CARCINOMA OF THE THYROID IN SAEMONOID FISHES. 
493 
mine whether or not extensive constitutional disturbances can be produced with the 
agent which we hold responsible for carcinoma of the thyroid in fish will require extensive 
experiments with young animals carried over a longer period of time than our experi- 
ments have thus far encompassed. It is quite clear from these experiments that there is 
a most intimate relation between the experimental production of goiter and the develop- 
ment of malignant disease of the thyroid in mammals. The infiltration of the capsule 
in dog 1 8 is extremely suggestive. Further experiments with older animals carried over 
a considerable period of time will be necessary before it can be definitely determined 
whether or not the agent responsible for carcinoma of the thyroid in trout is capable of 
producing infiltrating, possibly metastasising tumors in mammals. Bircher’s experi- 
ments in producing nodular struma in rats makes the outlook in this direction promising. 
The first attempts to produce experimental goiter in the lower animals by giving 
them to drink water from goitrous sources were undertaken by Klebs and H. Bircher 
(1883?) who, however, did not arrive at successful results. Carle in 1888 and Lustig 
in 1890 succeeded in producing in both dogs and horses, in regions free from goiter, 
enlargement of the thyroid as the result of giving them water from goitrous sources 
over a period of months. The most elaborate and carefully studied experiments are 
those by E. Bircher, jr., above referred to. Since his observations Repin (1911) and 
Breitner (1912) have carried out experiments and confirmed his results especially in 
rats, dogs, and monkeys, their experiments likewise extending over several months. 
Dieterle, Hirschfeld, and Klinger (1913) have repeated the experiments of Bircher, 
Wilms, Repin, and others, and arrive at the following conclusions; That in regions in 
which goiter is endemic it is possible to produce goiter in rats by giving them copious 
amounts of water to drink. Their success ranges from 40 to 70 per cent. Second, the 
nature of the water which is used in a goitrous locality is without significance. The 
water may be either fresh or boiled, and goiter may be produced with water which at 
the point of its origin is not a goiter-producing water. Rats in a goiter-free locality 
in Zurich which were given goiter water from other localities did not at first develop 
goiter. Later, however, a few positive results were obtained, but it was felt that con- 
tact infection could not be excluded. Because it is possible to develop goiter in rats 
in goiter regions with water from goiter-free localities, they conclude that the primary 
character of the water is not the determining factor in the development of goiter. 
They point out that in goiter localities boiling the water does not protect experimental 
animals against the development of goiter, but that in goiter-free localities boiling the 
water destroys the goiter-producing character of such water. They conclude that this 
indicates that the etiologic agent of goiter must be occasionally transmitted through 
the water. These experiments conform with the work, as yet unpublished, of Land- 
steiner, Schlagenhaufer and Wagner, and v. Jauregg, which will show that rats which 
were given nothing but boikd water from Vienna and kept in a peasant’s house in the 
neighborhood of Rothenthurm in Judenburg, in Steiermark, in which all the inmates 
of the house were either goitrous or cretinic, developed goiter in a percentage equal to 
that obtained with rats, using the goitrous water of that locality, whereas attempts to 
produce goiter in rats in Vienna with the goiter water of Rothenthurm gave only nega- 
tive results. 
60289° — Bull. 32 — 14 32 
