64 INTERNAL SECRETION 



hard, smooth, white plates which, under the microscope, showed 

 either calcification or fatty degeneration. The testicles were very 

 small. 



In goats, operated on three weeks after birth, the same author 

 was able to observe a difference in growth in comparison with 

 the control animal as early as one month after operation. At the 

 end of four months, the thyroidectomized goat was half the weight 

 of the control animal. In addition to shortening of the bones 

 of the extremities, there was marked shortening of the frontal 

 part of the head, the occipital part appearing exaggerated by 

 comparison. There were also remarkable changes in the growth 

 of the hair. The thyroidectomized sheep had poor fleece and 

 the fur of the young rabbits was scanty, but in the young goats 

 there was a conspicuous increase in the growth of the hair, and the 

 long hairs could be pulled out in handfuls. The horns, however, 

 of both sheep and goats, were equally stunted in growth. There 

 was also meteoristic swelling of the abdomen, reduction of 

 temperature, and arrested development of the sexual glands. 

 Both the general apathy and the atheromatous degeneration of 

 the aorta were very marked in goats. Pick and Pineles found 

 pronounced sclerotic changes in the aorta and enlargement of the 

 suprarenals of two goats, from which the thyroid had been 

 removed at the age of 6-10 weeks, one of which had been treated 

 with iodothyrin. In a pig which had been thyroidectomized at the 

 age of 4 weeks, v. Eiselsberg found that there was marked 

 arrestation of growth unaccompanied, however, by apathetic 

 idiocy, the animal being as lively as normal animals. 



In pigs, which had been thyroidectomized at the age of a 

 few weeks, Moussu saw a condition several weeks later, which 

 closely resembled myxoedema. There was swelling of the 

 abdomen and formation of infiltrated cutaneous folds; the skin 

 became bald in places and, in others, was covered with remarkably 

 long and thick bristles; there was also arrestation of growth. 



The infantilism, the imperfect activity of the sexual glands 

 and the general torpor, are very apparent after thyroidectomy in 

 hens. Lanz found that such birds lay very few eggs and. that 

 these are abnormally small and covered with a very thin shell. 

 The laying capacity may be increased by feeding with thyroid 

 gland. 



.In those species where the parathyroids are in close 

 anatomical relationship with the thyroid, and where extirpation 

 of the latter necessarily included the removal of the former, the 

 operation was invariably followed by acute symptoms of sup- 

 pression. The violent and fatal tetany in carnivora was believed 

 to result from suppression of the thyroid function. After the 

 discovery of the parathyroid origin of tetany, I set myself to work 

 to produce the same clinical picture in dogs as that presented by 

 the herbivora after removal of the thyroid. I was especially 

 anxious to reproduce the arrestation of growth in young animals. 



