104 



DADD'S VETERINARY MEDICINE AND SURGER7. 



to be about eight years of age, the tumors acquire such magni- 

 tude that the}- press on the vocal organs, so as to decrease the 

 caliber of the larynx, and thus the animal becomes a "roarer." 

 Judging from what we know of the disease in the human subject, 

 the glands, while undergoing enlargement, do not occasion much 

 pain. The danger arises from mechanical causes, and the death 

 of the subject, if it occur, is due to asphyxia, or suffocation. 

 Among horses there arc very few fatal cases on record. The 

 reverse is the case as regards sheep. When these glands are 

 much enlarged, and the animal is near or past the adult age, it 

 is very unsafe to attempt their removal by means of the knife; 

 for at this stage they are highly vascular, and the arteries which 

 run into them are much enlarged. The operation has been suo- 



frKOWING THK TTTMOB OF BBOHCHOCELE IN THE BEQ10H OF THB THIOi*. 



usssfully performed on lambs, but it must be done when they ai« 

 quite young, and the artery must be secured before the gland is 

 extirpated, or the animal will bleed to death in a few seconds. It 

 is well known among the members of the profession that the dis- 

 ease is incurable; and the same remarks apply to all hereditary 

 diseases, yet the growth of the glands may be retarded by means 

 of local and constitutional treatment. 



The thyroid glands are two ovoid bodies, varying in size from 

 a filbert to an egg, located in the region of the thyroid cartilage 

 (throat), one on each side of the trachea (windpipe). Their at- 

 tachments are cellular. When cut into, they exhibit a porus tex- 

 ture, highly vascular, well supplied with blood-vessels. Very 

 little is known of their physiology. They are called vascular 



