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Scientific Proceedings (131) 



twenty-four hours in acute tetany, another succumbed in two 

 days and the remaining fifteen lived for months. Some were 

 killed for want of space, and several that were allowed to live 

 showed the chronic changes which follow thyroidectomy. 



In January, 1921, the same operation — complete thyropara- 

 thyroidectomy — was performed on twenty-four rabbits, most of 

 them adults. Five died in tetany one day after the operation — 

 tracings of the muscular contractions were obtained from two, — 

 four died on the second day, six had succumbed between the 

 second and the tenth days, one on the eighteenth day, and the 

 remaining eight lived until they were killed months afterwards. 

 In this second series the proportion showing acute symptoms was 

 much greater than in the first. 



Accessory parathyroid tissue is said to be present in the rabbit 

 fairly frequently. This is small in amount, no doubt, but the 

 first explanation one thinks of to account for the survivals is 

 that some of this tissue has been inadvertently left behind. In 

 the light of work recently reported by Dragstedt and by Luck- 

 hardt, however, another explanation is suggested. These ob- 

 servers found that in the dog the symptoms could be controlled 

 by the diet. The toxic substances leading to tetany, they believe, 

 are produced chiefly in the gastro-intestinal tract, arising through 

 the activity of the proteolytic group of intestinal bacteria, and 

 are probably, for the most part protein split products of the 

 nature of amines. A diet rich in proteins is contraindicated 

 therefore, and putrefactive changes in the intestine are to be 

 prevented. 



The diet of the first group of rabbits consisted almost entirely 

 of green clover, while in the case of the second group it was 

 mainly oats and cracked corn, although small quantities of cab- 

 bage were included. This dry feed would probably be richer in 

 protein and would also tend to induce constipation and so putre- 

 factive changes. This may conceivably account for the high 

 proportion of acute (parathyroid) cases in the second or winter- 

 fed group. 



