Studies on the Endocrine (Hands H43 



considerably flattened. The boundary between the colloid and protoplasm 

 is less sharp. The cell-nuclei are deeply stained by hfetnatoxylin. The 

 distention of the vehicles with colloid gives a remarkably reduced appear- 

 ance to the intervt'sicular connective tissue. The colloid is faintly stained 

 by eosin. Occasionally debris of cells is to be observed niinjrled with the 

 colloid. These chanijcs become very pronounced if the thyroid feedinjj 

 is continued for a lonir time. But there are indivi(hial differences, and 



Fio. 4. — SL'ction showing adjacent portions of thyroid and parathyroid of male rat 

 fed with an addition of 2 centigr. of drj' ox-pituitarj- body (posterior lobe) to 

 the ordinary food per diem for seven days Microphotograj)ii ; magnified 200 

 diameters. Ha.'matoxylin-eosin preparation. 



Tile epitlielium cells lining the thyroid vesicles have a swollen appearance, 

 and their nuclei are irregular. The colloid within the vesicles is thin ; it is 

 stained very slightly with hsematoxylin. The parathyroid is not very ditterent 

 in ajipearance from the normal. 



in some subjects all the changes which have been described are far 

 less distinct. 



After the administration of sodium and potassium iodide, changes in 

 the appearance of the thyroid vesicles are observable which are for the 

 most part similar to those recorded as the result of thyroid feeding. 



After feeding with parathyroid, there did not appear to be much 

 difference betw^een the thyroid of the animal and one fed with thyroid 

 alone ; but, since the animal fed with parathyroid had previously been 

 subjected to thyroid feeding, it is possible that the effects of this had not 

 passed off 



Changes in Parathyroid. — It is not uncommon to find after thyroid 

 feeding, as well as after administration of sodium and potassium iodides 



