1896.] Effects of partial Thyroidectomy in Animals. 361 



Fig. 1. 



From a dog the whole of one lobe of the thyroid, including the parathyroid, was 

 removed, and also the lower five-sixths of the other lobe, leaving only the upper 

 sixth and the parathyroid. Figure shows (magnified 90 times) a section of the 

 thyroid tissue proper left; it was removed from the dog after 132 days. 



Fig. 2. 



Section of hypertrophied thyroid in a case of Graves's disease ( x 110). 



there too the secreting cells have become columnar, the walls of the 

 vesicles are similarly convoluted (see figure), and the secretion con- 

 sists only to a small extent of normal colloid, but mainly of a sub- 

 stance which does not stain readily, and appears to be more 

 watery. 



This resemblance is so close that it suggests that the cause of the 

 goitre in Graves's disease is an attempt at compensation of some 

 kind; if so it would be necessary, in order to account for the extent 

 and persistence of the change, further to suppose that the attempt at 

 compensation was unsuccessful. 



The parathyroid that is left in these experiments also enlarges. 



