CARCINOMA OF THE THYROID IN SADMONOID FISHES. 
403 
junction. Figure 4, a view from above downward, shows a vegetating tumor in the 
floor of the mouth. Figure 2 illustrates an isolated tumor in the jugular pit, and figure 
5 a tumor in the jugular pit and one at the branchial junction. 
Pick’s paper is particularly excellent in the thoroughness with which he deals with 
the histology of these tumors. In fish i , with the large infiltrating tumor in the floor 
of the mouth, he recognizes the variegated character of the epithelial structure, distin- 
guishing an adenomatous portion and a follicular portion, both of which he closely 
describes. He points out the absence of any evidence of a capsule and describes fully 
and accurately the infiltrating character of the tumor tissue. He notes the extension 
of the tumor in the lymph spaces of the neighboring museular fascia, which he describes 
as being destroyed by the infiltration. Strands of tumor eells which widen into follicles 
invade the lymph spaces of the adventitia of the aorta. He describes the invasion and 
breaking up of the tendon of insertion of the muscle of the isthmus. The epitheUum 
of the tumor invades the loose submucous fatty tissue, and the spaces of the dense con- 
nective tissue and the tunica propria of the mucosa of the floor of the mouth. Not only 
are the softer tissues invaded, but he finds that both cartilage and bone are destroyed. 
This is accomplished by the tumor surrounding the bone growing into the various infold- 
ings of the branchial arches and the cavities of the bone, opening up the capsule of the 
cartilage, and invasion of the cartilage tissue proper, infiltration between the periosteum 
and the bone, thus leading to the death of fragments of bone and the formation of 
sequestra which through the process of decalcification and fibrillation disintegrate. 
In his description of fish 3 he shows, in figure 8, the invasion of the mucosa of the 
floor of the mouth by papillary outgrowths which, in the instance illustrated, shows 
the formation of small cystlike alveoli within the epithelium of the mucosa. In fish 5 
he describes and in figure 9 illustrates the solid type of tumor; in figure 10 is shown 
the polymorphic nature of the cells of this tumor. In fish 7 he describes portions of 
tumor with large cystic alveoli, flattened single layer of epithelium and stainable colloid 
(struma thyreoidea parenchymatosa colloides). In fish 8 the papillary type of growth 
is described. 
Pick concludes that these tumors are undoubtedly infiltrating epithelial neoplasms, 
malignant epithelioma, or in the general sense of Orth’s definition, carcinoma. He 
points out that the diffuse deposit of thyroid tissue does not necessarily become diseased 
in toto; in fact, that it is more often affected at various points, that the growths are 
pluri-centric. He thinks that these centers of growth originate simultaneously or at 
different times, that they may grow more or less uniformly and that in some cases 
outlying extensions of thyroid tissue become involved, these facts explaining the remark- 
able variety of form of the tumors, the directions in which they infiltrate, whether 
upward into the floor of the mouth or laterally into the gill spaces, and the fact that they 
may be bilaterally symmetrical or unsymmetrical. 
He points out the absence of a capsule in any of the tumor fish. He reeognizes 
that several of his tumors have retained very definitely the thyroid structure and speaks 
of these as presenting the character of parenchymatous struma, although in such tumors 
the infiltrative character and destruetion may be very great, these being tumors of 
