CARCINOMA OF THE THYROID IN SALMONOID FISHES. 

 TABLE VIII. FEEDING AND OTHER EXPERIMENTS WITH WILD BROOK TROUT. 



461 



Examinations of Nov. 30, 1910, and July, 1911, all were clean. 



6 Transferred to pond 10. 



DESCRIPTION OF SECTIONS TO ACCOMPANY TABLE VIII. 



2000 B. Tubulo-alveolar type of carcinoma. Marked infiltration of surrounding areolar tissue. Infiltration of muscle above 

 into bone spaces and infiltration of vessel wall. Invasion of cartilage. 



2001 A. Beginning hyperplastic stage. Certain follicles are lined with columnar epithelium. In many such follicles colloid is 

 absent, in others present but poorly stained. Surrounding this group of follicles are follicles of strictly normal appearance. Epi- 

 thelium flattened, filled with colloid. Beginning of the hyperplasia in this specimen is evidently limited to individual follicles 

 (Fig. 84.) 



2001 B. Most of the thyroid tissue in this specimen is of typical normal appearance, flattened epithelium, follicles filled with 

 stainable colloid. 



2001 C. The entire space surrounding the vessel is filled with closely packed alveoli, small sized alveolar structures lined with 

 high columnar epithelium, with deeply staining vesicular nuclei. Colloid is almost entirely absent. Evidently growth of the 

 thyroid tissue which has spread upward into the areolar tissue immediately below the mucosa of the floor of the mouth. Under 

 high power the nuclei present great variability in size, the staining qualities are vesicular with one or two nucleoli. Marked 

 evidence of hyperemia between the follicles. Many tubules are filled with closely packed cells. In some portions of the 

 growth all alveolar structure has disappeared and small islands of closely packed cells are found. Infiltration of dense con- 

 nective tissue structure, perichondrium and periosteum. Beginning carcinoma of tubulo-alveolar type. 



