436 CHARLES R. STOCKARD AND E. M. VICARI 



jerky and quick-moving, dancing about as it runs. Many 

 specimens of this breed also show pronounced exophthalmos, 

 but one would scarcely be justified in assuming that these 

 actions or symptoms result from their peculiar thyroid his- 

 tology. 



The histologic picture of the Maltese poodle thyroid is 

 shown by figure 2. The arrested fetal-like nature of this 

 gland is even more marked than that of the griffon thyroid. 

 The follicles are small and irregular in shape but the fol- 

 licular epithelium is high columnar, as if there was more 

 activity than in the griffon gland. Much of the epithelium 

 in the poodle thyroid has failed to enter into follicular forma- 

 tion and is seen as ramifying plates and cords of epithelium 

 in all parts of the gland. This thyroid shows extensive arrest 

 in formation of the normal follicular pattern, and the small 

 follicles that are present lie unusually far apart. The extent 

 of histologic distortion in this thyroid is best appreciated by 

 comparison with the normal glands (figs. 3 and 4 in this 

 plate) of the dachshund and great Dane, which show wide 

 contrast in structural pattern to figures 1 and 2 and again 

 emphasize the defective follicular conditions in the griffon 

 and poodle. 



The dachshund section (fig. 3) contains large and medium 

 sized follicles with low cuboidal epithelial walls. The colloid 

 is of medium hardness and the gland is in a state of low 

 activity. There are large groups of lightly stained parafol- 

 licular cells as well as some extrafollicular epithelioid tissue. 

 The follicular arrangement and types of extrafollicular cells 

 in the dachshund thyroid resemble in very close detail those 



PLATE 84 



EXPLANATION OF FIGURES 



Photomicrographs of thyroid sections from two midget dog breeds with spherical 

 crania and reduced facial skeleton (the Brussels griffon and Maltese poodle) 

 and two long-muzzled breeds (the dachshund and great Dane). 



1 Brussels griffon 278 $. 



2 Maltese poodle 79 <$. 



3 Dachshund 84$. 



4 Great Dane 175$. 



