8 
Before considering the main problem, however, a few words may 
be devoted to certain phases of the older history of the thyroid. The 
relation of iodine to this gland had been for many years a matter of 
interest to physicians and was much discussed even before Baumann’s 
important discovery. It has long been recognized that iodine has 
some special relation to the thyroid. Seven years after the discov- 
ery of the element iodine by Courtois, in 1812, Straub, of Berne, sug- 
gested that it was the active principle of the “ toasted sponges” 
(Spongia “usta” or “tosta”) and the “Aethiops vegetabilis,” which 
had been used in the treatment of goiter at least since the thirteenth 
century.® Since 1820 iodine, as such or in combination, has been in 
constant use in the treatment of diseases of the thyroid. 
About the middle of the last century great interest was aroused by 
the work of Chatin, Marchand, and others on the relation of iodine 
in drinking water to goiter. The more recent history of this subject 
began with the revival of interest in the physiology and pathology of 
the thyroid gland which was stimulated by the work of Gull and Ord 
on myxoedema and of Kocher and Reverdin on the effects of the 
removal of the thyroid in man. This work was followed, partly as a 
result of the stimulus of Brown-Sequard’s ideas concerning internal 
secretion, by the introduction of organotherapy in the treatment of 
diseases of the thyroid. The brilliant results of this form of treat- 
ment led to the search for an “ active principle,” and this work cul- 
minated in the discovery of iodine in the thyroid by Baumann. In 
the year of Baumann’s discovery Kocher, * * * 6 who had been much im- 
pressed by the similarity of the effects of iodine and thyroid in the 
treatment of goiter, had suggested the desirability of examining the 
thyroid for iodine; the tests made in Berne were, however, negative. 
Baumann at first considered the iodine containing substance which 
he isolated and called iodothyrine to be the active principle of the 
thyroid; although he recognized later that in the gland much of this 
iodothyrine is in combination with proteins, neither he nor his. co- 
workers seemed to have entertained any doubt that the iodine was 
very important for the physiological activity of the thyroid. 
Following Baumann’s, disco very, determinations of the amount of 
iodine were made in the thyroid in a great variety of conditions; the 
influence of health, disease, sex, pregnancy, age, locality (near or 
remote from the sea, on the plains, and in the mountains), diet, cli- 
mate, etc., was investigated. The amount of iodine in the thyroids 
of a great variety of animals was also determined. Far-reaching con- 
clusions were drawn from such studies, especially as regards the rela- 
tion of iodine to the diseases of the thyroid itself (various forms of 
a cf. E. Hamack, Munchen. med. Wchnschr., 1896, 43, p. 196; G. Monery, Fonction 
iodee de la glande thyroide, Thesis, Lyons, 1903; Th. Kocher, Die Therapie des Krop- 
fes, Deutsche Klinik, Berl. and Wien, 1905, 8, p. 1115. 
6 Th. Kocher, Cor. Bl. f. schweiz. Aerzte, 1895, 25, p. 3. 
