CHAPTER IV 

 THE THYROID AND PARATHYROIDS {continued) 



The Effects of Surgical Removal and of Atrophy or 

 Degeneration of the Thyroid: Hypothyroidism 



Thyroidectomy. — Schiff, who had previously (1856) performed the opera- 

 tion in various animals with incomplete results, was led in 1884 to again 

 investigate the effect of thyroidectomy in animals : he was also the first to 

 attempt to combat the resulting symptoms by implantation of thyroid from an 

 animal of the same species. SchifFs extirpations probably in most instances, 

 as the symptoms he records show, included the parathyroids. Gley drew 

 attention to the importance of leaving at least two of these in order 

 to study the effects of thyroidectomy alone. Subsequent observations on 

 the subject are numerous, although some are contradictory. This is due 

 mainly to the fact that differences are found with animals of different 

 species, and that age introduces a material factor into the result; young 

 animals being much more susceptible to thyroidectomy than adults, as they 

 are also to parathyroidectomy. 



When positive results are seen in adult animals they take the form of 

 thickening and dryness of the integument, with a tendency to loss of hair. 

 Adiposity may supervene later, although there is at first usually some 1/ 

 waiting. The muscles lose tone and are weaker than in the normal animal. 

 Regeneration of tissues is retarded. Anaemia is usually present. The body 

 temperature is low ; the power of heat regulation by means of the skin is 

 diminished (Lorraine Smith). The sexual functions are interfered with. 

 The limit of assimilation of carbohydrates is raised. The nervous system is 

 markedly affected, dullness and apathy being prominent symptoms. Many 

 nerve-cells, especially those of the cerebral cortex, exhibit a shrunken 

 appearance and present a strong contrast with those of the normal animal. 

 A ruyxoedematous condition of the integument was described in monkeys 

 by Horsley, Murray, and Edwards, but others (H. Munk, Kishi, Vincent 

 and Jolly, Halpenny and Gunn) have not seen this. 



Similar symptoms are observed in cases of spontaneous atrophy, or 

 degeneration of the gland in children (fig. 18, A). There is arrest of growth, 

 especially of the skeleton, the cartilage bones long remaining incompletely 

 ossified ; development of the generative organs is much delayed ; the integu- 

 ment is swollen ; the surface of the skin is dry ; the hair tends to fall out 

 and becomes thin ; the face is pale and puffy ; the abdomen swollen ; the 

 nose depressed ; the hands and feet are podgy. The f ontanelles of the skull 



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