124 Mr. W. Edmunds. 



These observations I have repeated: eighteen experiments were 

 made in dogs ; in all it was intended to excise all the parathyroids, 

 leaving, as a rule, the thyroid proper ; but in seven it was subse- 

 quently found that one, and in one case two, of the smaller para- 

 thyroids had escaped excision ; these seven experiments were therefore 

 cases of partial parathyroidectomy or parectomy. 



Of the eleven experiments in which the whole of the parathyroids is 

 believed to have been removed, in two, one of the thyroid lobes was 

 removed at the same time ; of these two, one dog died the night after 

 operation and the other survived the operation, but died when the 

 remaining thyroid lobe was subsequently removed. 



Of the nine cases in which the parathyroids only were removed, 

 four died : one in two days, one in four days, one in seven days, and 

 one in twenty-eight days. 



The other five survived the operation, two after temporary symptoms 

 arid three without. 



Thus of the nine total parectomies, four died, two recovered after 

 symptoms, and three without. 



The five which recovered were submitted to further excision of one 

 thyroid lobe, and (if they survived this) of the other thyroid lobe. 

 Two died after removal of the first lobe, one died after removal of the 

 second lobe, and two survived even this, which amounted to total 

 thyroidectomy, but they both had temporary symptoms. 



The symptoms produced by these operations were (1) tremors, (2) a 

 slow and most unstable gait, sometimes going on to paralysis of the 

 hind limbs, and (3) emaciation and weakness. 



In two of the dogs an interesting eye symptom was noticed, viz., a 

 narrowing of the palpebral fissures with apparent recession of the eye- 

 balls. This occurred in one dog who succumbed to excision of the para- 

 thyroids only, and in one dog who survived this, but died after excision 

 of one thyroid lobe. 



In six of the eleven cases microscopic changes were found in the 

 thyroid lobes left at the excision of the parathyroids ; these changes 

 were (1) a diminution or absence of the colloid in the vesicles, (2) an 

 excessive amount of intervesicular young thyroid tissue, (3) multiplica- 

 tion of secreting cells in the thyroid vesicles, and (4) the secreting cells 

 becoming columnar. These changes are very similar to or identical 

 with those described as compensating hypertrophy of the thyroid, and 

 to those found in Graves's disease. 



In seven dogs the larger parathyroids were removed, but it was sub- 

 sequently found that one, and in one case two, of the smaller para- 

 thyroids had escaped excision, these were therefore cases of partial 

 parectorny. 



Notwithstanding the incompleteness of the excision, in one of these 

 cases the animal succumbed to the operation after seventy-two days. 



