14 
(nebensachlicher Bestandteil) of the thyroid and its secretion?” 
He further states that the fact that in the body iodine is found 
chiefly in the thyroid “does not proye that the iodine is necessary 
for the activity of this gland: it may be explained by supposing that 
the thyroid has, among other functions, that of taking up an excess 
of iodine in the blood and storing it.” 
Seyeral other recent writers haye expressed somewhat similar 
yiews.° This point of yiew is, howeyer, by no means new; Boos * * * 6 
referred to it in 1899 in the following words: 
To consider the accumulation of iodine in the thyroid as an accidental process 
which has no greater significance for the body than the storing up of certain metals 
in the liver seems to me to he a very unsatisfactory conception ; for on it it is entirely 
unintelligible why the thyroid should use the iodine for the making of a substance 
(iodothyrine > which has such a marked effect upon metabolism and myxoedema 
instead of combining it in a much less active form, as occurs when iodine is allowed 
to react with proteins outside of the body. 
Such studies as the aboye (they may be called statistical studies) 
haye imdoubtedly brought to light many facts, some of which are 
difficult to satisfactorily explain. Still they do not seem to us to 
weaken the conclusion that iodine is an important constituent of the 
thyroid. All the writers who haye discussed this subject seem to 
haye taken one of two extreme yiews — that iodine is necessary to any 
physiological actiyity, or that it has no part at all in rendering the 
thyroid actiye. Xo one seems to haye suggested an intermediate 
yiew, yiz, that thyroid free of iodine may hawe a certain degree of 
actiyity, although this is much less than that of thyroid containing 
iodine, until one of the present writers discoyered that it is distinctly 
actiye in altering the resistance of animals to certain poisons. 0 This 
subject will be discussed in detail in the experimental part of this 
section. It will suffice for the present to state that we belieye 
this conception and the conclusions that may be drawn from it go 
far toward answering the arguments for the unimportance of iodine 
which haye been drawn from statistical studies. 
b. Physiological inactivity of artificially iodized proteins and colloid . — 
The question of the relation of the iodine to the actiyity of the thyroid 
was approached experimentally by Hutchinson/ who prepared an 
artificial iodized nucleo-albu min from the thymus of ealyes. Samples 
of it contained from 4 to 7 per cent of iodine; it had no effect in 
myxoedema or upon the pulse, temperature, or weight of subjects to 
whom it was administered. Heflin 6 had previously found iodized 
a Bunge, Lehrbuch der Physiol, des Mensch., 2d ed., 1905, 2, p. 631; S. J. Heltzer, 
X. Yorker med. Monatschr., 1907, 19, p. 223; Abderhalden, Lehrbuch der physiol. 
Chem., 1907, p. 647. 
6 E. Boos, Ztschr. f. physiol. Chem., Strassb., 1899, 28, p. 59. 
c B. Hunt, J. Am. M. Ass., 1907, 49, p. 1325. 
d B. Hutchinson, J. Physiol., 1898-99, 28, p. 181. 
e D. Heflin, Arch. £. exper. Path. u. Pharmakol., Leipzig, 1897, 40, p. 121. 
