The analyses and experiments embodied in this paper comprise the second stage of the work on the nature of goiter, viz.: the relation of iodin to the structure of the thyroid gland.In previous papers one of us1 discussed the structure of the thyroid in its various phases in the attempt to formulate basic anatomic types to which the individual glands could be referred. It was found that the various types of changes are quite easily separated into four natural groups, viz.:
It has also been pointed out2 that the anatomic changes observed in developing goiters are of such nature, and occur under such peculiar conditions, and can be controlled by such particular procedures, that we are forced to conclude
(1) Normal glands.
(2) Glandular hyperplasias, all degrees (parenchymatous hypertrophies).
(3) Colloid glands, goiter (all degrees).
(4) Complications supervening in any of the three preceding groups.