430 CHARLES R. STOCKARD AND E. M. VICARI 



terrier thyroid is harder after fixation than in the other 

 bulldog types. This is difficult to explain. 



Again we find in the Boston terrier abundant extrafollicular 

 tissue, and at times extrafollieular colloid. The parafollicular 

 cells are more abundant and occur in larger masses in this 

 thyroid than in any other breed we have examined. These 

 cells are most clearly shown in the thyroid of 76 9 (pi. 85). 

 The parafollicular cells are epithelial in type, with large, 

 lightly staining bodies, and not only occur between follicles 

 but are occasionally present within the follicular epithelium, 

 as may be seen by a careful examination of several of the 

 follicles in the right half of the photomicrograph of the section 

 from 76 9 . 



Figures 3 and 4 in plate 82 are sections of the German 

 shepherd and St. Bernard thyroids. The histologic pictures 

 of these two sections are closely the same. Both have large, 

 well distended follicles filled with colloid of only medium 

 hardness, the periphery of w r hich is encircled by secretion 

 droplets, although the follicular epithelium is not high and 

 the glands are only moderately active. The extrafollieular 

 tissue is very sparse and contains extremely few epithelial 

 cells. All these features tend towards an extremely different 

 condition from that illustrated by the thyroid sections from 

 the Pekingese and the Boston terrier. 



The histologic patterns of the thyroids from all German 

 shepherd dogs are not exactly the same as that in plate 82, 

 taken from 118 9 . For comparison, sections of thyroids from 

 two other German shepherd dogs, 111 9 and 1404 $ , are 

 illustrated in plate 83 (figs. 2 and 4). These were chosen 



PLATE 82 



EXPLANATION OF FIGURES 



Comparison of thyroid sections from two short-muzzled breeds (the Pekingese 

 and Boston terrier) and two long-muzzled breeds (the German shepherd and St. 

 Bernard). 



1 Pekingese 77 $. 



2 Boston terrier 536 $. 



3 German shepherd 118$. 



4 St. Bernard 326$. 



