432 CHARLES It. STOCKAED AND E. M. VICARI 



to show as wide a variation in histologic structure as could 

 be found. The differences among the three sections photo- 

 graphed at the same magnification arc very slight. The fol- 

 licles in all arc large, and the extrafollicnlar tissue is very 

 scarce. The third section (fig. 4, pi. 83), with low cuboidal 

 follicular lining and no droplets, shows much the lowest 

 activity and was taken from a timid male dog that had never 

 been a vigorous animal. It is used to illustrate the most 

 aberrant condition found for shepherd thyroid histology. None 

 of the differences among the shepherd thyroids tends to 

 approach in the slightest degree the patterns shown by the 

 bulldog typed glands, irrespective of whether they were active 

 or inactive at the time of death. 



Figures 1 and 3 in plate 83 illustrate for the St. Bernard 

 thyroid the widest deviations from the typical section of 

 32(5 9 (fig. 4, pi. 82). Figure 1 is from the thyroid of 86 9. 

 This section illustrates the nearest approach to hyperthyroid 

 reaction found among glands from about one dozen adult St. 

 Bernard specimens. All the sections arc photographed at 

 the same magnification, as can be seen by a comparison of 

 nuclear size. Thus may we appreciate the excessively large 

 sizes of the secretion droplets surrounding the colloid, as 

 well as the extremely high columnar epithelium in this 

 section. The animal from which this gland was taken was 

 killed while suffering from an acute attack of gas formation 

 throughout the gastro-intestinal tract. This distended the ab- 

 domen enormously causing severe pain. Until only a few 

 hours before death the animal had always been in vigorous 



PLATE 83 



EXPLANATION OF FIGURES 



Photomicrographs of thyroid sections from the St. Bernard and German 

 shepherd. These sections were chosen to show the widest differences to be found 

 in thyroid histological structure in the two breeds concerned and should be 

 studied in conjunction with figures 3 and 4, plate 82. 



1 St. Bernard 86$. 



2 German shepherd 111 $. 



3 St. Bernard 18(3$. 



4 German shepherd 1404 £. 



