324 DISEASE IN WILD MAMMALS AND BIRDS 
formly pale pink, somewhat dependent upon the blood 
content. By magnification one sees smaller acini with 
prominent high cuboidal or cylindrical epithelia and little 
or no colloid. The increase of cells seems to be due both 
to an increase in their size and number. As the pro- 
liferation increases the lining layer must be accommo- 
dated so that it bulges out into the lumen as a bud or 
papilla which, if it be extensive or universal in the 
thyroid, gives rise to the adenomatoid goitre of papil- 
lomatous TYPE. This growth is accompanied by much 
congestion and small or large hemorrhages may occur, 
forming cysts containing a blood-stained fluid. Grossly 
such a gland has solid and cystic areas, is mottled red and 
gray or bro^^^l from old pigmentation and is usually of 
very irregular shape. These forms are more or less 
uniform and general, but in certain instances the hyper- 
plasia tends to remain in isolated areas or nodules, and 
in these develop solid masses of thyroid epithelium, some- 
times with a small lumen usually devoid of colloid, and a 
rather rich but loose fibrous supporting tissue, the whole 
picture resembling the microanatomy of the fetal gland ; 
to these the name fetal adenoma has been given, but since 
they are not fetal in origin and do not behave like tumors 
I have called them nodular adenomatoid hyperplasias. 
The next step in hyperplasia would remove it from 
benign to malignant in pathological character, and the 
term neoplastic hyperplasia is used; this must of course 
be limited to the epithelial growths, since sarcomata, 
while they occur in the gland, come from other cells. 
The changes in atrophy consist in irregular distortion 
of the gland by fibrous tissue to which may be added large 
colloid or fluid cysts. There is no uniform finding in the 
thyroid for the diseases believed to be due to its atrophy, 
functionally at least, namely cretinism and myxedema. 
In the former there may be no thyroid, or it may rather 
closely resemble the normal organ while in the latter 
definite scarring and distortion is the rule. The gland 
