412 
BUIvIvETIN of The bureau of fisheries. 
are best observed in the wall of the large vein, where we find the cells in small groups 
slightly suggesting an alveolar structure where they have penetrated into the media 
of the venous wall. Shrinkage owing to fixation accentuates the chopped out 
appearance of the media. (Fig. 68.) In studying the various sections in which this 
vein is included one finds a point at which the venous wall is greatly thinned, and at 
this point extensive hemorrhage into the surrounding tumor structure has occurred. 
In the same section groups of tumor cells are to be found in the venous lumen. (Fig. 
69.) We have here penetration of vessel walls by the tumor cells. Unfortunately, 
owing to the fact that we had only the head of this specimen to study, we do not know 
whether the viscera contained metastases or not. 
In the brook trout from Hosmers Creek, N. Y. (diagram 23, p. 30), the tumor pre- 
sents itself in the gill spaces on both sides of the isthmus, on one side shaping itself into 
a mass the size of a hazelnut. Protrusion in the floor of the mouth is visible between 
the first and second gill arches on the side of the large tumor and in the median section 
it infiltrates the region below the first and second gill arches. The fish is preserved 
in alcohol. Fixation is moderately good. The section of the tumor measures ii by 
9 mm. On macroscopic inspection of the section a deeply staining, sharply defined 
nodule measuring 6 by 8 mm. is clearly discernible embedded in a more lightly staining 
tumor mass. Inspection under low power shows that there is a distinct difference in 
the appearance of the surrounding tumor and the nodule, the nodule being separated 
from the tumor by a well-defined compression capsule. (Fig. 70.) The outlying 
portions of the tumor are for the greater part composed of small alveoli, somewhat 
loosely arranged, with occasional larger alveoli of irregular shape and marked columnar 
epithelium. Wide venous channels are frequent in this portion of the tumor. Within 
the capsule of the above-described nodule one finds the whole made up of somewhat 
loosely arranged islands, strands, and masses of cells. The central portion of the 
nodule presents wide venous sinuses without delimiting intima and areas, which are 
no doubt the result of hemorrhage. Under high power one finds the cells in certain 
portions of the nodule to be so arranged as to suggest small alveoli, but for the greater 
part, especially in the well-preserved marginal portions of the nodule, the cells present 
a distinct spindle character, and great variability in size of the nuclei, which are vesicular 
with one or two nucleoli. The protoplasm of the cells stains deeply, is rather sparse, 
and karyokinetic figures are very numerous. Certain areas may be found in which 
the spindle character of the cells is so pronounced as to suggest the diagnosis of spindle- 
celled sarcoma. (Fig. 71.) Gradual transitions of such areas into an arrangement of 
cells clearly showing their derivation from the poorly formed alveoli indicate their 
character. We have here a nodule of malignant tumor growth in a mass of tumor 
tissue of less malignant appearance, carcinoma solidum simulating spindle-celled 
sarcoma. 
In June, 1913, a large landlocked salmon (S. sehago) with a large thyroid tumor 
was caught in Sebago Lake, Me., by Dr. Charles F. Parker, of North Windham, Me. 
Dr. Parker recognized the nature of the growth and forwarded it to us through Dr. W. C. 
Kendall, of the Bureau of Fisheries. The fish was about 4 years of age, measured 23 
