360 



Mr. W. Edmunds. 



[Mar. 19, 



XI. 4< Effects of partial Thyroidectomy in Animals." By 

 Walter Edmunds, F.R.C.S. Communicated by Dr. J. R. 

 Bradford, F.R.S. Received March 19, 1896. 



(From the Laboratory of the Brown Institution.) 



Gley, of Paris, has shown, in the case of dogs, that if in each of 

 the two lobes of the thyroid gland the parathyroid be separated 

 from the thyroid tissue proper, and the latter (that is to say the 

 bulk of the thyroid) be excised and the two parathyroids left, these 

 are so sufficiently able to carry on the functions of the thyroid gland 

 as to keep the dog alive and apparently in good health : further, 

 if the two parathyroids are subsequently excised, the dog will die 

 with symptoms of athyroidea. It is not, however, even necessary to 

 leave both the parathyroids, for in two experiments I have found the 

 dog live when only one parathyroid was left, the animal dying only 

 when subsequently the parathyroid was excised. 



Gley also found that if partial thyroidectomy was so performed as 

 to remove both the parathyroids, it was necessary, in order that the 

 dog might live, to leave considerably more than half of one lobe of 

 thyroid tissue proper ; my own results agree with this. 



The changes which ensue in the portions of thyroid tissue and 

 parathyroids left in situ in these experiments are of interest. 



The portion of thyroid hypertrophies, obviously, as a rule, and 

 microscopically, there is found — 



(1.) An enlargement of the vesicles ; 



(2.) The secreting cells lining the vesicles become columnar, as 

 described by Hurthle ; 



(3.) The inner wall of the vesicles becomes convoluted and raised 

 into minute papillae (as shown in accompanying figure) ; the effect of 

 this is to greatly increase the area of the inner surface of the vesicle, 

 and thus allow of a much greater number of secreting cells being 

 arranged one deep on the wall of the vesicle : indeed, very possibly, 

 the cause of the alteration is the demand for more thyroid secretion 

 leading to an increase in the number of secreting cells which would 

 require and make an increase of area of basement membrane ; a 

 simple enlargement of the vesicle, without any papillae, would no 

 doubt effect the same, but the mutual pressure of the vesicles and 

 that of the connective tissue between them would prevent this. 



(4.) The secretion in the vesicles is altered ; there is compara- 

 tively little ordinary colloid, but, instead, a substance which stains 

 much less readily and appears to be of a more watery consistence. 



It is worthy of note that these appearances are almost identical 

 with those found in the enlarged goitre in cases of Graves's disease : 



