ITS CAUSES AND SYMPTOMS. 403 



Symptoms. The most striking feature is the swelling close under 

 the larynx, and towards the side of the trachea. In horses the gland 

 on either side, usually not larger than a chestnut, attains the 

 dimensions of a man's fist. It sometimes becomes as large in dogs. 

 As the gland grows in size and weight it sinks, and becomes more 

 prominent. Either one or both glands may be affected. 



As long as the size of the thyroid is not much increased, goitre 

 in animals is of little significance. In the horse, however, Massot, 

 Neyraud and Truelsen have observed difficult deglutition, and 

 dyspnoea from the swelling pressing on the trachea. This occurs 

 more often in dogs, which may be unable to lie down, on account 

 of the swelling compressing the trachea and interfering with 

 breathing. The trachea may be narrowed until it closely resembles 

 a scabbard. Zschokke found carcinomata in dogs invading the 

 trachea and oesophagus, and producing difficulty both in breathing 

 and swallowing. Johne reports the case of a dromedary calf which 

 died at birth from suffocation produced by a goitre swelling weighing 

 nearly 13 pounds. In a horse, sarcoma of the thyroid spread entirely 

 over the larynx during the space of a year and a half, and finally 

 caused death by suffocation. 



Prognosis. In animals, and especially in young dogs, goitre 

 is not simply a blemish, although some varieties occurring in horses 

 cause no inconvenience. The significance of the case depends upon 

 the size of the swelling and its rate of increase, but our knowledge 

 of the condition does not justify very sanguine expectations. 

 Extirpation entails not only the danger of excessive bleeding, but 

 also the development of peculiar symptoms described as cachexia 

 strumipriva, which are frequently seen in young dogs. Some weeks 

 after total removal of the thyroid, marked weakness appears, 

 accompanied by anaemia and wasting, from which the animals 

 finally die. These symptoms, however, can be prevented by giving 

 a daily dose of fresh thyroid gland. 



Von Eiselsberg observed the disease in lambs. Two months after 

 extirpation of the gland, the animals' growth became checked. They 

 remained much smaller, weaker, and of less weight than the control 

 animals. The anterior portion of the head was shorter, the posterior 

 portion enlarged, the abdomen distended, the testicles atrophied, the wool 

 badly developed. One of the sheep suffered from catarrhal attack of 

 the lungs, but von Eiselsberg regarded this as an accidental symptom. 

 The temperature was 1*5 to 2 degrees Cent, below normal. Von Eiselsberg 

 noted similar symptoms in a goat whose thyroid had been removed at the 

 age of six weeks. 



It was formerly believed that this gland was a secretory organ, which 

 could be dispensed with without danger to life. But Griitzner demon - 



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