4 



Scientific Proceedings. 



plete operation of thyro-parathyroidectomy performed on them 

 and no noticeable symptoms have followed. 



In the sheep therefore it would appear that both the thyroid 

 and parathyroid glands are much more important organs in the 

 young than in the adult animal, and consequently that they be- 

 come functionally less active as age advances. 



In relation to the influence of the parathyroids on calcium 

 metabolism it is interesting to note that the two young lambs 

 which showed acute parathyroid tetany were fed almost entirely 

 on milk, rich in calcium salts, while the three which had the 

 external parathyroids removed when they were about fourteen 

 months old, and the other two para thyroidectomized adults, lived 

 on a purely herbivorous diet in which potassium salts predominate. 

 It may be, however, that in the young animal, where bone is being 

 rapidly formed, the ratio between the demand for calcium and the 

 supply is even greater than in the adult, although in the latter a 

 far smaller quantity is being ingested. 



In the case of the adult sheep the results of thyro-parathyroi- 

 dectomy are in agreement with those of MacCallum 1 who from a 

 similar operation found that "Practically no effect whatever was 

 produced in these five sheep, although in at least three of them 

 ample time elapsed for the development of symptoms." The 

 other two died early of pneumonia, due probably to the administra- 

 tion of ether. 



3 (612) 



Peculiarity in the mode of entrance of the optic nerve into the 

 eyeball in some rodents. 



By J. A. BADERTSCHER. 



[ From the Physiological Laboratory, Medical College, Cornell 

 University, Ithaca, N. Y.\ 



In the majority of animals the optic nerve enters the eyeball 

 as a round compact bundle of nerve fibers and the optic disc is 

 circular in outline or nearly so. While removing the eyes from 

 the woodchuck and prairie dog for histological material, I observed 

 that here there was an exception to the general rule in that the 



1 MacCallum, Johns Hopkins Hosp. Bull., 1907, xviii, p. 335. 



