THE PARS BUCCALIS OF THE HYPOPHYSIS 95 



the normal or thyroidectomized tadpole. On the other hand, 

 the cortical adrenal tissue of the thyroidectomized tadpole 

 exceeded by twice that of the normal. Although the thyroid- 

 less animal is somewhat larger than the normal (11 mm.), yet 

 the discrepancy in the size of the adrenals is out of proportion 

 to the difference in the size of the specimens, and it thus seems 

 certain that the cortical tissue is hypertrophied in the thjrroid- 

 less larva as compared to the normal. 



Changes as striking but of a different nature are evident 

 between the adrenal medulla of a normal or thyroidectomized 

 tadpole and a hypophysectomized tadpole. In the normally 

 pigmented larva the medullary cells present a diverse appear- 

 ance, since certain cells are deeply stained and the cytoplasm 

 limited by a definite cell membrane, while the opposite extreme 

 is seen in certain other cells whose cytoplasm is reticular or even 

 vacuolated and but slightly tinged by the dye, the cell membrane 

 not being distinguishable (fig. 40). Between these two extremes 

 all gradations can be found, a condition suggestive of the various 

 secretory. states exhibited by the mammalian chromaffin tissue. 

 In the albino, on the other hand, the cells are of one type; their 

 cell boundaries are distinct and their cytoplasm moderately and 

 uniformly stained (fig. 41). Moreover, the cells are uniformly 

 larger than those either of the normal or thyroidectomized tad- 

 pole as shown by table 8. 



Not only are the chromaffin cells larger in the albino, but 

 their relation to each other and to the surrounding tissue is 

 pecuHar to these animals. They closely approximate each other 

 and the adjacent cortical tissue, spaces between or around them 

 being seldom evident. In the normal or thyroidectomized tad- 

 pole, on the other hand, an interval frequently separates these 

 cells from each other and from the cortical tissue. This con- 

 dition, which simulates shrinkage, was at first believed to be 

 an artifact. Its constant occurrence in the normal and absence 

 in the albino with identical technique suggests two possible 

 causative factors. Either these spaces exist during life or the 

 physical constitution of the cells of the normal and thyroidless 

 larvae is such that shrinkage inevitably occurs during the manipu- 



