proved that the relief was only temporary, and that 

 falling in of the larynx and a still greater diminution of its calibre followed, 

 so that the operation was eai-ly abandoned. 



A MORE SUCCESSFUL OPERATION is that of tracheotomy, which consists in 

 the introduction of a metal tube into the trachea, permitting the air to be 

 breathed direct into the lungs instead of passing through the ordinary way. 

 The place usually selected is between the third and fourth rings of the trachea, 

 where the windpipe has the smallest amount of muscular covering, but 

 the plan adopted and the instrument invented by Mr. Jones, M.R.C.Y.S., 

 of Leicester, has certain advantages over the old method. This gentleman 

 inserts the tube very high up, where it can only be seen by a person looking 

 under the horse's head, and in a position where it is less likely to meet with 

 external violence. The tube is provided with a plug which can be kept in 

 it at night only, and must not be left out in swimming or the creature 

 may be drowned. The owner of a favourite hunter so operated on is 

 generally satisfied with about two seasons, and such horses find their way 

 into cabs at a nominal sum. For several reasons it will be necessary to 

 examine first of all into the several kinds of inflammation, etc., to which 

 the larynx is subject, and then to investigate as far as we may, the nature, 



