462 BULLETIN OF THE BUREAU OF FISHERIES. 



aooa B. The amount of thyroid tissue surrounding the vessels is very scarce. Vesicles small, epithelium flattened, filled vrith 

 stainable colloid. Normal thyroid. 



2003 A. Alveoli small and lined with high columnar epithelium, deeply staining nuclei. Colloid absent. Follicles few in 

 number and poorly staining. Occasional groups of vesicles of normal appearance. Beginning invasion of areolar tissue. Dense 

 connective tissue structure. Growth into bone cavities. Definite alveolo-tubular type bef;inning carcinoma. 



2004 A, B, C. Space about vessels rather well filled with small-sized vesicles relatively uniform in size. Epithelium is flat. 

 tened. Vesiclesare filled with stainable colloid. In one small area close to a large vessel area half dozen follicles in which the 

 colloid is small in amount, the epithelium cubical. Normal thyroid. 



2005 A. This is evidently one of the tumor fish introduced into this experiment. Large amount of thyroid tissue. Great 

 variability in the size of the follicles. Large regular shaped follicles lined with flattened epithelium and filled with stainable colloid. 

 Large numbers of small follicles with cubical or flattened epithelium. Varying amount of colloid . Large amount of hyaline con- 

 nective tissue stroma. Obviously a tumor which has undergone regression. Tumor tissue fills the entire space around the vessel, 

 penetrates to the floor of the mouth, and into the bone cavities. It has previously invaded and destroyed large areas of muscle. 

 Contains numerous nematode tubercles, in which no worms are to be found. Spontaneous recovery. See fiuther under that 

 heading. 



2CK>5 B. Very few follicles included in this section. Flattened epitheUum filled with stainable colloid. Typical vesicles. 

 Normal. 



2005 C. Evidently tumor fish introduced into this experiment with spontaneous recovery like 2005 A. Contains two nema- 

 tode tubercles, in one of which remnants of a worm can be seen. 



2006 A. B. Thyroid consists of typical vesicles with flattened epithelium filled with stainable colloid. Normal. 



2007 A. Space around the large vessels contains scattered follicles filled with stainable colloid, lined for the most part with 

 flattened epithelium. There is marked hyperemia, marked engorgement of the vessels between the folhcles, and evidence of 

 small extravasation about the follicles. A few follicles are lined with cubical epithelium. Hyperemia of the thyroid, possibly 

 beginning hyperplasia 



2007 B. Tissue badly preserved, evidently overheated in embedding. Shows section of media of aorta arotmd which are 

 areas of closely packed large foUicles, lined with cubical eptheUura. No colloid. Beginning hyperplasia. 



2008 A, B. Small follicles lined with flattened epithelium, filled with stainable colloid. Normal. 



2008 C. Thyroid tissue in this fish consists of rather compact masses in tlie region of the large vessels. The epithelium of 

 some follicles is sUghtly cubical. Folhcles are filled with stainable colloid. Some evidence of hyperemia in the vessels between 

 the foUicles. Slight hyperemia of the thyroid. Probably normal. 



2009 A, B. Follicles oval and spherical, fined with flattened epithelium, filled with stainable colloid. Normal. 



2010 B. Vesicles Uned with flattened epithelium, filled with stainable colloid. Normal. Around the large vessels the thyroid 

 follicles are closely packed; the colloid is reduced in amount but stains deeply. Epithehum is small, cubical. Probably normal. 

 Thyroid tissue greatly increased in amount but of normal appearance. 



2010 C. Spherical and oval folUclesfclined with flattened epithelium filled with stainable colloid. Normal. 



2011 A. Follicles lined with flattened epitheUum. filled with stainable colloid. Between the folUcles hyperemia of the ves- 

 sels. Some evidence of extravasation. Hyperemia of the thyroid. Probably normal. 



2011 B, C. Spherical and oval folUcles Uned with flattened epithelium, filled with stainable colloid. Normal. 



2015 B. Closely packed follicles of irregular shape with almost complete absence of colloid. FoUicles lined with cubical 

 epitheUum. Small groups of detached folUcles lying outside the closely packed area Uned with flattened epitheUiun and filled 

 with stainable colloid. First evidences of hyperplasia. Beginning simple hyperplasia. 



2015 C. Between the second and third gill arches the space is filled with loosely arranged folUcles. many of which contain 

 stainable coUoid and are Uned with sUghtly cubical epitheUum. Between the folUcles, marked hyperemia and engorgement of 

 the vessels. Away from this mass in this area of sUghtly altered thyroid one finds isolated typical normal folUcles with deeply 

 staining colloid and flattened epitheUum. Again, about the aorta above and below it, one finds one or two aggregates of follicles 

 with sUghtly cubical epitheliiun and evidences of hyperemia. The remainder of the thyroid tissue about the large vessels strictly 

 normal. Hyperemia of the thyroid, possibly beginning hyperplasia. Unusual amount of thyroid tissue. 



2098 A. Tumor. Typical alveolo-soUd carcinoma for the most part, with areas of papillary formation. Infiltration of muscle, 

 bone, and cartilage. Infiltration of waU of vein. Papillary adenoi-carcinoma infiltrating muscle bone and cartilage. HyaUne 

 degeneration of the wall of the media of the aorta. (Fig. 90.) 



2098 B. Beginning adeno-carcinoma of tubulo-alveolar type. Infiltration of areolar tissue, dense connective tissue structures, 

 periosteum of bone and muscle. 



2099 A. Examination of this section shows an unusual amount of thyroid tissue about the large vessels, small foUicles Uned 

 with flattened epithelium, some of them containing stainable colloid, others poorly stained colloid, many of them empty, pushed 

 in flattened strands between the dense connective tissue structures, spreading wcU forv.ard into the areolar tissue and in the 

 adjacent bone cavities. (Fig. 91.) Great increase in the amount of thyroid tissue. Only one or two large folUcles filled with 

 stainable colloid. Immediately adjacent to the large vessels a few folUcles with high cubical epitheUum and no colloid. The 

 whole specimen indicates the previous existence of well-developed hyperplasia followed by regression. 



2099 B, C. Presents the same histological characteristics. Increased amount of thyroid tissue. Many isolated groups 

 widely distant from the large vessels. About the large vessels are many tortuous elongated and branching alveoli of tubular 

 type, Uned with flattened epitheUum. free from colloid. (Fig. 93, under "Spontaneous Recovery.") Colloid almost entirely 

 absent. 



