CARCINOMA OF THE THYROID IN SALMONOID FISHES. 485 



TRANSMISSION OF THYROID DISEASE TO MAMMAl^. 



DOGS. 



In June, 1910, a dog obtained in Buffalo, and her litter of six young, were taken to 

 the Craig Brook station in Maine. They were placed in an inclosure near the fish ponds 

 and fed liver. They were immediately given to drink constantly water from pond 10, 

 and beginning with August 20 a pan of mud from the bottom of pond 10 with pond-io 

 water supernatant was supplied to them, the mud and water kept constantly renewed. 

 The animals not only drank the supernatant water but consumed the mud in quantity. 

 Seventeen days after the mud was first placed at their disposal all the puppies were 

 found to have palpable thyroid enlargements, besides greatly enlarged cervical lymph 

 nodes. This result was briefly reported at the Second International Cancer Congress at 

 Paris in 1910. 



The food of the puppies was changed to cereal, and upon examination late m Novem- 

 ber, 1910, all the enlargements had markedly decreased. Two of the animals, dogs 14 

 and 15, were shipped to Buffalo in December and killed. 



Section of the thyroid gland of dog 14, under the microscope presents an appear- 

 ance of the tissue easily discernible as normal. There is some variation in the size of the 

 follicles. The epithelium is flattened, the majority of the follicles filled with stainable 

 colloid. There are no evidences of hyperemia. Under high power the epithelium is 

 uniform in size, flattened, the protoplasm stains diffusely with hematoxylin, the nuclei 

 stain deeply, the long axes in the circumference of the lumen. There are no changes in 

 the stroma. 



Section of the thyroid of dog 1 5 shows a remarkable condition of the tissue. There 

 is but the slightest suggestion of follicular structure in the section. (See fig. 113.) 

 The entire tissue is made up of solid masses of epithelial cells, with deeply staining 

 nuclei. There is absolutely no trace of colloid in any portion of the section. Com- 

 pared with dog 14 the epithelial cells and their nuclei are distinctly enlarged. The 

 nuclei stain deeply. They vary in size and at some portions of the section are vesicular. 

 The protoplasm stains diffusely with nuclear stain and is distinctly increased in amount. 

 Under high power the outlines of the follicles can be traced by capillaries. The entire 

 alveolar space is filled with irregularly shaped epithelial cells lying somewhat loosely 

 packed in some regions, more compactly in others. In the more open portions of the 

 section a condition suggesting papillary projections into the alveoli of the lumen may 

 be made out. The nuclei are vesicular. Occasional karyokinetic figures are found. 

 We have here intensive proliferation of the epithelium, with complete disappearance of 

 the colloid. Marked parenchymatous struma. 



The remaining dogs of this lot were later shipped to Buffalo, and, at the last exam- 

 ination, made in July, 191 1, no palpable thyroid enlargement was present. Thyroid 

 regression influenced by the change from a high animal protein to low vegetable protein 

 may be inferred. 



A female brown spaniel (dog 24) obtained in Washington, D. C, was shipped to 

 the Craig Brook station in the fall of 19 10. On November 30 there was no palpable 



