UC-NRLF
CARCINOMA OF THE THYROID IN THE SALMONOID
FISHES : : : By Harvey R. Gaylord and Miilard C. Marsh
Publications from STATE INSTITUTE FOR THE STUDY OF MALIGNANT DISEASE
Serial No. 99
Issued April 22, 1914
WASHINGTON
GOVERNMENT PRINTING OFFICE
CARCINOMA OF THE THYROID IN THE SALMONOID
FISHES : : : By Harvey R. Gayloid and Millard C. Marsh
Publications from STATE INSTITUTE FOR THE STUDY OF MALIGNANT DISEASE
Serial No. 99
Issued April 22, 1914
WASHINGTON
GOVERNMKNT PRINTING OFFICE
1914
S
(L3C 3
BIOLOGY
CARCINOMA OF THE THYROID IN THE SALMONOID FISHES
An investigation and experimental study conducted jointly by the
Gratwick Laboratory of the State Institute for the Study of Malignant
Disease, Buffalo, N. Y., and the United States Bureau of Fisheries
By Harvey R. Gaylord, M. D.
Director, State Institute for the Study of Malignant Disease, Buffalo, N . Y.
AND
Millard C. Marsh
Biologist, State Institute for the Study of Malignant Disease, formerly
Scientific Assistant, United States Bureau of Fisheries
WITH THE COLLABORATION OF
Frederick C. Busch, M. D., Internist, AND Burton T. Simpson, M. D., Pathologist
State Institute for the Study of Malignant Disease
363
CONTENTS.
j*
Introduction 367
History of the present investigation 367
History of the disease 369
Normal thyroid in salmonoids 373
Embryology 374
Gross anatomy and distribution in the adult brook trout 376
Anomalous deposits of thyroid 377
Histology 378
Simple hyperplasia and colloid goiter in wild and domesticated fish 379
Pathologic anatomy 382
Gross anatomy 382
Earliest macroscopic evidence 382
Visible tumors 383
Branchial junction 383
Floor of mouth 384
Pit tumors 384
Histology 397
Early stage 397
Red- floor stage 398
Visible-tumor stage — Structural types 399
Infiltration 400
Bone and cartilage; vessel wall; muscle; skin 401-402
Other observations 402
Implantations and metastases 404
Comparative pathology 407
Occurrence of the disease under wild conditions 411
Occurrence and course of the disease under domestication 413
Distribution of the disease in United States hatcheries 413
Names of species and hybrids 414
Geological formation at fish hatcheries 415
Chemistry of the water supplies 419
Dissolved oxygen 420
Endemic occurrence 424
Caledonia hatchery, New York 424
Craig Brook station: Conditions at the beginning of the investigation 425
Craig Brook station: Conditions during three years 428
Lake Auburn hatchery, Maine 435
Private hatchery in the State of Washington 436
Epidemic occurrence 436
365
366 CONTENTS.
Occurrence and course of the disease under domestication — Continued. Page.
Hybridization 441
Clinical course 441
Morbidity and mortality 441
Hemoglobin estimations 447
Spontaneous recovery. . . . .' 448
Immunity 450
Experimental production of the disease 453
Trout tumor material in standing water 453
Feeding trout thyroid tumor 453
Feeding human cancer liver 453
Closed circulation 453
Transplantation and inoculation experiments 454
Experimental induction of carcinoma 457
Chemotherapy — Effect of iodine, mercury, and arsenic upon carcinoma of the thyroid 463
Transmission of thyroid disease to mammals 485
Dogs 485
Rats 490
Possible carriers 495
Summary, in English 502
In German 507
In French 513
Conclusions, in English 506
In German 511
In French 516
Bibliography 519
Plates 524
CARCINOMA OF THE THYROID IN THE SALMONOID FISHES.
*
By HARVEY R. GAYLORD, M. D., and MILLARD C. MARSH
WITH THE COLLABORATION OP
FREDERICK C. BUSCH, M. D., and BURTON T. SIMPSON, M. D.
>
INTRODUCTION.
HISTORY OF THE PRESENT INVESTIGATION.
In 1907, by the natural trend of the general investigation into cancer which was
being conducted by the State of New York through the medium of the Gratwick Labo-
ratory, now a part of the State Institute for the Study of Malignant Disease, that
institution became interested in the possible distribution of cancer and allied affections
in fish. Through publications of Plehn and Pick the attention of cancer investigators
was attracted to a disease known as carcinoma of the thyroid in the Salmonidae. The
disease had been described in the literature under various names and was known to fish
culture as "gill disease," " throat tumor," etc. The work of Marianne Plehn had served
to establish the nature of the disease as cancer or carcinoma of the thyroid, intimately
associated with enlargement of that organ of a more simple nature which might be
considered goiter.
In 1907 the director of the Gratwick Laboratory took occasion to visit one of the
hatcheries in New York for the purpose of inquiring into the prevalence of this disease
in the hatcheries of the State. He learned that one or two fish with tumors at the
junction of the gills had been found and in the spring of 1908 a report came from this
hatchery that an epidemic was in progress, and an examination made on the spot
revealed the presence of visible tumors in some 700 fish. Attempts were made to study
the conditions under which the disease developed in this hatchery, and observations
were carried through the summer of 1908. Attention was called to the existence of the
disease in two other hatcheries in the State of New York, and at the conclusion of the
summer's work it became apparent that the great extent of the disease, the existence
of which in other States had been reported to us, was such that a comprehensive inves-
tigation could probably be successfully accomplished only in cooperation with the
United States Bureau of Fisheries.
367
368 BULLETIN OF THE BUREAU OF FISHERIES.
For this reason, in February, 1909, the results obtained and the importance of the
subject were laid before President Roosevelt, who decided that a joint investigation
between the Gratwick Laboratory and the Bureau of Fisheries should be undertaken.
The Commissioner of Fisheries, Hon. George M. Bowers, detailed Mr. Millard C. Marsh
as the representative of the Biireau to cooperate with the State. Facilities were at once
afforded for a detailed investigation at one of the Government fish hatcheries where the
disease was endemic.
The first summer's work was carried out by Dr. Gaylord at this Government
hatchery. In the winter of 1909-10 Mr. Marsh, working at the Gratwick Laboratory
in Buffalo, in conjunction with Dr. Gaylord, carried out a series of experiments on
feeding, crowding, vitiation of water, etc. The summer of 1910 was again spent by
Dr. Gaylord and Mr. Marsh at the Government hatchery in question. The winter of
1910-11 Mr. Marsh continued the work in Buffalo. In July, 1911, Mr. Marsh was
detailed for service in Alaska and Dr. Frederick C. Busch, of the State Institute for the
Study of Malignant Disease, took up his part of the work. In the pathologic histologic
part of the work Dr. Burton T. Simpson contributed largely, having studied many
hundred sections and recorded important facts. The experimentation at the Govern-
ment hatchery has been conducted to a point where it is now possible to make the first
report on the studies thus far conducted into this disease.
In this report we have attempted to determine the nature of this affection, to present
a well-defined picture of the disease as it occurs in hatcheries under conditions of
practical fish culture, to determine as nearly as possible the factors which predispose to
the development of the disease, and to present certain conclusions regarding its nature.
Identification of the agent which causes this disease we have left for future investigation.
How important to fish culture and how significant to cancer research future studies in
the more sharply defined field to which this report is an introduction will prove, may be
easily seen from the significant facts thus far adduced.
In our investigations and in the preparation of this report we have had assistance
from many persons to whom we wish here to acknowledge our indebtedness. The joint
investigation was begun during the incumbency of Hon. George M. Bowers as Commis-
sioner of Fisheries, and the resources and facilities of the Bureau were freely used by him
in furtherance of the mutual undertaking. Likewise, Dr. Hugh M. Smith, who as
Deputy Commissioner interested himself keenly in the encouragement of the work, has
since his recent appointment to the commissionership continued in every ..way to give
indispensable support and cooperation. The members of the fish-cultural and scientific
staffs of the Bureau in Washington, and superintendents and employees of stations,
have given much time and effort in various ways. Of the latter, Mr. C. G. Atkins,
superintendent of Craig Brook station, has been our chief dependence.
The Commissioner of Forest, Fish, and Game of the State of New York, Mr. James
S. Whipple, and the State Fish Culturist, Dr. T. H. Bean, have furnished valuable
assistance by placing at our disposal facilities and material at certain of the State hatch-
eries. The superintendents and employees at the hatcheries at Bath, Caledonia, and Cold
Spring Harbor gave much direct assistance.
CARCINOMA OF THE THYROID IN SAUMONOID FISHES. 369
The excellent plates in color and most of the other drawings are the work of Miss
E. S. Carrington, of Louisville, Ky.
Dr. F. W. Baeslack, formerly of the Gratwick Laboratory, autopsied a portion of
the tumor-fish material. Of the present force of the laboratory the work of Mr. Damon
Averill deserves special mention. He has had to do with the fish material from the
beginning of the investigation, has done a part of the histological work and all the
extensive photography involved; to the photomicrographs particularly, on which the
value of this report largely depends, he has devoted much pains and skill.
Miss C. A. Maclay, secretary of the State Institute, has had charge of many details
concerned in the investigation, has prepared much of the manuscript for the printer,
and taken part in the proof reading.
The translations of the summary and conclusions into German and French we owe to
the skill of Dr. Max Breuer and Dr. Charles van Bergen, both of Buffalo.
HISTORY OF THE DISEASE.
The existence of this disease was first noted in 1883 by a German investigator,
R. Bonnet, who published in the Bavarian Fisheries Journal the description of a peculiar
epidemic occurring among the lake trout (Trutta lacustris) at the fish hatchery in Torbole
on the Gardasee, and, between the middle of February and the end of June, killing no
less than 3,000 fish. All of these fish had tumors at the junction of the gills.
Bonnet did not recognize that this disease was cancerous in its nature. The first
to recognize the tumor as carcinoma was Scott (1891). The full text of his " Note on the
Occurrence of Cancer in Fish" is as follows:
The fish afflicted with this disease were all specimens of the American brook trout (Salmo fontinalis)
kept in confinement in one of the ponds at Opoho belonging to the Dunedin Acclimatization Society.
Males and females were alike affected and the diseased fish never recovered. Through the kindness
of Mr. Deans, the manager, I was able to examine several specimens showing the disease in various
stages of advancement, and the following is a short account of the naked-eye and microscopic appear-
ances of the growth.
In the earliest stages the ventral wall of the pharynx in the middle line, a short distance behind
the tongue, is seen to be somewhat roughened and raised in low irregular swellings. At this stage
nothing is to be seen unless the mouth is opened widely. As the tumor grows, however, not only does
it involve more and more of the pharyngeal floor, spreading also to a slight extent laterally, and involving
the ventral ends of the gill arches, but it ultimately shows itself externally as a rounded pink lump
on the isthmus in the angle between the diverging branchiostegal rays.
A microscopic section of the tumor shows all the stages in the development of a carcinomatous
growth. In parts a purely glandular structure is seen — the glands, apparently, of the acinotubular
type. Elsewhere, owing to the proliferation of the cells, the gland acini have become distended and
irregular in form (adenoma stage), while in large areas these overdistended acini have burst, as it
were, and the liberated cells, making their way into the stroma, infiltrate it, and all gland structure is
lost (carcinoma stage).
Of the two figures which accompany this note, the first (Fig. i) shows the floor of the mouth and
pharynx, as seen from above, of a fish suffering from the disease. The nodular character of the tumor
is clearly seen. The second shows a small portion of a section as seen under the microscope. A distended
acinus is seen liberating a stream of cells into the gland stroma (Fig. 2).
370 BULLETIN OF THE BUREAU OF FISHERIES.
The occurrence of cancer in the lower animals has been frequently noted of late years, and it is by
no means so rare among them as it was at one time thought to be. I have, however, been unable to
find any mention of it having been noted in fish.
A report on this disease in trout appeared in 1 902 in the General Fisheries Magazine
(German), by Marianne Plehn, who recognized it as a disease of the thyroid gland.
L> Pick reported fully on the subject in a paper entitled "Carcinoma of the Thyroid in
the Salmonidae," describing 10 fish affected with the disease, which, in agreement with
all other authorities, he concludes, is genuine cancer. He refers especially to the
epidemics of the disease, descriptions of which are found below.
In the reports of the New Zealand Department of Agriculture, Division of Veterinary
Science, 1901-2, is a report by Gilruth entitled "Epithelioma Affecting the Branchial
Arches of Salmon and Trout." Gilruth describes a specimen, a 5-year-old salmon (Salmo
salar) from the Clinton ponds, which had a growth on the third branchial arch and "its
gill ray." It was the first specimen which had been found there. His description is as
follows :
Macroscopical examination. — Growth appeared about the size of a marble, situated on the center of
the third branchial arch, affecting laterally the first and third and implicating the branchiae. The
gill cleft was distended, but until forcibly opened the tumor was not visible.
Later he received three rainbow trout (Salmo irideus).
In each specimen the tumor was about the size of a large walnut projecting on both sides of the gill
cleft. (Fig. 3.) Each tumor appeared to have started at the apex of the second branchial arch, about
the base of the branchiae, which they had implicated almost to their terminal points, only leaving a
faint fringe of what were the branchiae. The first and second arches, with their branchiae, were also
affected. The growth did not affect the apex of the the arch externally, but passed on the internal
surface through to both sides. The external surface of the tumor was faintly pink. On section the
tumor was found to be homogeneous, pale in color, and soft in consistency.
Microscopical examination. — Fibrous capsule, covered by several layers of squamous epithelium,
from which the fine fibers forming branching and anastomosing trabeculse pass inward, inclosing more
or less irregular alveoli. These alveoli are lined by an irregularly disposed layer of columnar cells, the
center of each alveolus being filled with cubical cells more or less degenerated. The smaller alveoli
are lined with columnar or cubical cells, and have the appearance of tubules cut transversely, the
central area only containing one or two degenerated cells. Blood vessels with thin walls and wide
lumina are found traversing the fibrous capsule and the fibrillar network within. Frequently hemor-
rhage is met with where the slender walls of the blood vessels have ruptured. In many portions of the
tumor the branching fibrillae with columnar cells on either side show an appearance recalling somewhat
the fronds of the common fern. Taking into consideration the histology of the branchiae with the above
description, it would appear that the only pathological classification, at least from the mammalian
standpoint, which this would come under, is epithelioma (as distinguished from carcinoma).
Gilruth gives a letter from L. F. Ayson, Chief Inspector of Fisheries, New Zealand,
who states:
This gill disease was first noticed there [Masterton hatchery] among the American brook trout
(Salvelinus foniinalis) in 1890, when three diseased fish were taken out that spawning season. The
disease was peculiar to this species until the rainbow trout (Salmo irideus) were introduced, among
which it made its appearance when they were over 3 years old. I have never found any of the
brown trout (S.fario) affected, but took out three diseased fish from a thousand 3 and 4 year old Loch
CARCINOMA OF THE THYROID IN SALMONOID FISHES. 371
Leven (S. levenensis) during the spawning season of 1896. In 1898 about 2 per cent of the American
brook trout over 3 years old would be affected and about i per cent of the rainbow trout over that age.
I have no record of ever finding any diseased fish under 3 years old.
With regard to the diseased specimens of rainbow trout which I brought to you recently, I visited
the Masterton hatchery on June 16, when the manager was engaged in shifting his 3-year-old rainbow
trout from their summer ponds into the spawning races, where they were sorted out, i. e., the male fish
were separated from the females and the ripe female fish from the unripe; the ripe fish being stripped,
and the unripe females and male fish being put into separate races. I assisted with the separating and
stripping that day, when 1,200 fish were handled. From this number 29 fish affected with this gill
tumor were taken out; these (with the exception of the specimens taken to your laboratory) were
knocked on the head and buried.
At the Otago Acclimatization Society's Opoho and Clinton trout hatcheries the American brook
trout are, I believe, the only fish affected with this disease, but at Christchurch hatchery I understand
that it is common among both the American brook and rainbow trout. If it is of any interest to you I
will get particulars from the Otago and Canterbury Acclimatization Societies with regard to this matter,
and will also inquire whether this disease has made its appearance at the Aukland Society's hatchery
at Okoroire , where only rainbow trout are kept.
Gilruth quotes Ayson further as the authority for the statement that at Masterton
he was present at the handling of 3,000 or 4,000 pond-spawning fish (1902) and that, from
these, loo fish affected similarly to those described were taken out and killed; also that
the manager of the Aukland Society's rainbow trout hatchery stated that 7 per cent of
the mature pond fish at that hatchery were affected.
Marsh in 1903 first reported the disease in the United States as an occasional
occurrence known to fish culturists, affecting yearling as well as older trout, and noted
the occurrence of marked anemia in affected fish.
In the Third Annual Report of the Imperial Cancer Research Fund (English), 1908,
in an article on the zoological distribution of cancer in fishes, occurs the following:
Since the first authentic case of carcinoma in a fish, viz. , of the thyroid gland in a trout, was submitted
to us in February, 1903, by Mr. Gilruth, over 2,000 additional cases have been reported to us from the
same and other hatcheries. * * * We have been unable to approach this extremely interesting and
important subject from the fact that up to the present we have been unable to find any evidence of its
occurrence in the hatcheries in this country at the present time, the last epidemic of the disease appear-
ing in 1888 in Scotland.
At a meeting of the Lyon Medicale in 1908 Jaboulay reported having had in his
laboratory for study six trout affected with malignant tumors of the thyroid gland.
These were sent to him in November by M. Crettiez, inspector of waters and forests of
Thonon. The disease had existed at the establishment at Thonon for three years and
had been first noticed by M. Crettiez in salmon hatched from eggs received from Germany.
He had recently observed the disease in sea salmon, ombres-chevaliers (Sahelinus
alpinus), and in the offspring of one hybridization formed by crossing the common
female trout with the male ombres-chevaliers, to which he had given the name Salmo
thononensis. To Crettiez the disease appeared to be clearly hereditary and at the same
time contagious and always fatal, although any elaboration of his grounds for these
conclusions is not given by Jaboulay. Jaboulay considers the tumor an adeno-carcinoma
of the thyroid, which he says invades the thyroid region and the neighboring tissues and
in its last stages generalizes in the various organs.
372 BULLETIN OF THE BUREAU OF FISHERIES.
In the United States the disease has been known to fish culture for some 40 years,
but has escaped mention, so far as we have been able to find, in the several treatises on
fish culture which have been written in this country, and has not until recently been the
subject of any particular study.
From time to time during the progress of this investigation we have made prelimi-
nary statements before the American Association for Cancer Research. These brief
summaries are here reprinted in order to show the development of the investigation along
the lines originally indicated.
AN EPIDEMIC OF CARCINOMA OF THE THYROID GLAND AMONG FISH.°
Dr. Harvey R. Gaylord, Buffalo: This paper is a continuation of a preliminary report made before
the society a year ago. It gives details of two epidemics in different parts of the country, and refers to
two others. The epidemic referred to last year, which resulted in the loss of 3,500 brook trout, had,
during the summer of 1909, begun to involve the brown trout and adult rainbows, so that heavy losses
continued during this summer. Among the fish preserved from this epidemic was one with a tumor
on the lower jaw, which on section was found to be either an implantation of the thyroid tumor or a
metastasis, as the fish so affected had a primary tumor of the thyroid. From this observation it is plain
that this tumor may, under given conditions, metastasize, or that it is implantable. In an epidemic
in a second hatchery, an analysis of the course of the disease again showed that where fish occupied
ponds which received water from ponds containing infected fish, these fish may become infected;
and, furthermore, the rate at which the fish become involved increases progressively as the contents
of ponds containing infected fish are added to the water which supply the fish. Another observation
of importance is the discovery that lots of fish are immune. This is particularly shown in hybrid fish,
in which one lot of hybrid salmon i year old were reduced from 1,043 m April to 44 sound fish remain-
ing in August, whereas another lot of yearling hybrid salmon, although badly exposed by being placed
in ponds into which the water from infected ponds ran, remained free from the disease throughout.
Three lots of Scotch sea trout remained immune, although badly exposed. The only lot of brook trout
2 years old which were free from the disease was found on a careful analysis of their position throughout
their entire life history in this hatchery, never to have been placed where the water from infected troughs
or ponds flowed to them. They were placed in the uppermost pond and remained free from the disease
throughout the epidemic. These observations on immunity in hybrid fish, in the light of those made by
Tyzzer in inoculation of Japanese waltzing-mouse tumor, in hybrids from immune and nonimmune
parents, serve to accentuate the similarity of this disease in fish to cancer in warm-blooded animals.
The disease is found to affect very small fish. A brook trout of the hatch of 1909, 3 inches in length,
was shown with a tumor of considerable size from which it had died. This was the first affected fish
from the hatch of 1909, and it had occupied from May until September one of five troughs which had
the previous summer contained infected fish. From this it would appear that the contagion can be
localized, even to given, small wooden troughs, and that these troughs can retain their infectivity from
year to year. In all the epidemics thus far described, occasionally large fish, when exposed, acquire
the disease. A landlocked salmon 8 years old, measuring 24 inches in length, developed large tumors,
and in two other hatcheries during the past year epidemics have broken out involving considerable
numbers of adult rainbow trout and large adult brook trout. Among the large fish epithelioma of the tongue
or the region of the mouth is not uncommon. Carcinoma of the thyroid produces the most rapid destruc-
tion among young fish, frequently diffusely infiltrating the gills and also growing to great relative size
in the small fish. The tumor erodes bone, destroys cartilage, and infiltrates the muscular structure.
The tumor presents varying characteristics, frequently retaining the alveolar type with colloid, again
of a strictly adenomatous type, but in all cases with areas of complete malignant degeneration and
assuming the characteristics of solid soft carcinoma.
o American Association for Cancer Research, meeting of Nov. 27, 1909, Journal American Medical Association, Jan. 15, 1910.
CARCINOMA OF THE THYROID IN SAUVTONOID FISHES. 373
In the study of this interesting form of cancer, the discovery of metastasis formation, the evidences
of immunity, and the influence of blood relationship to susceptibility show the practical identity of
this affection to cancer in warm-blooded animals. The apparent absence of metastasis formation as a
criticism was long since applied to mouse cancers and to-day falls to the ground in this affection. The
evidence of infectivity and contagion appear to the observer to be conclusive, and when correlated in
the evidence of infectivity in cancer in warm-blooded animals should prove the greatest support to the
parasitic theory we have yet encountered. The marked evidence of infectivity and contagion found
in carcinoma of the thyroid in fish appears to be an accentuation of similar evidence of a less convincing
character found in other species. Its accentuation in this disease can be largely explained by the envi-
ronment and the conditions under which fish are artificially propagated.
AN EPIDEMIC OF CANCER OF THE THYROID IN BROOK TROUT IN A FISH HATCHERY.0
Dr. H. R. Gaylord, Buffalo: This is a preliminary report on the investigation of a fish hatchery in
which an epidemic of carcinoma of the thyroid in a-year-old brook and brown trout exists at the
present time. In this hatchery the water supply is from a spring coming out of a hillside, which runs
into a basin or pond, from which it is piped to a small reservoir and then through a series of tanks which
draw their supply directly from the reservoir. Carcinoma of the thyroid was discovered in a fish in the
basin on the hillside two years ago. One year ago this basin was emptied and restocked with young
fish and feeding was practiced for the first time in this upper pond. Of the tanks fed from the water
passing through this pond, one tank containing 3,700 brook trout 2 years old, hatched from eggs brought
from a hatchery in an adjoining State where the disease is not known to exist, showed 700 fish in various
stages of the disease. The outbreak occurred in the early autumn and fresh cases are continually devel-
oping. In an adjoining tank, which has no connection whatsoever with the tank in question, are 200
brown trout reared from eggs hatched on the premises. Between 3 and 4 per cent of these fish show
disease. The infected fish at no time have come in direct contact with the fish in the upper pond
where the disease is known to have existed ; neither at any time have the brook trout and the brown trout
been in contact with each other. I believe that the state of affairs found in this fish hatchery points
very strongly to the infectious nature of this form of cancer and that the contagion is water-borne. It
is possible that feeding liver into the waters of the fish hatchery has some relation to the outbreak in this
case. I know of a second fish hatchery where the disease was endemic for a number of years and where
the feeding of liver has been changed to the feeding of chopped sea fish and in the last three years the
disease has disappeared. I also know of two other fish hatcheries in which the disease is endemic, and
I am undertaking a systematic and careful study of a number of fish hatcheries for the purpose of further
determining the conditions under which the disease occurs.
NORMAL THYROID IN SALMONOIDS.
The thyroid in fishes has given rise to a not inconsiderable literature, beginning with
Simon's paper (1844) on the comparative anatomy of the gland, in which he first identified
the thyroid in fishes. The detailed studies of its histology belong to a much later period.
Most of the work has been upon genera outside the Salmonidae, and especially upon the
lower forms of fishes. Maurer (1886) described and illustrated the development of the
thyroid in a trout, and the location of the thyroid follicles in the adult, with a semi-
diagrammatic drawing of the histology of the adult follicles. In 1910 and 1911 Marine
and Lenhart published photomicrographs of normal thyroid in the brook trout in
illustration of studies of enlargement of the gland. Thompson in 1911 published a
paper on the thyroid and parathyroid of vertebrates, with Amiurus as the only teleost
» American Association for Cancer Research, meeting of Nov. 37, 1908, Journal of American Medical Association, Jan. jo. 1909.
374 BULLETIN OF THE BUREAU OF FISHERIES.
representative. In 1911 Gudernatsch, in the most extended study of the fish thyroid
that has yet appeared, diagramed the distribution of the follicles in 22 genera of teleosts
including 4 genera and 5 species of salmonoids, and showed the minute structure in
several genera including 2 species of salmonoids, viz. , a Pacific salmon and the American
brook trout (Salvelinus fonfanalis}. He was the first to emphasize, in a preliminary
statement before the American Society for Cancer Research (Nov. 27, 1909), the lack of
a capsule in the thyroid of teleosts.
It is thus seen that a number of studies having to do with normal fish thyroid have
been made, and are widely scattered among the many and diverse genera of this great
class. Not until recently has any particular attention been focused upon the Salmonidse.
The amount, distribution, and structure of the gland may be said to have been shown for
individuals whose source and history and the conditions under which they had been
living are not well known or are not stated, but which are presumptively normal and
show no obvious pathologic changes. If, however, one limits the normal to the minimum
of the thyroid exhibited by adults from streams far from and unaffected by civilization,
where the fish are obviously living strictly in a state of nature, there is yet but a meager
exposition of the normal thyroid in the salmonoids. We believe that the final comparison
is to be against a norm set up by such individuals, and that most trout from aquariums,
markets, fish-cultural establishments, and from artificially stocked streams and lakes or
unstocked streams or lakes close to civilization or much frequented by people, have
either abnormal thyroids or are not to be judged by criteria obtained from strictly
wild trout.
In our specimens of wild brook trout we are unable to find the thyroid distributed
as widely and in such quantity as shown by Gudernatsch (1911, a, p. 753 and pi. n) for
this species. He finds it extending into the gill arches, infiltrating muscle bundles and
in places completely filling the available thyroid spaces. We find these conditions in
domesticated fish, but not in our wild specimens. His material was in part obtained from
aquarium fish, and in such we would expect such a distribution. It may even occur
in specimens from some streams or lakes. We would infer that all fish exhibiting it
may be presumed to have been under influences foreign to those usually obtaining in
strictly wild natural conditions, but they may perhaps be considered to represent a
normal for trout under a modified regime without presumption of any definite pathologic
change. The minimum quantity of thyroid and its more restricted distribution appear
to us as affording a more representative picture of the ultimate normal. Maurer, while
not mapping in detail the distribution in the adult, describes a condition which speaks
for the more confined arrangement of thyroid tissue (fig. 5 and 6).
EMBRYOLOGY.
Maurer (1886) has described the development of the thyroid in trout. According
to his observations, about the twenty-seventh day after fertilization, the embryo being
6 millimeters long, an unpaired median evagination arises from the ventral epithelium
of the pharynx (fig. 7). This is the earliest differentiation of thyroid. It lies in front
of the heart in the bifurcation of the heart tube into the hvoid arteries, and consists
CARCINOMA OP THE THYROID IN SALMONOID FISHES. 375
of several layers of cubical cells. At this time no cartilage is differentiated, but the
hyoid arch is well developed and the true gill arches are indicated, the brain vesicles
and mouth opening are present, while the only macroscopic vessels of the region are
the S-shaped heart tube and the two hyoid arteries.
The primary evagination lies close but not attached to the arterial wall, from which
it is separated by connective tissue. At 32 days it has become spherical, has a lumen
of its own, its epithelium is single layered and is connected with the mother cells only
by a slender pedicle. (Fig. 8.) At 35 days it has completely separated (fig. 9), is
about 0.04 millimeter in diameter, and lies exactly in the fork of the heart tube, which
is o.i millimeter in diameter before the bifurcation. The four pairs of true gill arteries
are now visible.
During the next six days the vesicle becomes somewhat elongated and changes its
position. It now measures about 0.03 by 0.06 millimeter and has been pressed back
of the bifurcation and lies ventral to the gill artery trunk, or ventral aorta (fig. 10).
Colloid is now present and the vesicle begins to put out buds which rapidly develop a
lumen filled with colloid and quickly separate. These multiplying buds grow around
the aorta to the dorsal side and keep pace with its increase in length until, at 77 days
or 3 weeks after hatching, that portion of the aortic trunk from the last branchial
arteries forward to the bifurcation is surrounded by thyroid follicles. Finally, thyroid
growth failing to keep pace with the lengthening of the ventral aorta, the adult con-
dition is approached when the thyroid mass breaks up into irregular deposits or clusters
of follicles which remain in the vicinity of the ventral aorta.
In the adult trout the greater portion of the thyroid is dorsal to the aorta. Maurer's
description therefore requires that it migrate, from its origin dorsal to the heart tube,
to the ventral side of the aorta and then back again to the dorsal side, and this view is
confirmed by our specimens.
While colloid no doubt appears very early in the embryo and before the latter
leaves the eggshell, Maurer's statement that it appears about the forty-first day of
incubation is indefinite, since incubation proceeds over a considerable range of tem-
perature and is much more rapid in the warmer water. The stage of incubation may
be accurately stated in temperature units when both time and temperature are known.
From the facts at hand, however, it may be expected that all normal trout embryos
have developed colloid as soon as the hatching stage is reached.
In our specimens of hatchery brook trout still in the sac stage, but some days
hatched, colloid is plainly visible (fig. 13) in many follicles. The amount and location
of thyroid tissue is even at this early stage subject to considerable variation. The
follicles are, however, always relatively few. In three examples the total number of
distinct follicles recognizable by serial sections throughout the floor of the mouth was
24, 27, and 33, respectively. In other cases there appears to be a smaller number. In
distribution two more or less distinct deposits are recognizable, besides scattered folli-
cles. One of these is at or in front of the level of the epithelial invagination which is
to become the jugular pit, a region which will be shown later to be the seat of thyroid
deposits in the adult. At this stage it is already a very definite infolding. The follicles
376 BULLETIN OF THE BUREAU OF FISHERIES.
are here in close relation to and not infrequently lie in actual contact with (fig. 10) the
cells of this imagination, and thus illustrate the probable origin of pit tumors. One
or more of the thyroid follicles can be easily dragged away from their neighbors with
the growth of the pit region and come to lie immediately beneath the pit epithelium,
as has been remarked in the discussion of distribution (fig. 14). When the thyroid
later proliferates abnormally, an independent tumor begins to occupy the jugular pit.
In the adult scarcely any thyroid is located so far forward as in these recently
hatched fry, where in the neighborhood of the pit it is to be found cephalad of the first
arch and of the bifurcation of the aorta. The other deposit or aggregation of follicles
centers in the region occupied by the adult thyroid, or in the vicinity of the second arch.
They are not arranged with any regularity, were not observed in any case to extend
laterally upon the gill arches but scatter along directly beneath the mesal bridge, and
reach in a few cases as far back as the beginning of the fourth arch. Between the
follicles about the jugular pit and those in the vicinity of the second arch, a gap usually
intervenes in which no thyroid occurs. The limits of variation in amount and position
of thyroid tissue can not be defined here, but from the material examined it appears
that either of the chief groups of follicles as just described may in some specimens be
entirely wanting, and that the adult gland may develop from one of these groups alone.
GROSS ANATOMY AND DISTRIBUTION IN THE ADULT BROOK TROUT.
While the thyroid is not a definite gland unit and on account of its small size, sepa-
ration into discrete aggregates, and lack of encapsulation can not be extirpated, or
dissected free in its entirety, it is nevertheless macroscopic in adult trout. On medi-
section of the floor of the mouth, delicate small masses of tissue may be seen about the
ventral aorta near the first and second arches between the vessel and the cartilages
and bone of the mesal bridge into which the gill arches unite. These masses contain
the chief aggregates of thyroid follicles, and consist in large part of connective tissue.
They are likely to be found close to the second gill arch, and more likely to lie opposite
the interspaces between the arches than opposite the arch itself. Under a hand or
dissecting lens the individual follicles may be recognized embedded in the mass. Only
the massed follicles are to be seen with the naked eye and therefore the outlying small
deposits are not demonstrable save on microscopic section. The macroscopic thyroid
masses in wild fish will only be found close to the middle line and at or just in front
of or behind the second arch. Such masses closely resemble in appearance the fatty
and areolar tissues which contain no thyroid, and can not be recognized with certainty
as thyroid without a lens.
The exact location of thyroid follicles in the adult is variable. Perhaps every fish
gives a recognizably distinct distribution pattern. To understand the location of the
thyroid some consideration of the anatomy of the skeletal and other parts of the floor
of the mouth is necessary. There are five pairs of branchial arches, of which only the
cephalic four bear gills. Each arch save the fifth is composed of several bones, of
which the ventral, or hypobranchial, is united with its fellow of the opposite side by the
mesal unpaired basibranchial, and by cartilaginous copulae which thus form the links
CARCINOMA OP THE THYROID IN SALMONOID FISHES. 377
between the right and left halves of each pair of arches. The basibranchials are con-
nected with each other by these same cartilaginous copulae, so that a solid mesal bridge
is formed on the floor of the mouth, continuous with the tongue and reaching back to
the fourth arch. The basibranchials lie opposite the interspaces between the arches,
while the copulae lie opposite the arches themselves. The first and second basibranchials
are well ossified, the third less so, and the fourth is mostly cartilage.
Immediately beneath this bridge runs the ventral aorta. The bulbous aorta is
located deeper, well beneath the floor of the mouth and somewhat back of the fourth
arch. From it the ventral aorta runs dorsocephalad to a point just under the third
arch. Here are given off the two trunks which soon bifurcate into the third and fourth
branchial arteries supplying the corresponding gills. Thence the ventral aorta runs
cephalad and slightly ventrad. Near the caudal margin of the second arch the second
pair of branchial arteries is given off, supplying the second pair of gill arches. Finally
the ventral aorta, just as it reaches the first arch, bifurcates into the first pair of branchial
arches. A certain amount of space is left about the ventral aorta between it and the
parts which inclose it. This space is greater dorsal to the vessel, and especially at the
origins of the first and second pairs of branchial arteries. It contains the normal thyroid
and its supporting tissues.
Figures 15 and 16 illustrate the lateral, longitudinal, and dorsoventral distribution
of normal thyroid. They represent the condition in no single fish, but show compositely
a probable average from a number of individuals. Two chief masses of thyroid may
usually be recognized, the follicles clustering at and back of the first and second pair of
branchial arteries, with usually a definite space between them in which but few and
scattered follicles occur. Occasionally three masses or groups are recognizable, and the
masses themselves present irregularities in the arrangement and number of follicles.
Exact medisections show less thyroid than those slightly sagittal on account of the
extension of the copulas and basibranchials to the aorta at the second and third arches
on the mesal line.
We have not found in the normal wild fish studied by us any lateral extension of thy-
roid structure along the branchial arches. Most of it, in fact, hardly reaches the lateral
margins of the mesal bridge. The most cephalic extensions rarely reach the first basi-
branchial, and on the mesal line scarcely to the first copula. The extreme caudal exten-
sion is to the fourth arch, but usually there are but few follicles either at or behind the
third pair of branchial arteries. Follicles are present in bone spaces, but in normal wild
trout we have never found them among the muscle bundles. They are frequently em-
bedded in the fatty tissue network or lie loosely attached to the vessels or other tissues,
but never show any invasive tendency, nor do the follicles occupy more than a part of
the apparently available space of the thyroid region.
ANOMALOUS DEPOSITS OF THYROID.
In a quantitative sense all the thyroid of importance is confined to the immediate
vicinity of a portion of the ventral aorta. As the thyroid is a somewhat diffuse organ
8207° 14 2
378 BULLETIN OF THE BUREAU OF FISHERIES.
one might expect to find instances of remotely placed deposits. We are therefore
surprised to find the sharp delimitation to the region already described which appears to
exist in our wild specimens, with one marked exception, i. e., the jugular pit to which
reference has already been made. It has been assumed by some writers that aberrant
thyroid deposits in some regions might be frequently expected. This has been due to
the development of tumor nodules in regions beyond the normal and usual seat of
distribution, such as the lower mouth parts and gill arch region. The only outlying
tumors of this sort which may be inferred with certainty to arise from original deposits
of thyroid are the so-called pit tumors.
In the adult trout there occurs on the ventral side of the head between the dentary
bones a median irregular depression or blind pit open to the exterior. It is the region
where the muscles between the dentaries and those of the branchiostegals become
common. The skin dips into its ramifications with many plications and infoldings.
It is an entirely superficial and exterior landmark, and though independent of and well
removed from the thyroid region in the adult, is of some importance in thyroid pathology,
since at an early stage it is in closely apposed relation to the thyroid region, and is the
occasional seat of detached thyroid follicles and of independent thyroid tumors. This
much branched and partitioned cavity may be designated as the jugular pit (fig. n).
It may be recognized at or soon after the hatching of the embryo. Normal thyroid
has been several times observed immediately beneath the pit epithelium in wild brook
trout (fig. 14), where its presence may be readily explained by the mechanics of devel-
opment of the parts (fig. 12). Since of 91 trout with tumors, 25 showed pit tumors, one
may conclude that more than one-quarter of all brook trout have normally some thyroid
follicles in the region of the pit.
Occasionally detached tumors develop in the gill arches. We have never actually
seen thyroid follicles on the free portions of the gill arches, and there is little embryo-
logical presumption in favor of such deposits, notwithstanding the relation of the gill
arches with the thyroid region. The tip of the lower jaw has even much less anatomical
relation to the thyroid region, rendering it an unlikely place for stray follicles. The
examination by serial sections of the tips of the lower jaws of about 25 trout failed to
show any thyroid here. The region is called into question as a seat of normal thyroid
deposit on account of the rare cases of a thyroid tumor occupying this site. The
actually observed occurrence of normal thyroid in the pit and the incidence of tumors
here make it extremely probable that no other extralimital deposits occur with any
frequency, else such would declare themselves in tumor formation.
HISTOLOGY.
A closed alveolus is the unit of the thyroid gland. These alveoli are apparently
independent of each other save as they are more or less bound together by the vascular
framework and connective tissue stroma. Their lumina have no connections with
each other and each alveolus independently discharges its secretion into the circulation.
Many alveoli are quite isolated from their kind and lie. loosely in the tissue, whether
connective, muscle, bone, cartilage, or fat. In the simplest adult condition (fig. 14-21)
CARCINOMA OF THE THYROID IN SAUMONOID FISHES. 379
they are typically spherical, subspherical, or slightly elongated, and consist of a single
layer of flattened epithelium, with a large lumen completely filled with homogeneous
colloid readily stainable by cytoplasmic stains. The cells of this epithelium are poly-
hedral, very flat, with very deeply staining slightly vesicular nuclei, lying parallel with
the longer dimensions of the cell. The nucleus is longer than wide, about as thick as the
short diameter of the cell, but its other dimensions are shorter than those of the cell.
In size, alveoli show wide variation, the smallest measuring as little as 0.02 millimeter, or
even less, in diameter. From these all sizes are to be found up to plainly macroscopic
follicles at least 0.75 millimeter across. Perhaps even larger ones occur. Most of the
alveoli of course fall well within these extremes. Only the largest are visible to the naked
eye.
There is thus a promptly recognizable similarity between the structure and appearance
of the thyroid unit in the trout and that of man and other mammals. The entire gland
in these groups is similarly comparable in location, function, and perhaps in size, though
it is impossible to weigh the trout thyroid and difficult to estimate its weight or bulk.
The chief difference between the gland in fish and mammals lies in the absence from the
fish thyroid of even a suggestion of a capsule, which in man is a definite and important
structure which completely delimits the thyroid from the neighboring tissues and
confines its units as a definite gland organ. The trout thyroid lies in the various tissues
beneath the floor of the mouth without any very definite interstitial tissue of its own.
For the normal structure of the thyroid we have examined trout taken from natural
waters of the country, such as streams and lakes in wild and unsettled regions. From
these it is apparent that there is no inconsiderable variation in the thyroids of adult fish
in their natural habitat. This variation certainly depends largely upon age and season,
is no doubt in part individual, and is in our opinion also a function of other causes among
which is the nature of the waters inhabited, whether shallow, rapidly flowing streams
or the more quiet and deeper lakes. These natural conditions react with the metabolism
of the fish.
The simplest condition of the thyroid, as described above, was seen in wild brook
trout taken in January from the Au Sable River in Michigan. (Fig. 17.) The same
species taken in June from streams in Wisconsin differ in showing somewhat higher
epithelium, which may be regarded as cuboidal. Our specimens from these two sources
show the simplest or lowest epithelium, in most cases flattened and never higher than
cuboidal. Specimens taken in May from a lake in Algonquin National Park, Ontario,
Canada, show a further advance. The epithelium is distinctly higher and the general
character of the thyroid picture seems to us to separate these fish from the other groups
of wild fish discussed above and to justify their consideration under the heading of
simple hyperplasia.
SIMPLE HYPERPLASIA AND COLLOID GOITER IN WILD AND
DOMESTICATED FISH.
The picture of the normal thyroid in the wild Salmonidae is extremely characteristic,
and although, as described, considerable variations are found in the size of the alveoli»
380 BULLETIN OP THE BUREAU OF FISHERIES.
there is but a very limited range of change in the epithelial cells. So characteristic is
this picture that it is possible to recognize the condition of simple hyperplasia of the
thyroid, although the exact relation of simple hyperplasia to the function of the organ
is not clear. We have encountered a condition of the thyroid in specimens of brook
trout taken from the Algonquin National Park in Ontario, Canada, where the change
is sufficiently marked to constitute, in our opinion, a condition of simple hyperplasia in
fish living under wild conditions. (Fig. 18.) The specimens were taken in the regular
course of angling on several days in Little Island Lake in the park. The picture pre-
sented by the thyroid of these fish is sufficiently characteristic to permit the description
of the thyroid of any one specimen to serve for the rest. As compared with the thyroid
structure of Wisconsin and Michigan wild brook trout, the alveoli lie more closely packed
and present much more the appearance of a definite organ than in the strictly normal
condition. The alveoli are of much more irregular shape, presenting irregular forms
and protrusions, smaller pouch-like additions to the typical spherical or oval alveolar
structure, and evidences of budding. The epithelium is high cuboidal, stains more
deeply, and the long axis of the deeply stained nucleus is usually perpendicular to the
circumference of the alveolus. The colloid is diminished in amount, many of the
smaller alveoli containing little or none. It stains less deeply than in the normal struc-
ture. There are evidences of hyperaemia in the stroma and the stroma is much richer
in small cells than in the normal. The total number of alveoli seems to be increased.
We have not seen any evidences of karyokinetic figures in the cells. The epithelium
never reaches the high columnar and bizarre shapes found in the early stages of car-
cinoma. The entire thyroid structure is more uniform in type.
Simple hyperplasia of the thyroid has been described by Marine and Lenhart (1910)
as occurring in fish obtained from Lake Erie. Pike and bass, according to these authors,
are commonly affected; sheepshead and herring more rarely. They also report an
example of spontaneous colloid goiter in the pike which they consider the terminal stage
of hyperplasia that has undergone resolution.
A simple hyperplasia of this type undoubtedly occurs in fish under domestication.
It is impossible to distinguish simple hyperplasia in fish hatcheries from the first stages
of carcinoma of the thyroid, a difficulty which is common to the diagnosis of all malignant
tumors. We have been fortunate in having for study at Craig Brook a variety of the
Salmonidae which possesses natural immunity to carcinoma of the thyroid. These fish
are the Scotch sea trout (Salmo trutta Linnaeus) . The original stock was obtained from
abroad as eggs, hatched in the hatchery, carried through its various troughs, and the
adult fish ultimately came to occupy the ponds lying in a position where they received
the water from ponds above, in which carcinoma of the thyroid in brook trout was
extremely prevalent. The facts bearing on the evidences of immunity in this connection
will be considered later. The eggs taken from these domesticated sea trout have been
again hatched in the hatchery, maintained in the outside smaller troughs, and we have
thus had an opportunity to study the offspring of the adult fish at various stages, as
well as the condition of the thyroid in the larger fish. We have never found macroscopic
evidence of even the earliest stages of carcinoma of the thyroid in the younger of these
CARCINOMA OF THE THYROID IN SALMONOID FISHES. 381
fish. The examination of specimens of the offspring of the older fish at the fingerling
stage reveals the thyroid of occasional specimens in a state of simple hyperplasia (fig.
20), perhaps slightly more marked than that found in the wild fish from Algonquin
Park. (P. 75.)
In these small fish the thyroid is not markedly increased in amount and is largely
localized about the great vessels, but occasional groups of alveoli are found somewhat
more widely removed from these structures than normal, and occasional small groups in
the infoldings of the cartilage or bone or between the muscle bundles. The alveoli are
not unusually large, the epithelium is high cuboidal and low columnar, the long axes of
the nuclei perpendicular to the circumference of the alveoli. Both protoplasm and
nucleus stain more deeply than normal. The colloid is diminished in amount and stains
less well than in the normal specimens. (See fig. 20, which may be compared with
a similar photograph at the same magnification of a Scotch sea trout from the same lot,
2050 A, fig. 19, in which the thyroid structure presents a characteristic normal appear-
ance, and both may be compared with a fish of similar size taken in the wild state from
the Au Sable River, Mich., fish 199 A, fig. 19, of which an illustration at similar magni-
fication is provided.) The thyroid gland of the adult Scotch sea trout, when viewed in
the light of the conditions found in the smaller fish, in which occasional examples show
simple hyperplasia and the larger proportion strictly normal thyroid tissue, reveals a
similar division in character of the thyroid in the adults. A larger proportion of the
adult Scotch sea trout presents strictly normal thyroid tissue. (Fig. 21.) There does
not appear to be an increased amount of thyroid for the size and age of these fish. The
minority of the fish, however, presents microscopically a condition of the thyroid which
may be spoken of as colloid goiter. (Fig. 22.) In them the alveoli are greatly increased
in size, the total amount of thyroid is also increased, the walls of the alveoli are very
thin, the epithelium pressed very flat, and the lumina compactly filled out with large
masses of colloid.
From a careful study of the Scotch sea trout, it is clear that although, as will be
shown later, they are almost perfectly immune to carcinoma of the thyroid, a certain
proportion of them are affected by a process of simple hyperplasia which terminates
by resolution in colloid goiter. It will be shown later that spontaneous recovery of
carcinoma of the thyroid in the Salmonidae produces an entirely different terminal
picture from that of colloid goiter. In the instance above described of the Scotch sea
trout, the transformation of hyperplasia into colloid goiter has been brought about by
a process which has been termed resolution. In carcinoma the disappearance of the
tumors in spontaneous recovery is brought about by a process of regression, a part of
which may be referred to as resolution; that is, the epithelium undergoes changes of
type, colloid reappears, but the bulk of the tumor literally retrogrades. Many of the
alveoli totally disappear and large areas are frequently removed so rapidly as to require
extensive repair by connective tissue. All of the characteristic appearances found in
regression of malignant mammalian tumors, such as the frequency of large areas of hem-
orrhage followed by repair, the formation of pseudogiant cells by coalescence of the
epithelium, great increase in the connective tissue stroma especially at the margins of
382 BULLETIN OF THE BUREAU OF FISHERIES.
the tumor, deposition of pigment and final clearing up of these phenomena with total
disappearance of the tumor, leaving only a small residue of approximately normal
functionating thyroid alveoli, presents a picture which can be readily distinguished from
the characteristic appearance of colloid goiter, as found in the Scotch sea trout. From
the evidences obtained from the fish from the Algonquin National Park, we are of the
opinion that trout in the wild state may also suffer from simple hyperplasia of the thyroid,
which also, no doubt, would terminate by resolution in colloid goiter, although we have
not been fortunate enough to secure such specimens from the wild state. As the majority
of the Scotch sea trout under the conditions we have studied present both in the small
fish and in the adults a preponderance of strictly normal thyroids, it is obvious that this
condition is not the direct result of domestication, the existence of simple hyperplasia
in wild fish making this deduction obvious.
Whether simple hyperplasia leading to colloid goiter in the Scotch sea trout is a
process with distinctive etiology, possibly the result of unusual physiological demand
upon the organ, or a greatly modified type of carcinoma of the thyroid occurring in
an immune species, can not at present be determined. The observation in one or two
of the older fish of red floors, and one or two reported tumors which we did not see,
may indicate that further material may be secured which will throw light upon this
question. For the present we would recognize a simple hyperplasia not associated etio-
logically with carcinoma of the thyroid.
PATHOLOGIC ANATOMY.
GROSS ANATOMY.
EARLIEST MACROSCOPIC EVIDENCE.
The first evidence of thyroid proliferation visible to the unaided eye is the so-called
red floor (fig. 23 and 23a). It is a faint reddening or flushing of the median area of the
floor of the mouth usually opposite to or in the neighborhood of the second gill arches.
It is caused by the increasing blood supply of the main thyroid deposit and by hyper-
emia of adjacent tissues, which show through the epithelium. Its first appearance is
sometimes a mere streak, more often a circular or irregular diffuse reddening. It usually
soon spreads more widely, reaching a little out on the arches and tending to spread
forward toward the first pair of arches, and is, of course, variable. At the angles between
the arches the color is often heightened and very distinct. The color picture illustrating
the red floor shows a well developed process scarcely prior to visible swelling, and not
the very earliest flush of hyperplasia. The color changes rapidly under examination
on account of the excitement of the fish due to removal from water and the vigorous
handling necessary. The red flush pales rapidly under these conditions and often almost
disappears in less than a minute, due to the inhibition of the circulation from nervous
shock, the area taking on a dirty gray color.
The red-floor stage is not sharply demarcated from the succeeding stages. It pro-
ceeds gradually and is succeeded by or merged with visible tumor formation, the color
persisting and spreading in various degrees over the subsequent swelling.
CARCINOMA OF THE THYROID IN SALMONOID FISHES. 383
Fish which are without any clinical evidence of thyroid disease, either in externally
visible swelling or the inflamed and flushed condition of the floor of the mouth, are for
brevity referred to in this report as clean or clinically clean.
It is the increased vascularity associated with increased thyroid that causes the
red floor, and an increased amount of hyperemic thyroid tissue of normal type sometimes
makes a visible flush on the floor of the mouth so that the red floor is not an absolute
and infallible sign of thyroid hyperplasia. The wild brook trout held in confinement
in cement tanks and fed natural food showed after two years a number of cases of red
floors. (See table vm.) Microscopically the thyroid was considerably increased in
amount but not otherwise definitely changed from the normal type. Likewise the
adult Scotch sea trout show occasional red floors referable to the microscopical condition
of colloid goiter. Such cases of red floors are evidently to be separated from those in
which the flush is caused by the early stage of carcinoma.
VISIBLE TUMORS.
Branchial junction. — Whereas evidence of beginning growth of thyroid tissue in
the affected fish is first shown by a more or less distinct reddening of the floor of the
mouth, the growth of tumor tissue in the spaces about the aorta and in the muscular
structure of the isthmus may proceed to a very considerable extent before the growth
gives other macroscopic evidence of its presence. The illustrations of visible tumors
in the literature usually depict growths appearing at the branchial junction. Because
of the resistance offered to the growth of the tumor by the bony and cartilaginous struc-
tures forming the floor of the mouth, it is natural to expect that the region at the junction
of the first pairs of gills with the isthmus, representing the line of least resistance, would
be the first and most frequent site of the visible outgrowths. This median region we
refer to as the branchial junction.
In an analysis of 91 tumors carefully classified (table i), we find that the branchial
junction alone is the site of the visible tumors in but 4 cases, but where the growth of
tumor tissue is sufficiently extended to protrude in other directions it is found to be the
site of visible outgrowths in combination with one or the other, in 67 cases. The branch-
ial junction is therefore one of the most common sites for the early evidence of tumor
growth. In many cases the first macroscopic evidence of the disease is found in the
appearance of small protrusions with smooth surface, of rose color, often not larger
than a grain of rice or smaller, on each side of the isthmus exactly at the branchial
junction. This evidence of tumor formation is almost always associated with the
evidences of reddening of the floor of the mouth and means that the available space
below the branchial arches and about the aorta is filled with tumor mass and that the
conditions favoring the growth downward of the tumor have determined its first pro-
trusion in this direction. Tumors making their first appearance at the branchial junction
on one or either side of the isthmus may rapidly develop into large growths in this region.
As they increase in size they become more readily recognizable, push the gill covers
apart and ultimately present themselves as obvious growths protruding into the gill
spaces on either side.
384 BULLETIN OF THE BUREAU OF FISHERIES.
In the diagrams of the 48 analyzed tumors here presented, great irregularity of out-
line, size and form of these outgrowths on the inferior aspect of the fish may be easily
studied. The freedom afforded by the spaces between the gill covers and the isthmus
permits of the growths of tumors of enormous size. Figure 27 represents a 2 -year-old
brook trout with a tumor of such magnitude that practically the entire gill space is
filled by one tumor mass, which has pushed the isthmus downward and practically oc-
cludes the entire gill space. In some cases tumors of great size may develop in such a
way as to push the isthmus to one side and present the appearance of a unilateral tumor.
In all these cases, however, the tumor tissue is found to extend from the median region
about the aorta, which is the site of the normal thyroid tissue from which all these
tumors spring. Occasionally tumors extend downward and make their first appearance
through the substance of the isthmus, indicating the exquisite infiltrative character
of the growth, and in one instance, the first macroscopic evidence of tumor (fig. 4) was
found at the base of the isthmus in the solid muscular structure of the breast of the fish.
Floor of the mouth. — Although the lines of least resistance for the growth of tumor
tissue springing from the thyroid region are obviously downward, a large proportion
of all tumors give evidence of their existence in the floor of the mouth. In an analysis
of 91 fish taken at random, visible evidence of tumor growth in the floor of the mouth
was found in 70 instances. The reddening of the floor of the mouth, which is the first
evidence of tumor growth, is replaced by infiltration through the structures of the floor
of the mouth, developing either by uniform bulging upward of the floor or the protrusions
of masses between the branchial junctions ; or one or more rounded masses of large dimen-
sion may become prominent. (Fig. 26 and 29.) Not infrequently, besides the upheaval
of the floor, the tumor tissue breaks through the elastic structure of the underlying
rnucosa and produces minute papillary growths. These are usually of shiny appear-
ance, small or rounded, irregularly shaped, and present the appearance of vegetations
scattered over the floor of the mouth. (Fig. 30.)
Pit tumors. — Early in our investigations Marsh called attention to the fact that the
jugular pit often contained a tumor which was entirely independent of the thyroid
enlargement originating in the thyroid region. (Fig. 24.) Of the 91 tumors analyzed,
in 5 the only macroscopic evidence of tumor growth was in the jugular pit. In combina-
tion with other regions the jugular pit was the site of tumor growth in 20 other examples,
and in the entire 91 it was the site of tumor growth in 25. As has been shown in the
chapter on embryology, we were able to demonstrate the existence of deposits of normal
thyroid tissue in the immediate vicinity of this so-called jugular pit. The frequency
of tumors in this region strongly indicates that deposits of thyroid in this region are not
uncommon, and in determining the limitation of distribution of the thyroid in normal
fish, the frequency of displacement of occasional follicles in this region must be recog-
nized. As will be seen from the diagrams, the jugular pit may be the site of outgrowth
of tumor tissue of very considerable extent, and of various forms. They are usually
subspherical, or hemispherical, may be slightly flattened or considerably elongated,
and occasionally vegetate irregularly and take on bizarre forms. They vary greatly in
size, from bare visibility to masses having a diameter of 17 millimeters or even more.
CARCINOMA OF THE THYROID IN SAL,MONOID FISHES.
t
385
DIAGRAM i.— Fish6i, S. fonlinalis, length 20 cm.; type alveolar.
DIAGRAM 2.— Fish 72, S. fontinalis, length 26.5 cm.; type alveolar.
DIAGRAM 3.— Fish 73, S. fontinalis, length 22 cm.; type alveolar.
DIAGRAM 4.— Fish 75-157, S. fontinalis, length 26.4 cm.; type tubular.
386
BULLETIN OF THE BUREAU OF FISHERIES.
I
DIAGRAM 5. — Fish 93. rainbow, length 38.5 cm.; type papillar.
DIAGRAM 6. — Fish 93, rainbow, length 39 cm.; type alveolar.
DIAGRAM 7. — Fish 94, rainbow, length 33 cm.; type papillar.
DIAGRAM 8. — Fish 96, S. fontinalis, length 25.3 cm.; type alveolar.
CARCINOMA OF THE THYROID IN SALMONOID FISHES. 387
DIAGRAM 9.— Fish 106, S. irideus, length 25.5; type alveolar.
DIAGRAM 10.— Fish 107, S. irideus. length 34 cm.; type alveolar
DIAGRAM u.— Fish 108. 5. irideus, length 34 cm.; type alveolar.
DIAGJIAM is.— Fish 116, S. solar sebago, length 10.3 cm.; type papillar.
388
BULLETIN OP THE BUREAU OF FISHERIES.
DIAGRAM 13. — Fish no, S. salar sebago, length 14.7 cm.; type alveolar.
DIAGRAM 14. — Fish 124, humpback, length 14. 7 cm.; type alveolar.
DIAGRAM 15. — Fish 135, humpback, length 14.8 cm.; type alveolar.
c±
DIAGRAM 16. — Fish 131, Coregonus, length 60 cm.; type sol'd.
CARCINOMA OF THE THYROID IN SAUtONOID FISHES. 389
DIAGRAM 17.— Fish 133, humpback, length 14.4001.; type alveolar.
DIAGRAM 18. — Fish 139, Salmo hybrid, length 10.7 cm.; type alveolar.
DIAGRAM 19.— Fish 140, Salmo hybrid, length 8.7 cm.; type solid.
DIAGRAM jo.— Fish 151. 5. fonti.nalis. length 11 cm.; type tubular.
390
BULLETIN OF THE BUREAU OF FISHERIES.
DIAGRAM 21. — Fish 152, S. fontinalis, length 19 cm.; type tubular.
DIAGRAM 22. — Fish 156, S. fontinalis, length 18 cm.; type tubular.
DIAGRAM 23. — Fish 172, S. fontinalis, length 17 cm.; type solid.
DIAGRAM 24. — Fish 174, S. fontinalis, length 20 cm.; type papillar.
CARCINOMA OF THE THYROID IN SALMONOID FISHES. 39!
DIAGRAM 35.— Fish 181, landlocked salmon, length 35 cm.; type alveolar.
DIAGRAM 26. — Fish 183, S. fonlinalis, length 15.9 cm.; type alveolar.
DIAGRAM 27. — Fish 205, hybrid, length 17.6 cm.; type papillar.
DIAGRAM 38.— Fish 208, hybrid, length 16 cm.; type papillar.
392
BUWJ3TIN OF THE BUREAU OF FISHERIES.
DIAGRAM 29. — Fish 209, hybrid, length 16.3 cm.; type papillar.
DIAGRAM 30. — Fish 217, S. fontinalis, length 9.9 on.; type alveolar.
DIAGRAM 31. — Fish 101, S. fontinalis, length 21.5 cm.; type papillar.
DIAGRAM 32. — Fish 117, S. solar sebago, length 14.5 cm.; type papillar.
CARCINOMA OF THE THYROID IN SALMONOID FISHES. 393
DIAGRAM 33.— Fish 121, O. gorbuscha, length 13.5 cm.; type solid.
DIAGRAM 34.— Fish 149, S. fontinalis, length 23 cm. ; type alveolar.
DIAGRAM 33.— Fish 160. S. fontinalis, length 21.9 cm.; type alveolar.
DIAGRAM 36.— Fish 175. S. fontinalis, length 14.5 cm- 1 type alveolar.
8207°— 14 3
394
BULLETIN OP THE BUREAU OF FISHERIES.
DIAGRAM 37. — Fish 100, S. fontinalis, length 24 cm.; type papillar.
DIAGRAM 38. — Fish 103, S. fontinalis, length 24 cm.; type papillar.
DIAGRAM 39. — Fish 122, humpback, length 14.5 cm.; type solid.
DIAGRAM 40. — Fish 112, S. salar sebago, length 13.5 cm.; type alveolar.
CARCINOMA OF THE THYROID IN SALMONOID FISHES.
395
DIAGRAM 41.— Fish 150, S. fonlinalis, length 16.5 cm.; type papillar.
DIAGRAM 42. — Fish 153, S. fontinalis, length 24.3 cm.; type alveolar.
DIAGRAM 43-— Fish 154, S. fontinalis, length 18.7 cm.; type alveolar.
DIAGRAM 44.— Fish 135. S. iontinalis, length 24 cm.; type alveolar.
396
BULLETIN OF THE BUREAU OF FISHERIES.
DIAGRAM 45. — Fish 158, 5. fontinalis, length 18.6 cm.; type alveolar.
DIAGRAM 46. — Fish 159, 5. fontinalis, length 21.6 cm.; type alveolar.
DIAGRAM 47. — Fish 162, S. fontinalis, length 23 cm.; type mixed.
DIAGRAM 48. — Fish 169, S. fontinalis, length 23 cm.; type alveolar.
CARCINOMA OF THE THYROID IN SALMONOID FISHES.
397
From their position they are subject to mechanical erosion on their ventral surface.
When well developed the tumor usually fills and completely obliterates the pit. When
the latter is not the seat of tumor growth, it is sometimes completely everted by the
pressure of the tumor from the main thyroid region, and almost all trace of it lost, the
surface of the skin being stretched smooth in this region.
TABLE I. — CLASSIFICATION OP VISIBLE TUMORS BY LOCATION.
Visible tumor presenting at —
Number.
Visible tumor presenting at —
Number.
Branchial junction
Pit and floor
Pit
Right gill region
Gill region and floor
Left gill region
i
Gill region and pit
Both gill regions
6
Pit, gill region, and floor
Floor .
Branchial junction and floor
6
Pit and branchial junction
Branchial junction and gill
4
Branchial junction, pit, floor
Gill region and floor
27
Pit and gill region
Visible tumors examined
HISTOLOGY.
EARLY STAGE.
Under "Simple Hyperplasia" we have presented evidence which we believe indicates
that there occurs in wild and domesticated fish a type of simple hyperplasia which leads
to colloid goiter. The first changes in the epithelium in any form of hyperplasia,
whether simple or malignant, would be of the same character and thus indistinguishable
one from the other. The progress of carcinoma of the thyroid in the vSalmonidae may
for convenience be divided into three periods: That in which only microscopic evidence
of hyperplasia is discernible ; the stage in which the growth of tissue extends sufficiently
to produce hyperasmic changes visible in the floor of the mouth — i. e., red floor; and then
the period of visible tumors. Histologically no line of demarcation is possible between
these various stages. Neither is it possible to distinguish the very first changes in the
epithelium at the onset of this disease from simple hyperplasia leading to colloid goiter
as we have observed it in the Scotch sea trout which have proven immune to carcinoma
of the thyroid.
Normal thyroid tissue in the Salmonidae is composed of isolated follicles lined with
flattened epithelium containing colloid. The follicles are distributed as shown about
the aorta in the loose connective tissue.
The first indication of the disease is found in the hypertrophy of individual cells ;
in a given follicle usually the change affects one or two adjacent follicles, or the only
evidence of the beginning of the disease is found in a small group of follicles lined with
cubical or columnar epithelium in which the colloid is greatly reduced or entirely absent.
Hyperemia of the vessels of the stroma is usually present. In our experiments with
wild Wisconsin brook trout, in which fish of varying size and age were taken from the
wilderness and placed in the waters of the Craig Brook hatchery, the first evidence of
398 BULLETIN OF THE BUREAU OF FISHERIES.
the disease was found in changes like those above described and affected individual or
small groups of follicles lying adjacent to the large arteries. (Fig. 40.) One or two
selected protocols of fish in which the disease was experimentally induced and properly
controlled show that the action of the agent causing the disease is clearly focal. Budding
of the wall of the follicle is early in evidence, presenting an appearance much like that
found in the embryo, where the formation of secondary follicles is in progress. But
here, instead of this budding, resulting in the formation of isolated follicles of the usual
type, we have the formation of irregular groups of cells, tubules, and groups of alveoli
of irregular shape, lined with columnar epithelium. In this way new follicles are formed
(fig. 36). From the very beginning there is a tendency to infiltration in the surrounding
structures. (Fig. 34.)
The fact that the gland of the teleost is not encapsulated was first offered by
Gudernatsch as an explanation for the infiltrative character of these growths. This is
undoubtedly true so far as the extension of formed follicles between the muscle bundles
and into the tissues adjacent to the normal deposits of thyroid tissue is concerned. In
this way, with the inauguration of the disease, we find the growth of thyroid tissue
into the surrounding structure. Such growth follows in the first instance the lines of
least resistance and is in our opinion quite distinct from the phenomenon of the infiltra-
tion of adjacent cell structures by individual cells — a phenomenon which is frequently
found with the very first evidence of the disease. The cells of the alveoli in this stage
have changed from flattened to high columnar, with deeply staining protoplasm, basilar
nuclei often vesicular and frequently with many karyokinetic figures. Where the follicles
have simply grown between the muscle bundles or against opposing structures, such as
bone and cartilage, they are frequently flattened, usually of small size, and closely
grouped. Where the follicles are broken through, and groups of individual cells infiltrate
the surrounding structures, there is frequently marked proliferation of the interstitial
connective tissue. Even in the early stages great variation in the arrangement of the
cells is apparent. They form long, narrow tubules, the alveoli more or less irregular
in shape, with solid masses of cells and large irregular spaces. The follicles may or may
not contain colloid. In the early stage there is generally a marked diminution in colloid.
(Fig- 36.)
RED-FLOOR STAGE.
In this stage the extent of proliferating thyroid is such as to be visible as a slight
flush on the floor of the mouth. Histologically the spaces surrounding the vessels
are filled with tumor tissue. Bone, cartilage, and muscle are invaded, and the tumor
tissue extends toward the gill arches and backward toward the heart. A characteristic
of this stage is that the tumor tissue does not seek the paths of least resistance, but
infiltrates in other directions. (Fig. 37.) The arrangement is tubular or alveolar in
most instances; the epithelium is high and deeply staining. Only occasional follicles
with colloid are encountered. There is a well-defined connective tissue reticulum.
Karyokinetic figures are numerous and are found in most tumors. (Fig. 35 and 36.)
CARCINOMA OF THE THYROID IN SALMONOID FISHES. 399
VISIBLE TUMOR STAGE — STRUCTURAL TYPES.
In the larger tumors one finds a remarkable variation in the histologic picture.
The fundamental types may be divided into four — alveolar, papillar, tubular, and solid.
In occasional tumors one of these three types definitely predominates. In the 100
tumors selected for study these types occur in the following proportions:
Types.
Per cent.
Fig. No.
Alveolar. . .
S6
Papillar
61
Solid
Tubular
•s
Mixed. . .
38
One is struck, however, in the study of these large infiltrating tumors, with the
remarkable variety of formation to be found in various regions. One may find in a
single tumor areas which may be placed under any one of the designations given. The
action of the stimulus upon the thyroid tissue in these tumors appears not only to work
irregularly, as will be shown by the advent of nodules of active proliferation and areas
simulating hyperplasia, but appears to throw the entire thyroid tissue into such a riot
of proliferation that a definite type for the entire tumor is seldom accomplished. The
epithelial cells forming the tumor present the greatest possible variety of form and size.
The nuclei are usually vesicular, in entire areas of a tumor the cells may present a typical
spindle form, thus simulating sarcoma, and in some instances areas of the tumor are
made up of a background of spindle cell tissue, through which are scattered small but
definite alveoli containing colloid. (Fig. 38.)
In such a tumor we have a picture analogous to the so-called mixed tumor of the
thyroid encountered in man. Occasionally tumors may be met in which a large propor-
tion of the tumor is made up of large alveoli packed with solid masses of large cells,
deeply staining protoplasm and vesicular nuclei, and frequent karyokinetic figures, pre-
senting the picture of proliferating struma. (Langhans.) (Fig. 39.)
Again, the general predominating type of a tumor may be distinctly papillary, in
which large vegetations covered with columnar epithelium and deeply stained nuclei
are found projecting into irregular spaces, usually free from colloid. The tendency
to papillary formation may be found in almost all of these tumors. Occasionally these
papilliform areas are of nodular form, in which case the cells forming the papillary nodule
are more deeply stained than the surrounding tubular or alveolar type, which gives
them a distinct focal character. (Fig. 45.) This marked tendency to focal or nodular
development within the tumors occasionally produces growths in which we have a large
mass of tubulo-alveolar structure, with nodules of solid, closely packed areas of intensive
proliferation. In figure 40 we have a low-power picture of such a tumor. The tumor
mass involves the entire area between the base of the tongue and the pericardial space and
extends between the arches to the floor of the mouth, where it projects in a series of
large protrusions, has pushed down the muscular structure of the isthmus, protrudes in
400 BULLETIN OF THE BUREAU OP FISHERIES.
the median line at the branchial junction and extends forward into the areolar tissue at
the base of the tongue, and presents visible evidence of erosion of the large mass of carti-
lage at the base of the tongue. The superior, anterior, and protruding posterior portions
of this tumor are composed of a network of large alveoli, free from colloid, in which are
embedded a number of dense nodular growths. One of these protrudes into the floor
of the mouth, a group of larger ones forms the central portion of the tumor, and one or
two small ones protrude into the anterior portion of the alveolar structure.
Here we have plainly a distinct focal evidence of proliferation of a much more
* intense type than that involving the surrounding alveolar tissue growth. The small
anterior nodule is found under high power to be composed almost exclusively (fig. 41)
of closely packed spindle and oval cells with deeply staining nuclei in which the merest
suggestion of an attempt at alveolar arrangement in some of the cell groups may be
traced. In the distinct nodule lying in the floor of the mouth the alveolar structure
is more apparent, and figure 42 shows a small, distinct nodule of adenomatous type.
The margins of these more or less solid nodules in this tumor gradually merge into
the loose alveolar structure forming the remainder of the tumor. In some tumors,
however, we have found small nodules of closely packed alveoli, the cells of which stain
deeply, with closely packed, deeply staining nuclei, the nodule embedded in a reticulum
of more open alveolar structure, the cells of which are not in so active a state of prolifera-
tion and do not stain so deeply. In many of these nodules expansive growth is evidenced
by compression and displacement of the alveoli of the tumor tissue surrounding the
nodule. (Fig. 43.)
INFILTRATION.
In another aspect of the nodule one finds definite evidence of infiltration of sur-
rounding thyroid tumor tissue by individual alveoli of the more malignant type. (Fig.
44.) We have here definite evidence of infiltration of thyroid tissue by a nodule of malig-
nant degeneration of more active type. The importance of this finding is that the
infiltration in this instance does not deal with anatomical landmarks or adjacent struc-
tures but represents a true infiltration, by a more malignant and rapidly growing portion
of the thyroid tissue, of surrounding thyroid structure.
A nodular development in the tumors indicates a more intense focal action of the
stimulus causing these tumors. It has been suggested that proliferation of the thyroid
in these growths in the Salmonidse is due to a reaction of the tissue to ^physiological
demands. A marked characteristic of physiological hyperplasia is the uniformity with
which the entire organ is affected. One of the most prominent characteristics of these
growths in the thyroid in the Salmonidae is intensive local stimulation, which leads not
only to nodules within the tumor masses, but gives the visible growth a marked lobulated
appearance. If these tumors represented a response to physiological demands, we
should expect a more uniform character of the hyperplastic tissue. We should expect
all of the thyroid tissue to be affected. In this connection the section of fish 158 is
significant. Here we have an extensive tumor (diagram 45, p. 36) involving the entire
region between the isthmus and the floor of the mouth, appearing at the branchial
CARCINOMA OF THE THYROID IN SALMONOID FISHES. 4OI
junction and in the gill spaces on both sides, protruding between the first and second
branchial arches, and penetrating the floor of the mouth in the median line at the junction
between the second and third branchial arches.
Microscopically, this extensive growth is found to infiltrate the surrounding struc-
tures, bone, cartilage, and muscle. It may be classified as alveolo-tubular type. In
many regions it presents a characteristic solid structure. Only in occasional areas do
a few follicles contain poorly staining colloid. In the region of the third branchial arch
is found a cross section of bone, in the lumen of which is a group of thyroid follicles of
strictly normal appearance. (Fig. 47.) The follicles are of the usual size filled with
homogeneously and deeply staining colloid, the epithelium is flattened, protoplasm
small in amount, the nuclei stain deeply and homogeneously. A study of the preceding
and succeeding serial sections fails to show any opening through the wall of bone. The
tumor tissue is in immediate contact with the shell of bone for a considerable extent of
its circumference, the remainder is covered with periosteum and dense connective tissue.
The significance of this finding is that here we have a large tumor of tubulo-alveolo-
solid type infiltrating the surrounding structures, while lying within the medullary
space of the bone structure and included in the tumor tissue is a deposit of normal
thyroid tissue which by its appearance, and the presence of deeply stainable colloid,
must be in physiological continuity with the metabolism of the fish. That the deposit
of normal thyroid within the bone has remained unaltered because it was protected from
an agent working from without by being inclosed within the bone is probable, but no less
important is the fact that it shows clearly that portions of the thyroid structure in the
Salmonidae may undergo malignant change, while other portions of the thyroid tissue
remain strictly normal in appearance and retain their physiological function until, it
may be said, as this tumor was very advanced, the last stages of the disease.
A great deal has been said about the significance of the capsule of the thyroid in
mammals. Here the evidence of malignancy consists in a breaking through the capsule
and infiltration of the surrounding structures. As the thyroid structure of the teleost
has no capsule, such a criterion can not be applied, and some have ascribed the infil-
trative characteristics of these tumors to the isolated character of the follicles and lack
of a delimiting capsule. One of the best evidences of malignancy in the mammalian
thyroid is the development of isolated nodules of malignant character within the struc-
ture of an enlarged thyroid, and here the evidence of infiltration has not to do with a
capsule, but the infiltration of surrounding thyroid structure. A determination of
exactly analogous conditions in our tumors indicates that we have in the proliferation
of the tumor tissue in the Salmonidae an expression of genuine malignancy.
Infiltration of bone and cartilage. — The growth of these extensive tumors naturally
leads to the erosion and destruction of cartilage and bone. The mere presence of
thyroid tissue within the bone spaces of the branchial arches is in itself of no signifi-
cance. Deposits of normal thyroid tissue are often encountered in the open spaces of
both bone and cartilage. The shape of the bony and cartilaginous structure in the
floor of the mouth in the teleost is frequently such that the thyroid tissue grows in
through small openings in the base of the arches. In many instances, however, we
402 BULLETIN OF THE BUREAU OF FISHERIES.
find total destruction of cartilage and bone and marked evidences of infiltration of the
bony and cartilaginous structures by individual cells and groups of cells. (Fig. 48
and 49.)
Infiltration of vessel -walls,, — Genuine infiltration of vessel walls will serve much the
same purpose as infiltration of the capsule in mammals, as deposits of thyroid tissue
within the media of the larger vessels has never been encountered. Figures 33 and
50 show a section of the aortic wall stained with orcein, in which the elastic lamellae
of the media are split up and spread out into the adjoining tumor mass as the result
of the penetration between the elastic lamellae of the alveoli of an infiltrating tumor.
The aortic wall at this point is reduced to about half the thickness of the uninfiltrated
remainder of the circumference. We have here genuine infiltration of the media of the
aorta.
Infiltration of muscle. — Besides the growth of the alveoli of tumors between the
muscle bundles (fig. 37) , we frequently encounter infiltration of individual muscles cells
by tumor cells. In these cases the sarcolemma sheath is broken through and we find
the isolated cells of the tumor displacing the muscle fiber. (Fig. 51.) The tumor tissue
in many instances has lost its alveolar structure, the cells being closely packed together
without definite form. There are many instances of genuine infiltration by individuals
or groups of cells in the muscle fibers.
Infiltration of the skin. — This is usually best observed in the floor of the mouth.
It has been suggested that the breaking through of tumor masses of the outer integu-
ment was due largely to pressure, that the epidermis became greatly thinned and ulti-
mately eroded. This is in many instances true where large masses of tumor protrude
into the floor of the mouth or where protuberant growths extend downward or outward.
In the floor of the mouth, however, we frequently find that the elastic structure of the
skin and the epithelial strata overlying it are punctured by small vegetations. Figures
31 and 32 show such growths. Frequently growths penetrating the floor of the mouth
will be found to have split up and destroyed the elastic structure of the epidermis without
any appreciable thinning whatsoever, the entire thickness of the elastic structure sud-
denly disintegrating without any evidence of stretching or thinning. (Fig. 46.) It
is therefore evident that besides expansive growth, carcinoma of the thyroid in the Sal-
monidae presents indisputable evidence of genuine infiltration, such as we encounter
in malignant growths in other species.
%
OTHER OBSERVATIONS.
In 1905, L. Pick published a comprehensive article entitled "Carcinoma of the
Thyroid in the Salmonidae, " with 15 illustrations. It is by all means the most important
publication on this subject dealing with the histology of these tumors. Pick's material
consisted of 10 brook trout obtained from a hatchery, we are led to believe, in the United
States. He illustrates five of these fish, one of which exhibited a large infiltrating
tumor involving the entire region below the floor of the mouth and the muscular struc-
ture of the isthmus (Pick, 1905, fig. i). Figure 3 shows a small tumor at the branchial
CARCINOMA OF THE THYROID IN SALMONOID FISHES. 403
junction. Figure 4, a view from above downward, shows a vegetating tumor in the
floor of the mouth. Figure 2 illustrates an isolated tumor in the jugular pit, and figure
5 a tumor in the jugular pit and one at the branchial junction.
Pick's paper is particularly excellent in the thoroughness with which he deals with
the histology of these tumors. In fish i, with the large infiltrating tumor in the floor
of the mouth, he recognizes the variegated character of the epithelial structure, distin-
guishing an adenomatous portion and a follicular portion, both of which he closely
describes. He points out the absence of any evidence of a capsule and describes fully
and accurately the infiltrating character of the tumor tissue. He notes the extension
of the tumor in the lymph spaces of the neighboring muscular fascia, which he describes
as being destroyed by the infiltration. Strands of tumor cells which widen into follicles
invade the lymph spaces of the adventitia of the aorta. He describes the invasion and
breaking up of the tendon of insertion of the muscle of the isthmus. The epithelium
of the tumor invades the loose submucous fatty tissue, and the spaces of the dense con-
nective tissue and the tunica propria of the mucosa of the floor of the mouth. Not only
are the softer tissues invaded, but he finds that both cartilage and bone are destroyed.
This is accomplished by the tumor surrounding the bone growing into the various infold-
ings of the branchial arches and the cavities of the bone, opening up the capsule of the
cartilage, and invasion of the cartilage tissue proper, infiltration between the periosteum
and the bone, thus leading to the death of fragments of bone and the formation of
sequestra which through the process of decalcification and fibrillation disintegrate.
In his description of fish 3 he shows, in figure 8, the invasion of the mucosa of the
floor of the mouth by papillary outgrowths which, in the instance illustrated, shows
the formation of small cystlike alveoli within the epithelium of the mucosa. In fish 5
he describes and in figure 9 illustrates the solid type of tumor; in figure 10 is shown
the polymorphic nature of the cells of this tumor. In fish 7 he describes portions of
tumor with large cystic alveoli, flattened single layer of epithelium and stainable colloid
(struma thyreoidea parenchymatosa colloides). In fish 8 the papillary type of growth
is described.
Pick concludes that these tumors are undoubtedly infiltrating epithelial neoplasms,
malignant epithelioma, or in the general sense of Orth's definition, carcinoma. He
points out that the diffuse deposit of thyroid tissue does not necessarily become diseased
in toto; in fact, that it is more often affected at various points, that the growths are
pluri-centric. He thinks that these centers of growth originate simultaneously or at
different times, that they may grow more or less uniformly and that in some cases
outlying extensions of thyroid tissue become involved, these facts explaining the remark-
able variety of form of the tumors, the directions in which they infiltrate, whether
upward into the floor of the mouth or laterally into the gill spaces, and the fact that they
may be bilaterally symmetrical or unsymmetrical.
He points out the absence of a capsule in any of the tumor fish. He recognizes
that several of his tumors have retained very definitely the thyroid structure and speaks
of these as presenting the character of parenchymatous struma, although in such tumors
the infiltrative character and destruction may be very great, these being tumors of
404 BULLETIN OF THE BUREAU OF FISHERIES.
homotypic character; and that in others the great variation in size of cells and marked
deviation from the organal type produce tumors of heterotypic character.
IMPLANTATIONS AND METASTASES.
i
It is obviously of the greatest importance in a neoplasm of the character of the
carcinoma of the thyroid in the Salmonidae to determine whether or not metastases
or possibly implantation may occur. Although infiltrative growth is and will always
remain one of the best evidences of malignancy, yet in the last analysis a true neoplasm
must present some evidence of metastasis formation or the development of implants.
The experimental study of cancer has placed a new significance upon the importance of
transplantability. Experimental results with mouse and rat tumors clearly indicate
that metastasis formation may be controlled or at least influenced by concomitant
immunity, and as the immune phenomena are more outspoken in the more virulent
types of cancer, it is not surprising that a neoplasm involving a vital organ like the
thyroid, through its early infiltrative growth involving vital structures, might prove
the determining factor in the early carrying off of the individual and thus the life of the
affected fish might not extend into the period in which metastasis formation more
frequently occurs.
The rarity of the occurrence of metastases in any given group of tumors may well be
expected. In such a case one or two instances may serve the purpose of definitely
fixing the nature of the neoplasm. The occurrence of metastasis in the thyroid carci-
nomata of fish is certainly rare. The circulation of the fish is not well adapted to the
transportation of cells. The region in which transported cells would most easily obtain
lodgment would be in the bifurcations of the vessels of the branchial arches, and it is a
common occurrence to find isolated growths well away from the median line on these
structures, but as deposits of thyroid tissue are located immediately about the aorta
many of these growths will be found to be simply outgrowths from the primary mass in
the median line. Some of them are, however, so widely displaced from the median mass
that they may be looked upon as regional metastases in which the transport of cells
would have to be accomplished through the lymph channels. It may be said that
growths in this region, however, are not competent to determine the question of true
metastasis formation from transport of cells. A region already referred to and one in
which the development of tumors is very frequent, occurring in not less than 25 per
cent of the studied cases, is the jugular pit. The explanation for these growths is,
however, found in the frequent presence of misplaced thyroid tissue. The origin of
these deposits has been clearly traced and adequately explained.
Early in our observations we noted that occasional growths upon the tip of the lower
jaw were to be seen. (Fig. 28.) This region in the fish is one peculiarly exposed to
injury. The fish confined in tanks almost certainly run into the sides of the tanks or
the screens and injure the epidermis at this point. These growths at the apex of the
lower jaw might be explained by the presence of unusual deposits of thyroid tissue at
this point. We have examined, by serial section, this region of the lower jaw in 25
fish, and have never found any trace of normal thyroid in this location. Furthermore,
CARCINOMA OP THE THYROID IN SALMONOID FISHES. 405
a careful study of the development of the thyroid in the embryo gives no indication
whatever of the likelihood of thyroid tissue being deposited at this point, and in the careful
survey of the distribution of the thyroid in wild fish we have never seen any deposits of
normal thyroid tissue even so far forward as the base of the tongue. We must, there-
fore, conclude that there is no evidence that thyroid tissue is ever laid down in this
locality.
The anatomical structure at this point is also very unfavorable for the deposit of
normal thyroid tissue. The symphysis of the dentaries here is covered only by the peri-
osteum, a thin layer of dense subcutaneous connective tissue upon which rests directly
the elastic structure and the epidermis of the outer covering. In fish 6 1, diagram i,
we find an extensive growth of thyroid tumor springing from the apex of the lower jaw,
entirely distinct and separate from the usual growth of tumor about the aorta and
extending up into the floor of the mouth. A microscopic examination of the growth of
the tip of the jaw and the primary growth in the substance of the isthmus shows that
they present much the same appearance, being both alveolar in type and many of the
alveoli containing stainable colloid. (Fig. 52 and 53.) The similarity in the primary
and the detached growth on the tip of the jaw naturally indicate that we have here to
deal with a metastasis.
There is, however, a further possibility, and this is that a growth has developed
from an implant finding lodgment upon the prepared site of an injury. We have fre-
quently observed that fish with large protruding tumors in the gill region attempt to
free themselves of the outgrowths by rubbing the tumor upon the bottom of the pond.
This is evidenced by the frequent observation of tumors which have been worn off in this
way. It is quite easy to conceive that fragments of such eroded tumors floating in
the water of the pond might find lodgment upon the injured apex of the lower jaw. If
this was the origin of this outgrowth on the tip of the lower jaw, the similarity between
the primary tumor and the secondary tumor would have to be a matter of coincidence.
We feel we may safely conclude that the growths on the tip of the lower jaw are true
metastases from primary growths in the usual locality, the lodgment of the cells by way
of the circulation being favored by reparative processes at this point, or that the growth
is a result of implantation through the medium of the water. From the standpoint
of determining the true neoplastic character of these tumors, the evidence would be in
either case of about equal value.
A case of still greater importance has to do with a 2-year-old brook trout from the
same source, in which a tumor measuring 7 by 8 by 14 millimeters, of pear shape, soft
consistency, and dark pinkish color, was found in the lowermost portion of the hind gut
or rectum just within the anus. (Fig. 25.) Careful examination shows that the tumor
is for the greater part covered by the mucosa of the intestine. It protrudes within the
intestinal canal, which is greatly flattened and pushed to one side, and has obviously
been obstructed by the tumor. (Fig. 54.) A section made from the wall of the intes-
tine, including the intestinal lumen, well into the tumor, presents on microscopic exam-
ination the following conditions :
406 BULLETIN OP THE BUREAU OF FISHERIES.
The tumor is of alveolo-tubular type, the greater proportion of it solid. It involves
the muscularis mucosa of the intestinal wall, bundles of muscles derived from this struc-
ture running through its substance. In the more open portions of the tumor, alveoli
containing colloid may be found. Under higher power (fig. 57) the epithelium of the
tumor both in the alveolar and tubular types consists of large cells generally of high
columnar type. The protoplasm is deeply stained; the nuclei are vesicular, of basilar
location. In some areas marked variation in size and character of the epithelial cells
is evident. Karyokinetic figures are not infrequent. The heterotypic nature of the
epithelial cells is best seen in the region where the muscular coat of the intestinal wall
is infiltrated. (Fig. 57.)
The larger proportion of the tumor is rather regular in formation, homotypic in
character. In many places the epithelium is so closely packed that scarcely any evidence
of alveolar structure may be made out. The relation of the intestinal lumen to the
tumor growth is of peculiar importance. Carefully scanning the tumor under low power
a point may be found where the intestinal epithelium spreads out into a single layer
upon the surface of the tumor. (Fig. 55.) There is no evidence of transition from the
intestinal epithelium into that of the tumor; in fact the marked columnar character
of the intestinal epithelium, with its frequent goblet cells, is clearly distinguished against
the background of tumor tissue. Upon the surface of the tumor the single layer of
epithelium from the intestinal papillae extends for a considerable distance upon the sur-
face of the tumor, the uppermost portion of which is, however, eroded. Evidences
of occasional hemorrhages upon the surface may be found, the apex of the tumor being
covered with a distinct clot. In other portions of the tumor the characteristic appear-
ance of alveoli of irregular shape generally filled with colloid is to be found and in this
region the tendency to papillary growths within the alveoli is quite distinct. (Fig.
56.) In this region also the structure of the muscularis mucosa is apparent, and the
marked infiltrative character of the tumor is here distinctly evident.
The histologic diagnosis of this tumor is to our mind quite clear, It consists of
thyroid tissue presenting the characteristics of the alveolo-tubular type of tumor of the
thyroid in the Salmonidae. It furthermore presents in certain areas that tendency to
papillary formation which is so frequent in these tumors. The histological picture
and the presence of colloid quite clearly determine the nature of this growth. It is
greatly to be regretted that through an unforeseen accident the thyroid region of this
fish was not preserved. We have no evidence as to the nature of the primary growth
in the thyroid region. Although the fish presented no macroscopic evidence of tumor,
yet there is little doubt that a primary tumor in the thyroid region existed. The fish
was taken from a hatchery in which one of the most outspoken epidemics of the disease
we have yet encountered was in full progress. As all of the brook trout of this age
succumbed to the disease in the course of two seasons, and as every specimen taken
from the pond in which this fish was found presented macroscopic or microscopic evidence
of the disease, there is little reason to doubt that we have here to deal with a metastasis
from a tumor originating in the thyroid tissue of this fish.
CARCINOMA OP THE THYROID IN SAUfONOID FISHES. 407
We have expressed our reason for holding that the growths on the apex of the
jaw and this growth in the wall of the intestinal tract just within the anus are instances
of genuine metastasis formation. We believe that a wider understanding of the natural
history of carcinoma of the thyroid of the Salmonidae will show that a case described
by Marine and Lenhart (191 la, p. 470) is more probably a metastasis than a tumor
springing from misplaced thyroid. These authors describe an abdominal goiter in a
29-months-old fish. The thyroid mass was round, circumscribed, and measured one by
one-half cubic centimeter, was attached to the cardiac end of the stomach by a connective
tissue pedicle and extended into the abdominal cavity. The fish had a large ventral
tumor histologically identical with the abdominal growth. Because an examination
of the visceral regions showed no such deposits of thyroid tissue, these authors looked
upon this specimen as an enlarged aberrant thyroid deposit. They also report having
seen growths on the tip of the lower jaw in from 2 to 3 per cent of all fish with visible
tumors examined by them, and these they also hold to have sprung from misplaced
thyroid deposits.
COMPARATIVE PATHOLOGY.
The study of hyperplasia and carcinoma of the thyroid in the Salmonidae, on account
of the great similarity in the changes in the organ of the fish to that occurring in mam-
mals, seems likely to throw important light upon the origin of certain structures which
have been the subject of extensive study in the thyroid of mammals. Virchow (1863),
Wolfler (1883), Hitzig (1894), and Michaud (1906) have described in the thyroid of
man small adenomata, the condition being known as struma nodosa. Virchow held
that these nodules developed by proliferation from the follicles of the thyroid. Wolfler
held that they developed from misplaced embryonic rests. Hitzig evidently opposed
the theory of Wolfler as to the embryonic origin of these nodules and held that they
developed by proliferation from the normal tissue of the thyroid, for the reason that
in normal thyroids they were never found. Michaud has carefully studied the genesis
of these adenomata and agrees with Virchow and Hitzig that they are formed by pro-
liferation from normal structures of the thyroid.
According to Michaud these growths develop by changes in the epithelium of
normal follicles, which take on columnar type and through proliferation of the cells form
extensions and protrusion of the follicles and finally by budding produce new follicles
which become detached from the original. The first changes, which are focal, are
restricted by the surrounding stroma, which takes no part in the change. From this
point on the nodule grows by proliferation of the structures within it, especially those
toward the center. The very first evidence of this change is found by Michaud in the
presence in the thyroid structure of long, tortuous clefts or tubes with cubical or colum-
nar epithelium, staining more deeply than the surrounding structures, these tubules
having already been noted and described by Hitzig. From these tubules, by the process
of budding above described, are developed focal nodules, i. e., struma nodosa.
It will be seen that the description given by Hitzig and Michaud for the development
of these isolated adenomata in the mammalian thyroid is exactly like the beginning
408 BULLETIN OF THE BUREAU OF FISHERIES.
changes leading to carcinoma of the thyroid in the Salmonidae as we have described it.
Tn figure 84 the change from flattened to columnar type, with deeply staining protoplasm,
lengthening and flattening of the tubules, closely resemble those found in the mam-
malian thyroid by Hitzig and Michaud, and, with the exception of the hyperaemia,
which is associated with the more intensive chnges, in the hyperplasia of the thyroid in
the Salmonidae. The advent of isolated nodular growths, sometimes sharply circum-
scribed (fig. 45), indicates that focal proliferation of the thyroid tissue in the fish fre-
quently leads to the development of nodules presenting the picture of nodular struma
in mammals. The structure of the normal thyroid in the Salmonidse is so simple and its
amount so limited, that a careful study of this structure in all age periods of the fish
renders it clear that the advent of tubular structures with columnar epithelium clearly
represents a pathological change, and here we are not troubled with the many questions
which arise to complicate the study of these structures in the mammalian thyroid. We
can, in the thyroid of the Salmonidae, definitely exclude the idea voiced by Kramer, 1910,
that such tubules in the mammalian thyroid were probably originally the remnants
of execretory ducts persisting from an earlier period of development of the mammalian
thyroid. It is plainly evident from the study of the normal thyroid in the Salmonidae
and the genesis of hyperplasia, nodular growths and fully developed carcinoma, that the
changes in this organ are brought about by the action of some agent working focally
upon the epithelium of normal vesicles, and we can clearly exclude all possibility of
embryonic rests playing a part in the genesis of circumscribed adenomata or cancer.
The evidence adduced on this subject therefore confirms, so far as the evidence is
applicable, the conclusions of Virchow, Hitzig, and Michaud that struma nodosa develops
as the result of focal change in the epithelium of normal structures of the thyroid. The
production of tubules and irregularly distorted spaces lined with columnar epithelium
and the process of development of new follicles by budding, as described and illustrated
by Michaud, are repeatedly encountered in our specimens, especially in the earliest stages.
(Fig. 36.) The theory that carcinoma of the thyroid develops especially from the
adenomata of nodular struma and that endemic goiter is the result of a physiological
hyperplasia of normal thyroid tissue, finds no support in our study of carcinoma of the
thyroid in the Salmonidae. The theory of Marine that iodine affects alone physiological
hyperplastic changes of the thyroid tissue and does not affect these adenomata, and may
thus be used as a means of distinguishing between physiological hyperplasia and cancer,
is obviously untenable, as we find that iodine, as well as mercury and arsenic, affect
not only fully developed carcinoma of the thyroid but where tumors contain individual
adenomata these are likewise affected. Well-developed tumors in the Salmonidse some-
times closely simulate the structures of nodular struma in the mammal. Figure 65
represents such a tumor and may be compared with figure 66, struma nodosa in man.
The tumors of the fish frequently contain the so-called Wachstum centra of Aschoff .
(Fig. 66.)
Although it may not be wise to go too far in the comparison of carcinoma in the
Salmonidae with carcinoma of the thyroid in mammals, yet inasmuch as we will show
CARCINOMA OP TH6 THYROID IN SAI^MONOID PISHES. 409
later that at least the first stages of this disease can be induced in mammals through the
drinking water, such a comparison at the present time becomes even more profitable
than formerly. The final relation of these tumors to tumors in mammals can now be left
to experimental investigation; especially the production in mammals of metastasizing
tumors would serve to clear up the possible relation between carcinoma of the thyroid
in the Salmonidae and carcinoma of the thyroid in mammals. For the present we con-
sider that we have more firmly established the fact already assumed by Plehn, Pick,
and many other investigators, that we are here dealing with carcinoma of the thyroid
in fish.
Pick, in his excellent article, after having established the homotypic and hetero-
typic character of these tumors, compared them with the malignant epithelial tumors of
other animals, especially carcinoma of the breast in mice. This analogy of Pick's is well
taken and we feel that the progress of experimental cancer research has since demonstra-
ted many other points of analogy, which we shall deal with later. Pick also pointed out
that certain degenerative and regressive changes are common both to carcinoma of the
thyroid in fish and the epitheliomata of mammals. The impossibility of classifying
the different types of carcinoma of the thyroid in fish affords another point of similarity
with carcinoma of the breast in mice, where the greatest variety of histological appear-
ance may be found in the same tumor. A still closer analogy, according to Pick, is to
be found in the histological character of the growths of the thyroid in fish when compared
with similar tumors in man, although from the material at Pick's disposal he had no
evidence of metastasis formation, such as we are now able to bring.
One of the most important contributions to our knowledge of the various types of
epithelial proliferation of the thyroid structure in man is found in a monograph, based
on very extensive material, entitled "On the Epithelial Forms of Malignant Struma, "
by Langhans (1907), in which this author classifies the various types of malignant
growths of the thyroid in man under the following heads :
1. Proliferating struma.
2. Carcinomatous struma, the usual irregular structure of carcinoma.
3. Metastasizing struma.
4. Para struma.
5. Small alveolar, large-celled struma.
6. Malignant papilloma.
7. Squamous epithelioma.
From a comparison of our material with that of Langhans we find that in the fish
tumors, areas of proliferation, or in some instances the greater part of the structure
of a tumor, may be said to conform to one of three of the six types described by Lang-
hans for man, namely, proliferating struma, carcinomatous struma, and malignant
papilloma. Figure 59 illustrates a tumor in which the preponderating type is almost
identical in appearance with the type described by Langhans for proliferating struma and
may be compared with figure 60, made at the same magnification from one of Prof.
8207 ° — 14 4
410 BULLETIN OF THE BUREAU OF FISHERIES.
Langhans's original sections which he was kind enough to transmit to us. Carcinoma-
tous struma in man has its analogy in many of the illustrations of fish tumors given.
Figure 63 illustrates the papillary type of carcinoma in the Salmonidae, which may
be compared with figure 27, plate 6, of Langhans's article, illustrating the type known
as struma of Geisslar. Langhans's group 6, malignant papilloma, finds its counter-
part in many of the fish carcinomata, papillomatous areas occurring in almost all tumors.
Figure 61 illustrates a tumor of almost pure papillomatous type and may be compared
with figure 62 from one of Prof. Langhans's sections of malignant papilloma in man and
illustrated by him as figure 32, plate 7, of his monograph.
Pick was of the opinion from his material that carcinoma of the thyroid in the
Salmonidae was a condition superimposed upon endemic goiter and referred to the
occasional observation of malignant growths in man upon the basis of preexisting
nonmalignant struma. He suggested that endemic goiter might be distinct from, but
was the predisposing factor in, carcinoma of the thyroid in fish.
There is no point at which it is possible for us to draw a line between what might
be called endemic goiter in the salmonoid fishes and carcinoma of the thyroid. Which-
ever interpretation one may desire to put upon this process, endemic goiter and carci-
noma of the thyroid in the Salmonidae are one and the same thing. Viewed in the light
of modern cancer research, it appears to us that the term carcinoma is in every respect
the more suitable. The first positive results obtained by us in dogs and rats must, for
the present, be classed as diffused parenchymatous struma; but as Bircher has already
produced nodular struma in his rats, and it is well known that such adenomata of the
thyroid develop into what is called cancer of the thyroid, it appears to us quite possible
that further experiments may show that in mammals experimental parenchymatous
and nodular struma are but the early stages of the process which is called cancer of the
thyroid.0
o At the meeting of the Freiburger medizinische Gesellschaft June 3, 1912, Prof. Aschoff demonstrated certain preparations
of fish and dog thyroids which had been transmitted to him by us. The report of this meeting in the Deutsche Medizinische
Wochenschrift, no. 25, June 20, 1912, contains certain inaccuracies. Prof. Aschoff is reported as stating that Marine and Lenhart
were the first to produce struma in fish experimentally, and spoke of our work as a repetition of such experiments. In none of
the publications of Marine and Lenhart is such a. claim made. We do not know of any investigators having had the facilities or
opportunity to carry out experiments of the kind detailed in this report, requiring, as they do, wild fish taken from regions free
from the disease and introducing them into a hatchery under conditions with proper controls to demonstrate that they have
acquired the disease. As this incorrect report has been quoted by Schittenhelm and Weichardt in their monograph on endemic
goiter in Bavaria, it seems desirable to make this statement.
In their quotation of Prof. Aschoff's remarks these authors state that Aschoff emphasized the similarity of our tumors
in fish with the pathological findings in Basedow's disease in man, and that he could not support our view that the fish
struma was carcinoma. From the protocol of the meeting quoted it does not appear that he expressed himself so positively as
this. He demonstrated the similarity of the preparations with Basedow's disease in man, but this must have applied to the
sections of the thyroid enlargement in dogs, and not the fish tumors. This report quoted the fact that iodine, as shown by
Marine and I^enhart and confirmed by us, when added to the water, influenced the fish tumors, this fact appearing to be
opposed to our interpretation that the fish tumors were cancer, and it did not emphasize the fact that sublimate and arsenic
produced the same result, as opposed to this interpretation.
In this connection we would state that in March, 1913, Prof. Aschoff spent a day at our institute in Buffalo, and after
carefully studying all of the preparations upon which this monograph is based, including the specimens of metastases, stated
that he now holds, in accord with us, that the tumors of the thyroid in the Salmonidae are carcinoma.
CARCINOMA OF THE THYROID IN SALMONOID FISHES. 4! I
OCCURRENCE OF THE DISEASE UNDER WILD CONDITIONS.
It is through the domestication of trout that attention was first attracted to thyroid
disease in fish, and it is from this source that nearly all material and data have been
derived, both in this country and in Europe. Nevertheless, the same thyroid process
has been identified with certainty among adult fish living in open natural waters.
The most important example of the kind at hand is a whitefish from Lake Keuka,
N. Y. This fish, of which the head alone came to our hands, is a member of the genus
Coregonus of the Salmonidae and belongs probably to the common species of whitefish
of Lake Keuka, Coregonus clupeiformis . (Fig. 67.) It was reported as about 60
centimeters in length, probably a female, though the sex was not definitely determined,
was caught December 3, 1909, in water about 15 meters deep, and was preserved in
formalin about two days later. The tumor, which is described in detail below, is of good
size and shows the typical structure common to this growth in the other salmonoid
species considered.
From the museum of the University of Buffalo has come to us a brook trout (S.
fontinalis} having a large thyroid tumor. (Fig. 69.) The fish (diagram 23, p. 30) is a
female 17 centimeters in length and was caught by Prof. Herbert M. Hill in 1902 from
Hosmers Creek, near Sardinia, Erie County, N. Y. About 3 miles of this stream con-
stituted a fishing preserve of the nature of a wild stream. It had for several years
prior to this time been stocked with 5,000 to 10,000 fingerling trout, all obtained from
the New York State Hatchery at Caledonia, N. Y. Some fry of the same species were
also obtained from the same source and were kept in a pond adjacent to the creek
where they were reared to fingerling size and then liberated in the creek. No artificial
feeding of any kind was done in the stream and the fish in question was either planted as a
fingerling, or possibly as fry from the Caledonia hatchery, or was possibly a descendent
of some few wild fish which occupied the stream before systematic stocking was com-
menced. It is more probable that the fish was originally a fingerling sent from Cale-
donia. From its size it was probably not under 2 years of age.
The tumor occurring in the wild living whitefish is found on inspection to pro-
trude in both gill spaces and between the first and second gill arches in the floor of
the mouth. It infiltrates the structures below the floor of the mouth beneath the
first and second branchial arches. (See diagram 16, p. 28, and fig. 67.) Under the
microscope the tumor presents areas of vesicular type. The alveoli are small, but
few of them contain stainable colloid. The bulk of the tumor is made up of areas of
closely packed deeply staining islands of cells, presenting the merest suggestion of alveolar
structure. The cells are closely packed, the nuclei vesicular, the protoplasm deeply
staining. Throughout the tumor there are evidences of karyorrhexis. The tissue
presents the appearance of not having been freshly preserved, but the histological
characteristics are sufficiently discernible. The nuclei are vesicular, and nucleoli
and karyokinetic figures are quite frequent. In some areas the cells are so closely
packed as to present the appearance of spindle-celled tissue. The whole presents the
characteristic picture of small alveolar carcinoma. The infiltrative characteristics
412 BULLETIN OF THE BUREAU OF FISHERIES.
are best observed in the wall of the large vein, where we find the cells in small groups
slightly suggesting an alveolar structure where they have penetrated into the media
of the venous wall. Shrinkage owing to fixation accentuates the chopped out
appearance of the media. (Fig. 68.) In studying the various sections in which this
vein is included one finds a point at which the venous wall is greatly thinned, and at
this point extensive hemorrhage into the surrounding tumor structure has occurred.
In the same section groups of tumor cells are to be found in the venous lumen. (Fig.
69.) We have here penetration of vessel walls by the tumor cells. Unfortunately,
owing to the fact that we had only the head of this specimen to study, we do not know
whether the viscera contained metastases or not.
In the brook trout from Hosmers Creek, N. Y. (diagram 23, p. 30), the tumor pre-
sents itself in the gill spaces on both sides of the isthmus, on one side shaping itself into
a mass the size of a hazelnut. Protrusion in the floor of the mouth is visible between
the first and second gill arches on the side of the large tumor and in the median section
it infiltrates the region below the first and second gill arches. The fish is preserved
in alcohol. Fixation is moderately good. The section of the tumor measures 1 1 by
9 mm. On macroscopic inspection of the section a deeply staining, sharply defined
nodule measuring 6 by 8 mm. is clearly discernible embedded in a more lightly staining
tumor mass. Inspection under low power shows that there is a distinct difference in
the appearance of the surrounding tumor and the nodule, the nodule being separated
from the tumor by a well-defined compression capsule. (Fig. 70.) The outlying
portions of the tumor are for the greater part composed of small alveoli, somewhat
loosely arranged, with occasional larger alveoli of irregular shape and marked columnar
epithelium. Wide venous channels are frequent in this portion of the tumor. Within
the capsule of the above-described nodule one finds the whole made up of somewhat
loosely arranged islands, strands, and masses of cells. The central portion of the
nodule presents wide venous sinuses without delimiting intima and areas, which are
no doubt the result of hemorrhage. Under high power one finds the cells in certain
portions of the nodule to be so arranged as to suggest small alveoli, but for the greater
part, especially in the well-preserved marginal portions of the nodule, the cells present
a distinct spindle character, and great variability in size of the nuclei, which are vesicular
with one or two nucleoli. The protoplasm of the cells stains deeply, is rather sparse,
and karyokinetic figures are very numerous. Certain areas may be found in which
the spindle character of the cells is so pronounced as to suggest the diagnosis of spindle-
celled sarcoma. (Fig. 71.) Gradual transitions of such areas into an arrangement of
cells clearly showing their derivation from the poorly formed alveoli indicate their
character. We have here a nodule of malignant tumor growth in a mass of tumor
tissue of less malignant appearance, carcinoma solidum simulating spindle-celled
sarcoma.
In June, 1913, a large landlocked salmon (S. sebago) with a large thyroid tumor
was caught in Sebago Lake, Me., by Dr. Charles F. Parker, of North Windham, Me.
Dr. Parker recognized the nature of the growth and forwarded it to us through Dr. W. C.
Kendall, of the Bureau of Fisheries. The fish was about 4 years of age, measured 23
CARCINOMA OF THE THYROID IN SA^MONOID FISHES. 413
inches in length and in its rather emaciated condition weighed 4 pounds. A salmon of
this length in health should weigh 6 to 8 pounds. A large thyroid tumor involved the
whole gill region, vegetating in the floor of the mouth and presenting on the ventral
surface several cystic lobes which kept the gills and gill covers well distended. (Fig. 72,)
Sebago Lake is located in the southwestern part of Maine. It has an area of about
45 square miles and a general depth of 316 feet. It has but few shoal places, the depth
of water often reaching close to the shores, which are for the most part rocky, save in
a few shallow coves. The lake has little aquatic vegetation; the water is regarded
as unquestionably pure and is the source of supply for the city of Portland. While the
fish had been living in a wild state for two or three years, it was originally planted from
a fish hatchery, where it may have contracted the disease. Microscopic inspection
of this tumor (see fig. 75) shows it to be almost entirely of the alveolar type, showing
at the center areas of cystic colloid degeneration.
These four tumor-bearing fish were living under wild natural conditions when
taken. All can be related more or less remotely to fish culture. They were taken from
waters in inhabited regions, in which fish culture has been practiced for years, and these
waters had frequently received the products of hatcheries. The trout inhabited a stocked
stream, and was possibly the product of a hatchery and fed artificially, or was descended
from fish so treated. The landlocked salmon was probably planted from a hatchery. No
whitefish are fed artificially nor reared to maturity in domestication. The product of
their artificial propagation is planted soon after hatching. The most that may be said,
therefore, as far as the relation of this tumor-bearing whitefish to domestication is con-
cerned, is that it may have been artificially hatched, planted before feeding, and was
living in a large lake which received the drainage from a large trout hatchery and breed-
ing establishment at which the thyroid disease was endemic and epidemic. It was taken
within 5 miles of the point of entry of this drainage inflow.
In one of the small lakes of the Adirondack Mountains of New York, which have
been stocked with trout from hatcheries, anglers occasionally report the taking of fish
with visible tumors at the throat.
In Europe Hofer (1904, p. 194) reports the disease in wild lake trout (Trutta lacus-
tris) living in the Mondsee. Dr. Plehn informs us that occasionally trout with thyroid
tumors and living under wild conditions in the streams of Bavaria are sent to the
Bavarian Fisheries Biological Station for examination.
OCCURRENCE AND COURSE OF THE DISEASE UNDER DOMESTICATION
DISTRIBUTION OF THE DISEASE IN UNITED STATES HATCHERIES.
The thyroid tumor among fishes is undoubtedly of wide distribution. We believe
it occurs almost universally where trout are made the subject of artificial propagation
and rearing under the ordinary conditions of fish culture in the United States. A
complete canvass of all the trout-breeding establishments in the country has not yet
been made, but such an investigation would beyond question indicate the distribution
of the disease as coextensive with trout culture. The following list gives the places
BULLETIN OF THE BUREAU OF FISHERIES.
at which, from an adequate examination of material, the disease is definitely known
to exist or to have existed in an advanced stage as expressed by the exhibition of visible
tumors.
District of Columbia.
Iowa: Manchester.
Maine: Craig Brook, Auburn.
Michigan: Paris; North ville.
Missouri: Neosho.
Montana: Bozeman.
New Hampshire: Nashua.
New York: Bath; Margaretville
hatcheries.
and other
Pennsylvania: Spruce Creek; Glen Eyre.
South Dakota: Spearfish.
Virginia: Wythe ville.
Vermont: Roxbury; St. Johnsbury.
Washington: North Yakima.
West Virginia: White Sulphur Springs.
NAMES OF SPECIES AND HYBRIDS.
While the disease primarily and chiefly is found in the brook trout, it has been
observed among all the following species and hybrids in the United States. Two of
these, the brown trout and Loch Leven trout, are introduced species, and one — the
whitefish — belonging to a subfamily of the Salmonidae, is not the subject of fish culture
as an adult and is represented by only one specimen bearing a tumor, this being a wild
fish from a lake. It is quite certain that this list will be much extended as fast as other
species of salmonoids are brought under domestication. The single species which,
though bred artificially, can not yet be included among the species subject to thyroid
carcinoma, is the sea trout (Salmo trutta Linnaeus), introduced into the United States
as the Scotch sea trout.
American brook trout; square-tail trout; redspot trout;
speckled trout Salvelinus fontinalis (Mitchill).
Rainbow trout Salmo irideus Gibbons.
Landlocked salmon; Sebago salmon; Schoodic salmon Salmo sebago Girard.
Loch Leven trout Salmo levensis Walker.
Brown trout; von Behr trout Salmo fario Linnaeus.
Atlantic salmon Salmo salar Linnaeus.
Great Lakes trout; lake trout; MackinaAv trout; namaycush
trout; longe; lunge; togue; laker Cristivomer namaycush (Walbaum).
Humpback salmon. Oncorhynchus gorbuscha (Walbaum).
Common whitefish Coregonus clupeiformis (Mitchill).
Hybrid salmon:
Female silver salmon \
Male humpback salmon . . . J
Female silver salmon 1
Male chinook salmon f
Female blueback salmon. .1
Male humpback salmon . . . J
Female humpback salmon .1
Male blueback salmon J
Female brook trout 1
Male landlocked salmon . . . J
Hybrid trout:
American brook trout ]
American saibling or sunapee trout . J "
jOncorhynchus kisutch (Walbaum).
' \Oncorhynchus gorbuscha (Walbaum).
[Oncorhynchus kisutch (Walbaum).
'\Oncorhynchus tschawytscha (Walbaum).
jOncorhynchus nerka (Walbaum).
\Oncorhynchus gorbuscha (Walbaum).
JOncorhynchus gorbuscha (Walbaum).
[Oncorhynchus nerka (Walbaum).
fSalvelinus fontinalis.
\Salmo sebago.
fSalvelinus fontinalis.
' [Salvelinus aureolus (Bean).
CARCINOMA OF THE THYROID IN SALMONOID FISHES. 415
Besides the American brook trout and the rainbow trout introduced into Europe,
the following European species, at least, have been observed as the subject of thyroid
carcinoma in Europe :
Atlantic salmon Salmo salar Linnaeus.
Forelle; Bachforelle; brown trout, yellow trout, brook trout,
river trout, etc Salmo fario Linnaeus.
Loch Leven trout Salmo levensis Walker.
Seeforelle or lake trout Salmo lacustris Linnanis.
Ombre chevalier, European charr or saibling Salvelinus salvelinus (Linnaeus). [Salve-
linus alpinus (Linnaeus) of most authors.]
GEOLOGICAL FORMATION AT FISH HATCHERIES.
That the distribution of goiter possesses a definite relation to the geological for-
mation has been repeatedly advanced and denied. McClellan in 1837 pointed out the
predisposing quality of the mountainous limestone and the nagelfluhe. The principal
exponent of this theory in Europe has been H. Bircher (1883). According to this author
the greatest concentration of goiter is found in the Molasse highland. The Tertiary
formation also predisposes to goiter, whereas the Jurassic formation and the primary
formation of the Alps are free from the disease. Kocher (1889), who with the assistance
of 25 of his scholars examined 76,606 school children between the ages of 7 and 15
years, was not able to justify these conclusions of Bircher, as he found that the Jurassic
formation was in no way free from goiter, neither was the fresh-water Molasse. Recently
Hesse (1911) in a study of the distribution of goiter in the Kingdom of Saxony, was
able only in part to confirm the theory of Bircher, as he found next to the highest per-
centage of the disease in the Eibenstock granite and the highest in the eruptive Mus-
covite gneiss, both of which are formations that according to Bircher should be free
from the disease. Schittenhelm & Weichardt, in the study of goiter in Bavaria (1912),
found that one of the most extensive distributions of goiter in that country was in
the Bavarian forest, which lies upon the primary granite formation. These authors
conclude that the geological formation is not a primary determining factor in the endemic
distribution of goiter, but that the infection of the water supply is. The distribution
of goiter in the mountainous southern portion of Bavaria, as well as in Switzerland,
they consider to be due to certain conditions depending upon the mountains themselves
and not their geological formation as such.
McCarrison in his analysis of conditions in the goitrous regions of Chitral and Gilgit
in Northern India finds that the water supply of the Chitral district comes from meta-
morphic rocks consisting mainly of gneiss and slate and to a lesser extent of limestone.
There are, however, certain large outcrops of limestone, and it is from these that the
most goitrous villages derive their water supplies. Likewise the highly goitrous villages
of Gilgit are supplied by water from a valley which contains a considerable outcrop of
limestone. These results are likewise at variance with the theory of Bircher concerning
the influence of geological formation.
Dieterle (1913) after a personal examination of a series of goitrous localities in
Switzerland comes to the conclusion that neither the geologic formation upon which
41 6 BULLETIN OF THE BUREAU OF FISHERIES.
goitrous regions are located or the geologic formation from which the water supply
springs is the determining factor in the incidence of goiter. He has found regions
located upon and supplied with water from pure Jura formation, with from 12 to 40
per cent of goiter, and comes to the conclusion that the boundaries of localities in
which endemic goiter occurs are purely geographic, such as certain valleys, along cer-
tain rivers, or the sides of certain mountains.
To determine whether there is any connection between the geological formation at
the various hatcheries of the Government where trout are bred and the endemic conditions
existing in most of them, we have obtained from the United States Geological Survey a
statement concerning the formation at most of the centers of fish culture throughout
the country. All the data are included here, whether the station concerned is engaged
with trout culture or not. In some cases only general information is available.
No correlation between geological formation and the occurrence of thyroid disease
is at present even suggested from the data at hand, which is here shown for purposes of
record in view of its possible future value. Most of the water supplying stations subject
to thyroid disease arises among the geological formations of primary order. Only one is
secondary (Triassic) and only a few tertiary and quaternary.
ALASKA.
Yes Bay. — Crystalline schists, probably Carboniferous.
ARKANSAS.
Mammoth Springs. — Probably in Proctor or Potosi limestone. Cambrian system.
CALIFORNIA.
Baird. — Baird formation. Carboniferous system. This underlies a bluff of the Carboniferous
McCloud limestone.
Battle Creek. — Tuscan tuff with some lava beds. Tertiary.
Mill Creek. — On border of alluvium of Sacramento Valley, and of Tuscan tuff and lava. Tertiary age.
COLORADO.
Leadville. — Crystalline rock; pre-Cambrian age.
GEORGIA.
Bullochville. — Formation not known. Probably granite and gneiss. Archean gneiss.
ILLINOIS.
Quincy. — Burlington and Keokuk limestones; Carboniferous age.
Meredosia. — Glacial sand and clay. One hundred feet more or less below the surface is Carbonif-
erous limestone. Same as at Quincy.
IOWA.
Manchester. — Devonian limestone with chert nodules.
Fairport. — At contact of Carboniferous shales on Devonian limestone.
CARCINOMA OF THE THYROID IN SALMONOID FISHES. 417
MAINE.
Boothbay Harbor. — Schists and gneisses with dikes of granite. Age unknown.
Craig Brook (East Orland). — Granite. Silurian or Devonian age.
Grand Lake. — Mica schist. Age unknown. Cut by granite of Silurian or Devonian age.
Green Lake. — Granite. Silurian or Devonian age.
Lake Auburn. — Mica schists. Age unknown. Cut by granite of probable Ordovician age.
Lake Sebago. — Granite and granite gneiss. Probably Silurian or Devonian age.
Portland. — Largely quartzose schist. Age unknown.
York. — Volcanic tuff and lava flows cut by some granite. Age unknown.
MARYLAND.
Havre de Grace. — Potomac formation. Carboniferous age.
Bryan's Point. — Talbot formation. Quaternary system.
MASSACHUSETTS.
Woods Hole. — Pleistocene glacial gravels.
Gloucester. — Probably Rockport granite. Carboniferous age.
East Freetown. — Granite. Probably Paleozoic age.
Hartsville. — Stockbridge limestone next to Cheshire quartzite. Cambrian age.
Plymouth. — Pleistocene glacial gravels and sands.
MICHIGAN.
Northville. — Cold Water shale. Carboniferous age.
Alpena. — Antrim shale. Devonian age. Has a little gas.
Charlevoix. — Antrim shale. Devonian age.
Detroit. — Antrim shale and Traverse limestone. Devonian age.
Sault Ste Marie. — Lake Superior sandstone. Cambrian age.
MINNESOTA.
Lester Park, Duluth. — Lavas of Keeweenawan series. Algonquin age.
Homer. — Immediately underlain by St. Croix sandstone, bluffs to south are St. Peter sandstone,
Shakopee limestone, Jordan sandstone, and St. Lawrence limestone. Copious spring waters come from
these sandstone formations. The St. Lawrence is of Cambrian age ; the other of Ordovician age.
MISSISSIPPI.
Tupelo. — Pleistocene sands resting upon sandy portion of Selma chalk. Cretaceous age.
MISSOURI.
Neosho. — Boone limestone. Carboniferous age.
MONTANA.
Bozeman. — Neocene lake beds. Tertiary age.
NEW HAMPSHIRE.
Nashua. — Sand beds of glacial lake. Quaternary age.
Lake Sunapee. — (East side) Granite; age unknown. Heavy cover of glacial gravel; quaternary
age. (West side.) Formations unknown.
41 8 BULLETIN OF THE BUREAU OP FISHERIES.
NEW YORK.
Bath. — Chemung formation. Devonian age.
Buffalo. — Salina formation, Silurian age, and Onondaga limestone and Hamilton shale, Devonian
age.
Caledonia. — Onondaga limestone and Oriskany sandstone, Devonian age; Salina shale, Silurian age.
Cape Vincent. — Trenton limestone. Ordovician age.
Chautauqua Lake. — Chemung formation. Devonian age.
Cold Spring Harbor. — Glacial gravel and sand. Quaternary age.
Constantia. — Medina sandstone. Silurian age.
Margaretville. — Catskill formation. Devonian age.
Old Forge. — Mica gneiss. Archean age.
Saranac Lake. — Granite, gabbro, gneiss, and schist. Archean age.
NORTH CAROLINA.
Edenton. — Sand and clay. Quaternary age.
OHIO.
Put-in Bay. — Lower Helderberg limestone. Devonian age.
OREGON.
Clackamas. — Volcanic breccia; probably Tertiary age.
Cazadero. — Volcanic breccia; probably Tertiary age.
Willamette River. — Flood plain sand and clay, Quaternary age; Sandstone, Eocene age.
Rogue River. — Formation unknown.
PENNSYLVANIA.
Bellefonte. — Trenton limestone. Ordovician age.
Freeland. — Coal measure sandstone and shale. Carboniferous age.
Weissport. — Hamilton shale. Devonian age.
Spruce Creek. — Trenton limestone. Ordovician age.
SOUTH DAKOTA.
Spearfish. — Spearfish formation. Triassic age.
TENNESSEE.
Erwin. — Honaker limestone. Cambrian age.
TEXAS.
San Marcos. — Del Rio formation. Cretaceous age.
UTAH.
Provo Valley. — Mesozoic rocks; mainly shales of Mesozoic age.
VERMONT.
Groton. — West part of town in granite. Age unknown. East part in mica slate; probably Ordovic-
ian age.
Sharon. — Mica schist; probably Ordovician age.
St. Johnsbury. — Mica schist; probable Ordovician age, with much glacial gravel of Quaternary age.
Swanton. — Trenton limestone. Ordovician age.
VIRGINIA.
Wytheville. — Shaly limestone. Cambrian age.
CARCINOMA OF THE THYROID IN SALMONOID FISHES. 419
WASHINGTON.
Baker Lake. — Limestones and schists to the south and volcanic rocks to the north and west. Age
unknown.
Birdsview. — Schists partly ferruginous. Age unknown.
Little White Salmon River. — Basalt. Late Tertiary age.
Big White Salmon. — Basalt. Late Tertiary age.
WEST VIRGINIA.
White Sulphur Springs. — Romney shale. Devonian ».ge.
WISCONSIN.
Bayfield. — Lake Superior sandstone, Cambrian age, deeply buried under glacial lake clay. Quater
nary age.
Madison. — Madison sandstone, Cambrian age, under heavy cover of glacial gravel.
CHEMISTRY OF THE WATER SUPPLIES.
There are no very definite chemical standards by which the fish-cultural value of a
water may be predetermined without the test of experience with fishes. The ordinary
sanitary analysis is of almost no value, the showing with respect to dissolved air gases,
which are of primary importance in fish culture, being usually omitted. As for a mineral
analysis, it is difficult to interpret it in fish-cultural terms since fishes thrive in waters
of such varied chemical content that conclusions can not be drawn from a statement of
the inorganic materials dissolved, unless they show the water to be so heavily mineral-
ized that it is no longer fresh, or unless it contains the metals known to be highly poison-
ous to fishes. Even in the latter case special determinations must be made and large
quantities of water used, since some metals, for instance, mercury and copper, are fatal
to salmonoids in dilutions far beyond detection in ordinary routine mineral analysis.
In order to lay a foundation for the possible establishment of fish-cultural standards
in water analysis, by long fish-cultural experience with waters whose chemical consti-
tution was determined, the Bureau of Fisheries has had analyses made of many waters
used to supply its various stations for the propagation of fish throughout the country.
These analyses have been made by the Bureau of Chemistry, Department of Agriculture.
Since not all these stations engaged in trout propagation whose water supplies have been
examined chemically have been thoroughly investigated to determine their status with
respect to thyroid disease, it is not possible to divide them into those which are subject
to and those which are free from the disease, if, indeed, there are any belonging unequivo-
cally to the latter class. We have therefore shown only the results (table u) for waters
supplying such stations as are known to have the trout thyroid disease endemic, save
the last two (no. 11737 and 11738), which supply the State hatchery at Cold Spring
Harbor, N. Y., and one of which appears to be at present free from the disease. By a
scrutiny of the mineral content of this water at the latter station, nothing distinctive
is to be found. It is low in total solids and therefore very lightly mineralized; the
chlorids, sulphates, silicates, and bicarbonates of the common earth metals make up the
bulk of the residue. These statements apply equally to many of the waters in which
420 BULLETIN OF THE BUREAU OF FISHERIES.
the disease is developed. It is in our opinion highly improbable that any of the factors
in causation of the disease are to be found among the variations of the concentration
in which the common earth salts and other matter are found in these waters.
None of the analyses shown in table n disclose any trace of iodine or bromine, but
only ordinary volumes, as a single liter, were devoted to the reactions for these elements.
In order to test further the presence of these elements in the water of the Craig Brook
station, where a large part of our data has been obtained, we have had two samples of
15 liters each used entirely by the Bureau of Chemistry for determining iodine and bro-
mine in two sources of water at the Craig Brook station. The Craig Pond water (no.
5867) is the chief water supply of the Craig Brook station. It is slightly augmented,
before reaching the fish ponds, by small volumes of spring water not subjected to anal-
ysis. The farm-house spring, whose complete content is not shown, is a minor supply
arising on the station grounds, and is probably typical of the springs of the immediate
neighborhood, such as the lawn spring (no. 5868) whose content appears in table n.
The Craig Brook water itself is in this way shown to contain i part of iodine to
1,310,000,000 parts of water; and i part of bromine to 149,000,000 parts of water. The
farm-house spring showed about the same quantities of each element: of iodine, i part
to 1,250,000,000; of bromine, i part to 142,800,000. The ratio of iodine to bromine
was the same in the two sources, i to 8.7. As the delicacy of the iodine test detects
about one one-hundredth milligram of iodine, the 1 5-liter sample contained a little more
than enough for the reaction.
Since thyroid hyperplasia begins in the Craig Brook water and is reduced by iodine
in dilutions which, though much attenuated, are yet much richer in iodine than the
above, it seems certain that the extreme dilution of iodine found to occur naturally in
the water is without appreciable physiological effect. Most brook water will probably
be found to contain iodine in quantities comparable to those in Craig Brook.
Dissolved oxygen. — No lack of dissolved oxygen contributes to the thyroid disease
at the Craig Brook station. Flowing brooks almost invariably contain all the oxygen
the water will absorb from the air. The Craig Brook water was several times titrated
for oxygen and was found to be air-saturated. The water at the outlets of troughs and
cement tanks containing trout was likewise examined and the amount of oxygen removed
by the fish was determined. A cement tank containing about 40 wild trout diminished
the oxygen content by 0.13 cubic centimeter per liter. Sixty-eight yearling trout held
in a wooden trough removed 0.4 cubic centimeter of oxygen per liter, leaving an oxygen
content of 6.8 cubic centimeters per liter at a water temperature of 15° C., which is barely
short of air-saturation.
Spring waters not infrequently emerge from the earth with a considerable deficiency
of oxygen. One such was found draining into Craig Brook, holding only 2.39 cubic
centimeters per liter at 1 7.25° C., which is about 35 per cent of air-saturation. Its volume
was insignificant, and no additions of this sort to the stream perceptibly affect its
oxygenation.
Lack of oxygenation can be excluded from the consideration of causation.
CARCINOMA OP THE THYROID IN SAI^MONOID PISHES.
421
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CARCINOMA OF THE THYROID IN SAL,MONOID FISHES.
423
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BULLETIN OF THE BUREAU OF FISHERIES.
McCarrison, in his observations (1906) on endemic goiter in India, considers the
dissolved content of the waters concerned and is unable to find anything of significance
in its relation to the amount of goiter. For the villages of the Chitral Valley, all centers
of goiter, he gives the foregoing table (table in). The meager chemical data here
shown afford no clue to the explanation of the distribution of goiter in the villages.
He gives similar data for the single water supply of the several component villages
known collectively as Gilgit, which are located in a series along the water channel from
above downward, so that an increasing pollution occurs toward the lowermost village.
There is here an increase of the incidence of goiter from above downward, culminating
at the lowermost village. In the following analysis of the Gilgit water supply, the
Barmis water is an accessory supply which drains into the main channel. No case of
goiter has been found among those who use exclusively this Barmis water.
ANALYSIS of GILGIT WATERS.
Supply.
Total
solids.
Parts per
100,000.
Total
hardness.
Grams to
gallon.
Calcium.
Grams to
gallon.
Magne-
sium.
Grams to
gallon.
Iron.
Grams to
gallon.
Sul-
phates.
Grams to
gallon.
Chlo-
rides.
Grams to
gallon.
Free.
NH».
Organic
matter.
Other
metals,
lead,
copper,
zinc.
Gilgit
o3o
7. 143
6
Trace.
Trace.
Nil.
Nil.
Nil
Barmis
6 19
8-10
Trace.
Trace.
3 or over.
Nil.
Nil.
Nil
Nil
21 grams to gallon.
ft 13.3 grams to gallon.
It is thus seen that McCarrison's chemical evidence is negative in its bearing on the
origin of goiter. The analyses are far from exhaustive, but it is to be doubted whether
greater detail would be more significant. The much more complete data which we
show for waters associated with thyroid disease in fishes is as fruitless of any theory of
causation.
ENDEMIC OCCURRENCE.
CALEDONIA HATCHERY, N. Y.
Studied from the standpoint of visible tumors, we found that in certain hatcheries
the disease is endemic. It is clear that a large proportion of the hatcheries which main-
tain Salmonidae under conditions of domestication are more or less affected by thyroid
tumors. Studied from the standpoint of visible tumors, the history of the disease in a
given hatchery may be traced backward in some cases for several years, although the
number of fish observed may be small.
The oldest hatchery in the State of New York is at Caledonia. The water supply
of this hatchery comes from springs located about a mile distant from the hatchery.
The water supply is unusually ample and there are maintained at this hatchery about
30,000 adult fish. Each year at spawning time approximately 25 to 50 visible tumors
are found in handling the fish. This condition has obtained for about 25 years, being
within the memory of the present superintendent. The fish are 10,000 rainbow trout
and 20,000 brown trout. The brown trout are the offspring of the first importation of
CARCINOMA OF THE THYROID IN SALMONOID FISHES. 425
this variety into the United States from Germany in the eighties. They have been
tinually inbred and no fresh stock has been added. The rainbow trout have been in
the hatchery for 25 years and have not had fresh stock added to them. Attempts to
maintain the American brook trout in this hatchery have been so unsatisfactory as to
have been abandoned of late years. This has been partly due to the prevalence in the
waters of the hatchery of a copepod parasite (Lernseopoda) , which does not affect the
brown and rainbow trout, but is very destructive to the brook trout. A few years ago,
however, 200 brook trout from the annual hatching were raised to the yearling age for
the purpose of exhibition at the State fair. In September, when these fish were i^4
years old, they were examined, and it was found that every individual, with the exception
of possibly a dozen, presented visible tumors, and they were for this reason discarded.
It would appear from this observation that the brown and rainbow trout in this
hatchery had gradually developed into a more resistant strain than the native brook trout
when introduced and maintained under the conditions affecting the hatchery. That
this supposition is perhaps correct is shown by the fact that at the Bath hatchery the
adult brown and rainbow trout which came from Caledonia remained practically free
from the disease during the course of what may be spoken of as an epidemic outbreak
in the latter hatchery (p. 77).
CRAIG BROOK STATION: CONDITIONS AT THE BEGINNING OP THE INVESTIGATION.
With the inauguration of a joint investigation by the Gratwick Laboratory and the
Bureau of Fisheries, a report of the presence of thyroid disease in the various hatcheries
of the Government was obtained, and from among these Craig Brook, Me., was selected
for investigation. An examination at this station made by the superintendent between
April and May, 1909, disclosed in the 6,695 fish on hand 376 with well-developed tumors.
This hatchery has been under the continuous superintendence of Mr. Charles G. Atkins
for a period of some 40 years. It is well equipped and at the time of beginning our inves-
tigation was particularly suitable for the work owing to the unusual number of salmonoid
species kept there and the fact that it was well known as one of the best conducted fish
cultural stations in the country. The scientific accuracy of its management and the
unusual completeness of Mr. Atkins's records, which extended back over a period of
years and covered nearly every factor which the progress of the investigation suggested
to us as worthy of study, gave most unusual advantages for accurate analysis of the
conditions under which carcinoma of the thyroid had developed here.
An investigation on the ground was undertaken by Dr. Gaylord, covering the months
of July, August, and September. A review of the conditions found at Craig Brook during
this first summer is contained in an unpublished report transmitted to the Commissioner
of Fisheries under date of November, 1909, and was reported during the same month at
the meeting of the American Association for Cancer Research.
Our attention was immediately attracted to an arrangement of 19 ponds containing
yearling and 2 -year-old fish. A careful examination of all the fish in these ponds during
the summer revealed the interesting fact that the incidence of the diesase increased
8207°— 14 - 5
426
BULLETIN OF THE BUREAU OF FISHERIES.
from pond to pond where these ponds communicated with each other. Figure 76 shows
the arrangement of the ponds, the general distribution of the water supply, the species
of the fish, and the incidence of the disease. The following observations on this diagram
were made at the time :
Empty.
II
Brook trout 2 years old; lot
1934 A; no visible evi-
f
Empty. |
1
1
Empty. u
1
1
Hybrid salmon i year old, i
lot 1995 ; 5 per cent visi- -
ble tumors.
1
Hybrid salmon i year old,
lot 2017; no visible evi- L
dence of disease. .
3- "x^ U _ J
dence of disease.
Y* , N
\
/
12.
1
T
1
• Brook trout 2 years old ; lot
I I939A, 3 per cent visible
1 tumors.
1
1
f
Empty.
/- 3 ' x
.- 4- >
\
/
13. -/
i Ji
. 5 N
1
V
\
\
s (
*
V
t | A II Brook trout 2 years old, lot 1937;
' r — 4j 8. 7 per cent visible tumors.
|
Hybrid salmon i year old, '
lot 1994; 92 per cent vis- f1
ible tumors.
- 6 >
,
r // Brook trout 2 years old, lot 1939; 13
,' 1*). —-It per cent visible tumors.
1
i
I
/
almon i year old, lot 1986; 84
ible tumors.
1
Empty. 1-
1
- 1
_j
\
t \C. Ji Humpback s
S •"' ~~r per cent vis
A
1
\
\
N.
/
L
Empty. |
I
Z ^
1.
f
1 Scotch sea trout 2 years old, lot 1947; no visible
0 i*« evidence cf disease.
~
1
landlocked salmon, 2 years 1
old, lot 1944; no visible L
evidence of disease.
9
Scotch sea trout 2 years old, lot I947A; no vis-
tf J 8. — ible evidence of disease.
1
landlocked salmon, 2 years 1
old, lot 1950; 24 per cent r
visible tumors.
10 >>
/
f* j Q — . Empty.
FIG. 76. — Plan of south ponds at Craig Brook station.
The water supply of ponds i to 1 1 is from a natural spring on the hillside. The
water supply of ponds 2 to 10 and 12 to 19 is from Craig Brook, the water of each pond for
the most part flowing into the pond immediately below it, pond n flowing into pond 12.
As the diagram shows, pond n contained healthy fish. These up to the time of this
CARCINOMA OF THE THYROID IN SALMONOID FISHES. 427
observation had not been fed artificial food but had found a sufficient supply of natural
food in the grass-lined pond they occupied. Lot 1939 A, 230 two-year-old brook trout,
and lot 1939, 132 two-year-old brook trout, were hatched from the same lot of eggs,
divided and placed in their respective ponds during the summer of 1908. They were
comparable in every respect except their location in the ponds, the feeding for all the
lots being the same, i. e., raw liver. Lot 1939 A occupied pond 12 next to the uppermost
pond; 1939, pond 15, three ponds below. The chart shows that 1939 A showed 3 per
cent of visible tumors, being the lowest incidence of any lot affected, 1939 15 per cent.
Between these ponds lot 1937 in pond 14, also 2-year-old brook trout, gave an incidence of
8.7 per cent. Lot 1986, humpback salmon, were yearling fish and in common with the
hybrid salmon, lot 1994 of the same age, showed the highest incidence of any of the
lots, namely, 84 and 92 per cent. Lot 1950, two-year-old landlocked salmon in pond 10,
were the least favorably placed 2 -year-old fish and showed the highest incidence for this
age, 24 per cent. (Fig. 4b.)
Here we may plainly see that the incidence of the disease increases from above
downward in the ponds, both in the 2-year-old and the yearling fish. The deduction
may also be drawn from the conditions found in these ponds that the incidence of the
disease is greater in the yearling fish than in the 2-year-old, but subsequent observations
indicate that other factors, such as the species heredity and hybridization, may so
markedly affect the susceptibility that this material is not suitable for such deduction.
(See p. 82.)
Perhaps the most striking feature of this diagram is the evidence it affords of im-
munity in certain species and certain lots. The 2-year-cfld Scotch sea trout, lots 1947
and 1947 A, were found on examination to present no visible tumors and it was con-
cluded that they were immune to the disease, a fact which microscopic examination and
further observation has confirmed. The 2-year-old landlocked salmon, lot 1944, occupy-
ing pond 9, although placed below the yearling hybrid lot, 1994, in pond 6, were also
free from the disease, although the 2-year-old landlocked salmon, lot 1950, immediately
below them in pond 10, showed the highest incidence of the disease in 2 -year-old fish.
Yearling hybrid salmon, lot 2017, were also free from the disease and in accordance
with the general scheme, the smallest incidence in susceptible hybrid salmon, lot 1995
in pond 4, is found in the uppermost pond. The further histories of the hybrid lots
and the immune fish are traced in the observations of the succeeding years.
An attempt was made to trace the history of these fish from the time they were
hatched in the hatchery through the various troughs which they occupied at different
periods up to the time of their final location in these ponds. The records pertaining
to the various lots covered the origin of the eggs, the time of hatching, the mortality
at every stage of their history in the hatchery, the temperature of the water taken three
times daily, and exact data as to the feeding, when first begun, and the amounts fed.
While it was impossible to determine the exact troughs in which, or the exact time when,
the fish might have contracted the disease, yet our attention was finally fixed upon a
428 BULLETIN OF THE BUREAU OF FISHERIES.
group of wooden troughs which the records showed had been previously occupied by
the fish that were now affected in the ponds. In October, 1909, these troughs were occu-
pied by small fish hatched the preceding spring, and from one of the troughs a small
brook trout, a so-called fingerling, was found dead and proved on examination to have a
protruding visible tumor in the* thyroid region. (See fig. 73.) On microscopic examina-
tion this was found to be tubulo-alveolar solid carcinoma, infiltrating the surrounding
structures. (See fig. 64.)
These, in the main, are the facts which were impressed upon us by the undisturbed
conditions at Craig Brook. The observations of the following summers were carried
out on a more extensive basis.
CRAIG BROOK STATION: CONDITIONS DURING THREE YEARS.
The Craig Brook fish cultural station (fig. 77) of the United States Bureau of
Fisheries is located on Lake Alamoosook about i mile from East Orland, Hancock Co.,
Me. It is but a few feet above tidewater. The station was established in 1879 for
the artificial propagation of trout and salmon, though Atlantic salmon eggs were first
hatched there in 1871-2. It is well provided with troughs in hatchery buildings for
the incubation and hatching of eggs, with troughs out of doors for the rearing of young
fish, and with earthen ponds for holding older fish and adults. Craig Pond drains
into Lake Alamoosook through Craig Brook, the whole flow of which is intercepted for
fish-cultural purposes. A small quantity of spring water is also available for the station
supply.
Fish culture at Craig Brook has been chiefly concerned with brook and rainbow
trout, the Scotch sea trout, landlocked salmon, and with hybrid trout and hybrids of
some Pacific salmon. Investigations of thyroid disease among the fish were first made
in 1909, as above stated, and have been continued more or less to date, especially during
the summer months. Thyroid carcinoma was immediately found endemic at the
station, and affected every salmonoid species or hybrid except the Scotch sea trout,
which is almost immune, and the chinook salmon.
The system of outside ponds holding adult fish at Craig Brook station is shown in
figure 78 (p. 429), and has been already referred to. A more exact study of the
water supply shows that, with two "exceptions, these 19 ponds receive brook water and
in part discharge into each other from the upper to the lower. Pond i , however, re-
ceives only spring water, which is discharged into pond 1 1 and thence drains independ-
ently of all others. The rest of the ponds are each supplied in part with fresh brook
water and in part with this water after it has flowed through preceding ponds in the
series. The ponds are entirely of earth and some have small quantities of higher
plant life, besides harboring abundant growths of filamentous green algae during the
summer months. Ponds i and n are best supplied with vegetation. (Fig. 80.)
CARCINOMA OF THE THYROID IN SALMONOID FISHES,
f Spring
4?9
FIG. 78. — Plan of ponds, Craig Brook station, showing water supply.
43° BULLETIN OF THE BUREAU OF FISHERIES.
In this pond system trout and salmon and hybrid trout and salmon, of various
adult ages and sizes and of various species, were held under ordinary fish-cultural con-
ditions, varied to a slight extent for experimental purposes, during some three years.
Nearly all were examined each summer for four consecutive years. Thyroid disease
was seen among them in all degrees of severity up to large visible carcinomata, and with
greatly varying incidence from all but complete immunity to macroscopic involvement
of more than 90 per cent of the individuals of a given pond lot.
The physical conditions in these ponds were those common to intensive breeding
of trout. All the factors of crowding, artificial food, reduced water supply, and accumu-
lation of waste products, as compared with conditions under which trout live in a wild
state, were present in greater or less degree. But the reaction of the fish to these con-
ditions, as expressed by the macroscopic evidence of the thyroid disease, was by no
means uniform but varied within wide limits.
It is of interest to consider more in detail the external evidence of thyroid growth
in these fish over a term of years. The identity of a given lot of fish is preserved by a
number. Visibly affected fish are those showing any macroscopic indication of abnormal
thyroid growth from the red floor upward. Visible tumors refer to those showing
definite tumors. It will be noticed that the loss on the lots from year to year is in most
cases considerable. This of course is not to be charged entirely to thyroid disease,
either directly or indirectly. Besides intercurrent disease, many fish are lost by depre-
dations of predatory birds and animals, and it is impossible for obvious reasons to
apportion the total loss quantitatively among these separate factors.
Table IV summarizes the condition of each lot at the summer examination during
three or four years, and gives the percentage of loss. The tumor fish were permanently
removed at each examination, unless otherwise stated. The fish with red floors only
were not so removed.
In pond i were placed, in August, 1909, 119 2-year-old landlocked salmon (1950 T),
all bearing visible tumors. They were taken from lot 1950. They were fed proteid
artificially until February, 1910, and thereafter received only such food as the pond
naturally afforded. A large measure of recovery occurred (p. 87). After one year
nearly half the visible tumors had disappeared. The next year only two fish were
left and the experiment was abandoned. In August, 1909, 28 2-year-old clinically
clean brook trout were present in pond 1 1 , and the annual remnant has remained clean
ever since. The conditions in these two ponds, which are separate from the rest of the
series, were discussed on page 68. The only water supply of pond 1 1 came from pond i ,
which contained at the beginning only tumored fish, and the fish in pond 1 1 regularly
received artificial food.
Ponds 2, 12, and 19 receive only unused brook water, while nearly all the remaining
ones receive the greater part of their supply from the next pond above and the lesser
part direct from the brook. Pond 4 had in August, 1909, 146 yearling hybrid salmon,
lot 1995 (female humpback and male blueback) with 5 per cent of visible tumors, which
were left with the clean fish. The next year there were 9 per cent and the following year
none, though the total affected fish had reached 37 per cent.
CARCINOMA OF THE THYROID IN SALMONOID FISHES.
431
Pond 5 in August, 1909, contained lot 2017, consisting of 729 yearling hybrids
(female brook trout and male landlocked salmon), all clean fish. These were the
survivors of 1,553 fish °f the previous April, all of which were clean at that time. This
lot was almost immune for two years. Only 13 red floors and 2 tumors were produced
in one year. The next year all of the remaining fish were clean, and finally in 1912
there were 10 tumored fish among the 220 remaining.
In pond 6 were placed, in August, 1909, 469 yearling chinook salmon. This pond
previously contained lot 1994, badly affected hybrid salmon. During the two years
in which these chinook salmon were kept under observation no visible thyroid process
was produced. This species (Oncorhynchus tschawytscha) is a Pacific salmon, an
anadromous marine fish. In no adult marine salmon have we seen thyroid disease.
Humpback salmon yearlings in troughs of fresh water at the hatchery acquired a heavy
tumor involvement.
Ponds 7 and 8 contained in July, 1910, 147 clean yearling rainbow trout (lot 2133).
No visible tumors have been produced. After one year 3 per cent had red floors and
after two years only 2 fish of the 31 remaining had the incipient process.
Pond 9 held, in August, 1909, 97 clean 2-year-old landlocked salmon. They
remained clean during the first year. In July, 1911, there were 10 per cent of red floors,
but no visible tumors. In August, 1912, there were but 32 fish left, of which i had a
red floor and i a tumor and red floor.
Pond 10 is the lowermost of the first row of ponds and is almost entirely supplied
by previously used water. In August, 1909, the 673 clean, 2 -year-old landlocked salmon
remaining after the removal of 219 tumored fish from lot 1950 were placed in this
pond. The loss was not excessive on this lot. By July, 1911, 7.7 per cent had visible
tumors while 37 per cent were affected, the fish having reached 4 years of age. Thus
the tumor fish of this lot recovered under more natural conditions in pond i , while the
remainder continued to develop tumors under the intensive conditions of pond 10.
Pond 12 receives 30 gallons per minute of unused brook water only. In August,
1909, 7 tumored fish were removed from the 2-year-old brook trout of lot 1939 A
and the 223 clean fish were left in pond 12. In July, 1910, but 80 fish remained, of
which 5 per cent were affected, including but one tumor. In 1911, 5 per cent had
tumors and 25 per cent were affected. In 1912 the remaining 58 fish had a slight
increase in both respects.
Pond 13 contained cyprinoid fish, which do not, so far as observed, acquire thyroid
tumors or any notable thyroid changes, and are not considered in the present study.
Pond 14 contained in August, 1909, 167 clean 2-year-old brook trout remaining after
the removal of 16 tumored fish from lot 1937. During the next year the thyroid process
progressed rapidly, 15 per cent acquiring tumors and 31 per cent becoming affected.
During the next year there was a very definite regressive process, and during the last
year, the fish reaching 5 years of age, there was again a slight progression. Pond 15
had similar susceptible fish, the process continuing slowly at first and then more rapidly.
Ponds 17 and 18 contain Scotch sea trout, which are of especial interest and impor-
tance. These ponds receive almost entirely previously used brook water, and the
432 BULLETIN OP THE BUREAU OF FISHERIES.
essential fish cultural factors are among the most pronounced of all the ponds. The
immunity of this species is apparently not quite impregnable. One case of supposed
small incipient tumor was lost by accident before a proper examination of it could be
made. Several fish with definite red floors have been observed, but these are cases of
colloid goiter rather than the hyperplastic stages comparable to those of the susceptible
species.
At Craig Brook station many unpainted wooden troughs established out of doors
are used for holding and rearing young fish until they are large enough to demand
transfer to ponds. They are each about 3.1 meters long, by 32 centimeters wide and
23 centimeters deep. (Fig. 79.) They are supplied by brook water, in part from the
hatchery building with water which had flowed through the hatchery troughs, and in part
freshly from Craig Brook. The water supply of these outside troughs flows from one
trough to the other among some of the series of troughs. Troughs 93 to 104, however,
shown in table v, receive water immediately from the hatchery. Fish are not usually
held in these wooden troughs beyond the first year, but in those of table v they have
been continued beyond the third year for experimental results with thyroid disease in
these surroundings. The fish were fed the regular artificial food, chiefly liver, and were
in general subjected to the usual artificial conditions, the space available and the water
supply being less than the earth ponds of table iv would have afforded. This series of
troughs was chosen because they were the containers of the young fish which later
showed the most visible tumors, and from one of them (no. 92) was obtained the 5-months-
old brook trout with a tumor of considerable size, the youngest fish yet found with a
visible thyroid tumor. Entirely uniform conditions obtained in these troughs. They
were of the same size and shape, supplied by the same water, subject to the same regime,
and afford the opportunity for comparable experiments.
It is seen that during these three years the brook trout, landlocked salmon, and
various hybrids show progressively increasing thyroid growth from year to year. Fish
with visibly affected thyroids not reaching to tumor formation are much more numerous
from the beginning than those with visible tumors. The latter often appear among
the yearlings, but the chief incidence is among 2 and 3 year olds. The Scotch sea trout
are exceptional and show a pronounced resistance here as in the earth ponds. No
visible tumors appear during the three years. Out of some 300 fish the second year, 2
only show the incipient hyperemia of the floor of the mouth, and in the third year i
more. These trout were plainly exposed to exactly the same conditions "'which result
in large percentages of tumor involvement in other species. Their resistance amounts
to practical immunity.
In neither the earth ponds nor the wooden troughs are the observations sufficient
to establish anything but the general conditions of fish culture or domestication, under
which thyroid disease progresses. None of the specific factors of which domestication
consists have been or can be isolated in this way. It is plain, nevertheless, that earth
ponds are unnecessary to the disease. The wooden troughs are easily kept clean and
do not become fouled for long by the accumulation of the products of the fish and
CARCINOMA OP THE THYROID IN SAI^MONOID FISHES. 433
the unused food. The material of the trough, though water-soaked, affords no perma-
nent lodgment for gross particles of organic matter.
Since thyroid carcinoma in fishes is rare in nature and common in domestication it
would seem that some or all of the conditions of domestication — artificial propagation
of fish — either by their own direct action cause the disease, predispose to it, or carry
its cause to the fishes. That domestication itself, viewed as a single complex whole,
is per se the cause of thyroid disease, is a priori highly improbable, and is negatived
by the occurrence of thyroid tumors in wild fish. This occurrence, though sporadic
and rare, is now established beyond dispute and is a fact of great significance. Domesti-
cation predisposes to the disease and carries the causative agent to the fishes, and some
one or very few of the constituent factors or conditions of domestication is probably
of chief importance in this action. From a study of the conditions at such a station as
Craig Brook, while the disease is spontaneous and endemic under the routine of fish
culture, it is difficult to fix accurately upon any one of these conditions to the exclusion
of others as the prime essential. Feeding is probably more important than any other
one factor. The removal of feeding or change to natural food tends toward the recovery
of affected fishes, and prevents or delays the initial process. The inevitable reduction
in the available unit of water supply per fish and the crowding of fish together in small
areas are no doubt factors of next importance. We do not believe that the soluble
products of metabolism and of the disintegration of organic matter left from feeding
or otherwise play any important part in the origin or progress of this disease, unless
as creating more favorable conditions for the development of a causative agent. An
unfavorable general hygiene of the fish predisposes to the disease, domestication itself
as usually practiced involving a more or less unfavorable hygiene, and in this way
these soluble products may enter somewhat into the problem of causation.
434
BULLETIN OF THE BUREAU OP FISHERIES.
TABLE IV. — INCIDENCE ov THYROID CARCINOMA IN DIRT PONDS, CRAIG BROOK, 1909-1912.
[Where there are two entries for August, 1909. under total number of fish, the number before and after removal of tumored
fish is indicated.]
Pond
No.
Lot No.
Date.
Age.
i
Species.
Total
number
fish.
Visibly
affected.
Visible
tumors.
Loss.
Years.
Per cent.
Per cent.
Per cent.
do
39
56. o
.do
a
50. o
. o
8s- 7
( M2
(?)
5-5
"
do
I 138
.0
.0
do
Hybrids &
July, 1910
...do
543
3-o
do
.do
6
Aug., 1909
Chinook salmon
469
July, 1910
...do...
• O
July, 1911
do
53
.0
• o
76. 9
July, 1910
Rainbow trout
July, 1911
.. do
8
July, 1910
....do
70
8
July, 1911
....do
46
.0
7-8
Aug., 1912
do
6.4
July, 1910
...do
73
July, 1911
4
do
66
.0
Aug., 1912
5
do
32
6.2
3. i
10
Aug., 1909
do
( 2"
(?)
24-5
July, 1910
do...
\ 673
6<>o
.0
.0
July, 1911
.do
II
Aug. 1909
Brook trout
S8?
July, 1910
...do...
65
(?)
July, 1911
...do....
28
Aug., 1912
5
do
8
13
Aug., 1909
do . .
/ 230
(?)
3-0
July, 1910
.do
\ 223
80
.0
.0
July, 1911
...do
80
Aug., 1912
do
58
do
/ 183
(?)
8-7
July, 1910
...do...
I 167
76
. o
.0
July, 1911
do
c 6
6 6
Aug., 1912
do
.0
15
Aug., 1909
....do
/ 133
(?)
iS-o
July, 1910
...do...
1 "3
. o
6 7
.0
July, 1911
...do...
8 8
Aug., 1912
5
do
17
Aug., 1909
Scotch sea trout
5
July, 1910
....do
1
'
July, 1911
...do...
18
16 T
'
Aug., 1912
5
...do...
'
*
18
i94?A
Aug.. 1909
...do...
July, 1910
3
do
1 88
July, 1911
4
do
* .g
Aug., 19:2
5
do
6.0
° Female, humpback; male, blueback.
fr Female, brook trout; male, landlocked salmon.
CARCINOMA OF THE THYROID IN SALMONOID FISHES. 435
TABLE V. — INCIDENCE OF THYROID CARCINOMA IN WOODEN TROUGHS, CRAIG BROOK, 1910-1912.
Trough
No.
Lot No.
Date.
Age.
Species
Total
fish.
Visibly
affected.
Visible
tumors.
Loss.
\~tar
Brook trout
Number.
59
Per cent.
28.0
Per cent.
Per cent.
.. ..do
35
6s- 7
40. 7
Hybrid trout, 5 brook, (f saibling
86
. . do
77
IO.O
....do
60
48. 3
22. O
2081
l,anHlorkeH salmo™ , ,
.6
... do
5. 2
.6
do
26.6
. 7
21.9
06
Brook trout
85
ii. 8
do
66
25. 7
.do
62
6.6
•oft
Hybrid trout saibling brook
5.8
do
62. i
...do
28
28. 2
2038
Aug., 191
do
87
8.0
7.0
July, 191
do
J3
17. 4
13- o
73.5
Aug., 191
do
II
54. 5
1 8.0
52. t
898
July, 191
...do
.6
.0
63.0
Aug., 191
do
303
I. O
.0
8.7
2O5jB
Brook trout
4.6
)
July, 191
do
60
61.6
38.3
\ («)
Aug., 191
do
47
91. 5
j
lOJ
Aug., 191
do
205
. 5
. 5
July, 191
... do
53. I
Aug., 191
do
76
43. 4
6.6
2O. O
Aug., 191
...do...
69
16. o
4.0
July, 191
....do...
64
59. 3
9.3
7. I
Aug., 191
do
53
70.0
17.0
17. I
o Many fish used in experiments.
LAKE AUBURN HATCHERY, MAINE.
This is a State hatchery in Androscoggin County. In August, 1910, an examination
of fish for visible tumors was made and the general conditions inspected. Pond i was
a dirt pond fed by two springs of water very cold at its origin, and standing at 11° C.
in the pondon August 20. The spring water has a very low content of dissolved matter
and is said to have about the same analysis as the well-known Poland Springs of Maine.
The pond held nearly 400 brook trout of 3^ years of age, which had occupied the pond
since the yearling stage. They had been fed raw beef liver until a year old and raw
beef heart ever since. The fish were raised from eggs from the local station and from
domesticated eggs obtained from Michigan. They were apparently in fine condition,
were feeding well, and had suffered but little loss. One hundred and thirty-one of these
trout were examined, of which 20.5 per cent showed visibly diseased thyroids and 5.3
per cent of the 131 bore visible tumors.
Pond 2 was a similar dirt pond, fed from six independent springs and sometimes
by the overflow of pond i. Its water was warmer, being 15.5° C. It held 4-year-old
brook and brown trout and adult landlocked salmon. A seine haul of fish were exam-
ined. Of 66 brook trout, 21.5 per cent had visible tumors and 19.5 per cent red floors;
of 15 salmon, i had a red floor and 4 had visible tumors; of 36 brown trout all were
entirely clean, without external sign of thyroid proliferation. The food was beef heart.
There was no marked mortality rate, but there was a heavy loss on spawn taken from
the fish of this pond.
436 BULLETIN OP THE BUREAU OF FISHERIES.
Of a large number of yearling landlocked salmon held in a small pond, 102 were
examined. Seven fish were affected, three having red floors and four visible tumors.
There is nothing extraordinary about the conditions at Lake Auburn hatchery, which
shows rather a typical case of the endemic occurrence of the disease. Here are spring
water, dirt ponds, the common proteid foods, liver and heart, and adult fish in excellent
condition from the ordinary fish cultural standpoint, and with no unusual mortality
rate, but a considerable morbidity in visible thyroid enlargement, with immunity of
the brown trout.
At two other State hatcheries similar or greater morbidity has been determined
from actual examination, and reports from superintendents of both Federal and State
hatcheries indicate the general extent to which these conditions obtain, with some few
exceptions, throughout the territory of trout culture in the United States.
PRIVATE HATCHERY IN THE STATE OF WASHINGTON.
At North Yakima, Wash., an interesting and instructive example is afforded of
endemic occurrence among young trout at a newly established private hatchery where
30,000 brook trout were held in earth trenches supplied by spring water. The food for
the first six months was liver, after that horse meat. The hatchery was started in
March. In the following December, before the trout were a year old, thyroid tumors
were observed among them, about i per cent being affected. The several specimens
we have examined show tumors which, relative to the size of the fish, are among the
largest we have seen. One of these was 13 millimeters in diameter in a trout 8.5 centi-
meters in standard length. Microscopically the structure shows solid carcinoma,
among the most malignant of our examples.
Rainbow trout of the same age and living under exactly the same conditions at
this hatchery are not affected with thyroid tumors. The region in this part of the
State is said to show a high percentage of goiter among female children and among calves
and other domestic animals. Statistical studies, however, have not been made.
This instance shows an unusual acceleration of the thyroid process. Malignant
carcinoma of large size developed in trout under i year of age and during the first year
of a fish hatchery. Obviously domestication of long duration, either in the individual
fish or in the local station where the fish are held, is unnecessary. Something local at
this particular fish hatchery seems to be concerned in the unusual result. Certainly
the general conditions of trout culture as expressed at the numerous stations where
trout are bred do not result in the rapid course of disease here shown. Is there merely
a local intensification at this hatchery of the essential cause of the disease?
EPIDEMIC OCCURRENCE.
"The hatchery at Bath, N. Y., referred to in the introduction as having first
attracted our attention to this condition, was, up to 1907, free from visible tumors.
From the accompanying diagram (fig. 81) it will be seen that the water supply of this
hatchery comes from a large pond (A) fed by several springs on land adjoining the hatch-
CARCINOMA OF THE THYROID IN SALMONOID PISHES.
437
438 BULLETIN OF THE BUREAU OP FISHERIES.
ery, and many larger and smaller springs in the pond itself, and that this supplies the
greater portion of the water to the hatchery. This water is supplemented by a large
spring B, forming one system of water supply, while the water from springs C and F
forms the other, the two systems uniting in race 12. The water coming from the large
pond is aerated in fountains K and L. Springs D and E tap a vein running in a northerly
direction at a depth of about 15 to 25 feet. The water from these two springs is now
used exclusively in the hatchery building for hatching this season's spawn. The large
pond A maintained in 1907 an unknown number of fish living under wild conditions,
being fish which from time to time were placed in the pond, where they had then shifted
for themselves. The pond is grass-grown about the banks, has a plentiful growth
upon its bottom, and presents practically an ideal approach to wild conditions. (Fig. 82.)
In 1906 a brown trout approximately 2 years old was found dead at the outlet
of the big pond, and on examination presented two well-developed tumors at the junc-
tion of the gills. This was the first evidence of the disease which the superintendent
had noted. In September, 1907, pond A was emptied, a large portion of the fish in it
escaping into the brook. After cleaning the bottom, removing the grass, etc., the
pond was stocked with about 6,000 brook trout fry hatched in the hatchery, and sys-
tematic feeding with liver was, for the first time, practiced in this pond. From August
to October, 1908, a few of the yearling fish in the large pond were found dead with visi-
ble tumors. In October the fish in the lower races supplied from the big pond also began
to die in sufficient numbers to attract attention, and a large proportion of these were
found also to have visible tumors. During the summer of 1908 not less than 3,000 fish,
exclusively brook trout, died in this hatchery with visible tumors. During this period
of the outbreak some 1 75 adult rainbows held in one of the lowermost ponds, to which
ran the water from the spring running through the races seriously affected, remained
free from the disease, with the exception of i fish found late in the season. Some
4,000 yearling brown trout from Caledonia remained free from evidence of visible
tumors, as did also some 220 four-year-old brown trout from the same source.
During the summer of 1909 epidemic conditions obtained in this hatchery in more
aggravated form than in any previous year. The stock fish as well as the fry were fed
almost exclusively on beef livers, obtained twice a week from the Buffalo abattoirs. A
large proportion of this liver fell to the bottom of the large pond and there decayed.
The food not eaten up in the races was brushed out frequently enough to prevent con-
tamination. About 200 pounds of beef livers were fed weekly in the hatchery. A
number of times livers were found with large single or multiple abscesses.
The stock fish in the hatchery in 1 909 consisted of the following, some lots of which
may be recognized as having figured in the occurrences in the hatchery of 1908 — 125 to
150 rainbows held in concrete race 13; 3,000 two-year-old brown trout from Caledonia
in races 22 and 23; 76 older brown trout; and 700 to 750 brook trout of varying size
and age. During the course of the summer the rainbow trout retained their relative
immunity to the disease, only 7 developing visible tumors during the summer, notwith-
standing the position of pond 13, receiving water from both water supplies, all of it
running through troughs and concrete tanks above, in which the disease was very active.
CARCINOMA OF THE THYROID IN SALMONOID FISHES. 439
The remainder of some 200 five-year-old brown trout referred to in the summer of 1908
as free from tumors were again examined closely and found to be in a healthy condi-
tion, showing no visible tumors.
A distinct change, however, was found in the 4,000 brown trout from Caledonia,
which in 1 908 showed no evidences of visible tumors. This lot is described in 1 909 as
consisting of about 3,000 fish, now 2 years old, from 6 to 8 inches in length. These occu-
pied cement races 22 and 23. Owing to insufficient help, it was not possible to examine
all of these brown trout. However, it was possible to determine that the disease in this
lot was now well established. Forty-eight died or were picked out from the lot and found
diseased. This does not represent the total number of brown trout affected. Between
June and the end of September, among the fish which died from this lot, 43 are recorded
as having been examined and all showed visible thyroid tumors.
The brook trout of the hatchery were yearling fish, between 700 and 750 in number,
kept in races 10 and n. A number of them were also kept in race 14 and in the large
pond. In race 16, wooden, were 100 brook trout from Cold Spring Harbor hatchery.
To these were added 56 wild brook trout from the Old Forge hatchery later in the sum-
mer. By the middle of June the epidemic among the brook trout was at its height.
These fish were examined a number of times and some of the affected ones were put
into the large pond and others into the small pond 15. On June 24 the fish in race 10
were examined and 72 affected fish put into the large pond. About i fish in every 3
was found with visible tumors. Race n contained 142 yearling brook trout. Thirty
affected fish were found in race n and placed in pond 15.
The remainder, 112 supposedly healthy fish, were removed to wooden race 18.
This race is supplied with the water of springs C and F, and the Cold Spring Harbor
trout kept in this water having remained free from the disease it was hoped that by
changing the fish from race 1 1 , which did not yet show evidences of visible tumors, they
might be saved. On examining these fish in race 18 in September, 107 of the 112 were
found to have visible tumors.
During the summer a large number of the brook trout in the large pond died. One
hundred and five of these were found to have visible tumors. Early in the spring the
large pond which in September, 1907, had been stocked with some 6,000 brook trout
fry hatched during that season and in which during the summer of 1908 a few dead
yearling fish were found with visible tumors, was again cleaned, the fish being tempo-
rarily transferred during this time. Some 200 of these brook trout, now 2 years old,
were estimated to have escaped with the overflow into the brook. This stream was
protected by a screen at the lower end of the hatchery and such fish as escaped
remained in the brook during the summer, here receiving no artificial feeding during
this time and enjoying conditions of freedom so far as ample space and lack of crowding
were concerned. That a large proportion of these fish were affected with visible tumors
was shown by the fact that during the course of the summer 105 died of the lot trans-
ferred to the big pond, all showing visible tumors, and to determine to what degree they
might have recovered under the new conditions an examination was made on Sept em-
44-O BULLETIN OF THE BUREAU OF FISHERIES.
ber ii. The stream was therefore seined and 48 fish were caught and examined. Of
these 3 1 were found to have visible tumors, many of large size.
Pond 15 had been the receptacle for affected fish taken from the different troughs,
tanks, and ponds. There were approximately 450 fish in this pond; 164 of these are
recorded as dying during the course of the summer. At the end of September the
remainder, all of which still had visible tumors, were killed; the record states 276 in all.
The conditions for observation at the Bath hatchery during the summer of 1909 were
unfavorable owing to lack of records as to the origin of many lots of fish, to inadequate
help, preventing frequent examination of the various lots, and to frequent changes of the
various lots from pond to pond, due to the exigencies of fish culture. The most important
observations made were the marked degree to which the water of the big pond and the
tanks it supplied were involved in the epidemic; the striking evidences of immunity in
the adult rainbow and brown trout from the Caledonia hatchery; the fact that the
yearling brook trout exposed to the disease in pond 1 1 continued to develop it rapidly
although transferred to trough 18, in which nevertheless the Cold Spring Harbor yearling
brook trout in trough 16, which was supplied by the same source, springs C and F,
remained free from the disease during tne summer; and the lack of evidence of spon-
taneous recovery in the 2-year-old brook trout living under conditions of partial freedom
without artificial feeding during the summer in the brook; the high incidence of the
disease in the large pond, A, where the flow of water and proportionately great area
of the pond produced conditions much more favorable from this standpoint than are
usual under conditions of domestication; and the rapidity of involvement of the fish
by the disease and the great number affected.
As the main activities of this research were, in 1909, transferred to the Craig Brook
station in Maine, no further observations were made at the Bath hatchery during 1910
and 1911, but in the middle of October, 1912, for the purpose of determining what the
condition of this hatchery might then be, an inspection, covering one day, was made.
No essential changes have been made in the water supply or other arrangements of
the hatchery other than those already described. The hatchery now carries a stock
of about 3,000 brook trout hatched in the spring of 1911. With the idea that fish
hatched from the eggs of wild fish might prove more resistant to the unfavorable con-
ditions in this hatchery, eggs were obtained from the Ontario Fish and Game Commis-
sion in Canada. Approximately 1,500 fish were hatched from these eggs and main-
tained in a separate trough. The remaining 1,500 fish were hatched from eggs obtained
from a private hatchery in Massachusetts, and were also kept in a separate pond. Both
these lots of fish showed well-developed examples of the disease ranging from the first
evidence of red floor to protruding tumors of 7 to 10 millimeters. Of the 1,500 fish
hatched from the wild-fish eggs, some 200 were examined, 9 of which were visibly affected,
and 200 examined from the lot of 1,500 hatched from the eggs from the Massachusetts
hatchery showed 12 diseased fish. From this inspection it is evident that the disease
is still endemic at the Bath hatchery.
CARCINOMA OF THE THYROID IN SALMONOID FISHES. 441
HYBRIDIZATION.
Hybrids of the brook trout with the American saibling (Sunapee trout) and with
the landlocked salmon do not differ materially from the pure species in reaction to
thyroid disease. Lot 2017, for instance (female brook and male landlocked salmon),
as yearlings showed no visible process, and experienced very little involvement during
four years. Lots 2036, 2037, and 2038 (brook plus saibling) were little affected as
yearlings, but considerably at three years. The appearance and character of the growth
is substantially the same as in the brook trout. These crosses, within the genus Salve-
linns and the closely related Salvelinus plus Salmo, are more or less successful, and
the fish resulting are hardy, and grow to maturity and reproduce.
The hybrids of the Pacific salmon, though all contained in the same genus (Onco-
rhynchus) , are greatly inferior in vigor to their constituent species, and probably could
not maintain themselves. They do not do well under fish-cultural conditions, are not
hardy, and easily succumb to unfavorable conditions. Hybrids of the silver and hump-
back salmon are subject from the embryo to deformity of the spinal column in the
region of the caudal peduncle. They are readily susceptible to thyroid disease. One
of these hybrid lots showed as yearlings the highest incidence of visible tumors yet
observed in any large homogeneous brood of fish (p. 67). One lot, however (silver
plus humpback, igSSA), consisted at the first examination of but 17 fish, all of which
were tumored; and all the Pacific hybrids showed a high percentage of tumors. The
general gross appearance of these growths is markedly different from that of the trout
tumors. The hybrid tumors have a marked symmetry, most apparent on the floor of
the mouth. Here the growth as it vegetates into the mouth usually occupies the median
bridge, and spreads equally over the arches so that the right and left halves of the
tumor are alike, and a distinct and sometimes almost perfect bilateral symmetry appears.
The surface of the growth is unusually smooth. The benign impression which results
is belied by the structure, which in these growths in hybrid salmon is among the most
malignant of the thyroid tumors in fishes. Likewise the cachexia observed among
tumor fishes is most extreme in these fish. (Fig. 4a).
CLINICAL COURSE.
MORBIDITY AND MORTALITY.
There is no very definite symptom picture among the affected fishes. The disease
usually runs a slow chronic course. The earliest external evidences may doubtless
occur in very young fish only a few months old, but rarely do fish of this age show any
outward signs of disease. The beginning of the process is without clinical symptoms
until the red floor or an evident tumor appears. The earliest gross tumor we have seen
is in a brook trout about 5 months old. (Fig. 72.) Not many tumors are seen until the
fish reach the yearling stage, when the growth is usually still small and not causing much
interference. In certain hybrid salmon, however, and occasionally in brook trout, the
growths in yearling fish have already reached a relatively great size, sometimes almost
their maximum. These hybrids die rapidlv and do not grow to maturity. In brook
8207°— 14 6
442 BULLETIN OF THE BUREAU OF FISHERIES.
and other pure trout species the tumors grow progressively with the growth of the fish
to maturity. At the spawning season gravid fish are often thrown out and destroyed
on account of the presence of large thyroid tumors, and doubtless eggs from such fish
not infrequently find their way into the hatchery. As far as we know they may be fer-
tilized and hatched like the eggs of other trout.
Only the larger tumors are evident to a casual inspection of the fish. To determine
whether a fish has a thyroid tumor it is necessary to examine the thyroid region from all
sides after spreading wide the gills and opening the mouth. A considerable proportion
of the trout in fish-cultural ponds may have developed visible tumors without the knowl-
edge of the fish culturist. By such an examination 31 per cent of the 2-year-old brook
trout at one hatchery were found to have visible thyroid tumors, while 33 per cent
showed the red floor indicative of an earlier stage of thyroid disease.
Thus 64 per cent were visibly affected, although the fish culturist knew of the exist-
ence of this disease only from having occasionally seen a dead trout with a swollen gill
region.
The first obvious effect of the tumor is the mechanical interference with breathing
and eating as the tumor grows larger. By filling the mouth it obstructs the passage of
food, and by its growth downward and outward it spreads the gill arches, limits their
natural movement, and pinches off the vessels until in portions the circulation is stopped.
Large tumors often show across their surface a pale atrophied series of nonfunctional gill
filaments. Yet the fish succeeds in breathing and eating in spite of a surprising degree
of interference.
Tumored trout, like healthy normal trout, ordinarily have the blood sterile to com-
mon culture media. This is shown by negative results from numbers of attempts to
obtain cultures from the heart blood of freshly killed trout with tumors, and also from
tumor trout dead of disease. That tumor trout are more subject to terminal infection
than other trout is to be expected and is probably the case, though some meager observa-
tions made by us at a State hatchery tend rather to support the contrary view. Ter-
minal blood infection in the living as well as the dead trout has, however, been observed,
and of course the tumors are frequently infected. That tumor trout frequently die
without showing a general infection, or evidence of intercurrent disease, indicates that
the thyroid process itself is fatal in a certain proportion of cases. This intrinsic death
rate is probably low, but can not easily be separated from the rate of mortality among
tumor fish due to all causes. *
Hybridization seems greatly to increase the susceptibility of the salmonoids to the
incidence of tumors and to its effect on their bodily economy. In some of these the
anemia is readily recognizable by mere inspection, and is so extreme in some individuals
that the blood scarcely appears red. A case in point is the lot (no. 1994) of yearling
salmon (Oncorhynchus) hybrids of the female blueback with the male humpback. In
April they numbered 1,043, °f which 16.7 per cent had visible tumors. By the following
August they had suffered a loss of 57 per cent. Of the 594 remaining 92.5 per cent
had visible tumors. These showed distinct emaciation, many of them to an extreme
CARCINOMA OP THE THYROID IN SALMONOID FISHES. 443
degree, with the accompanying anemia referred to above. They were constantly suc-
cumbing to the disease, and the slightest handling, as during the manipulations incident
to transportation, greatly increased the death rate. Before the following summer all
were dead. The reaction of the disease in hybrids does not afford a typical clinical
picture and is not a criterion from which to infer its virulence or its analogies with other
disease processes. Most hybrids are not successful fish-culturally, and the salmon hybrids
referred to are especially defective and lacking in vigor.
Restricting morbidity to those showing macroscopic evidence of disease, such as
red floors or visible tumors, the morbidity rate is widely variant among the various
species and hybrids, and under the various conditions of age and surroundings. Our
observations show, for brook trout yearlings, a rate from a minimal one-half of i per
cent to 28 per cent; for 2-year-olds, 20 per cent to 65 per cent; and for older fish from 5
to 91 per cent. Considering visible tumors only, there appears one-half of i per cent
to 7 per cent for yearlings, 3 per cent to 38 per cent for 2 -year-olds, and i per cent to
34 per cent for older fish. Landlocked salmon have shown visible evidence of disease in
from 2 per cent to 7 per cent of yearlings, and 5 per cent to 37 per cent of older fish.
With rainbow trout our experience is very limited, and we have not seen more than 6
per cent of adults affected.
Hybrids of the brook trout and saibling react much like the brook trout, but hybrids
of the brook trout and landlocked salmon seem, from experience with one lot only
(no. 2017), to have a considerable degree of immunity, showing no involvement until
the second year, and at 4 years only 5 per cent were affected. The salmon hybrids of the
genus Oncorhynchus usually show extreme susceptibility.
On the other hand, the same hybrid with the sexes reversed (lot 1995, male blueback
and female humpback), was much less susceptible. It was held at first under the same
conditions, in trough 99, and consisted in April of 312 yearling fish, only 1.2 per cent
bearing tumors. In the following August there were 146 fish left, of which 5.5 per cent
had tumors. The clean fish were then transferred to pond 4. At 2 years of age there
were 77 fish left, of which 13 per cent were affected and 9 per cent had visible tumors.
At 3 years of age 27 fish were left, and of these 37 per cent showed red floors without
any visible tumors.
The direct and indirect mortality rates can not be stated numerically. The process
presumably does not kill, whether directly or indirectly, save in the later stages when
the tumor is visible, and the only available data on the loss among fish in any stage of
thyroid disease is so complicated with losses from other causes — even causes having
nothing to do with disease, that any accurate statement is impossible. The mortality
rate is to all appearances not uniform, but varies from a slow fish-culturally unimportant
loss to occasional epidemic virulence, as in the active progress of the disease and rapid
loss of fish at the State hatchery at Bath, N. Y. Ordinarily and in the common exhibi-
tion of the disease the death rate may be said to be low.
In the many studies of the distribution of goiter among human beings none is so
striking or apparently so directly comparable to the conditions found in the study of
the disease in fish hatcheries, as the observations of McCarrison, 1906, of endemic goiter
444 BULLETIN OF THE BUREAU OF FISHERIES.
in the Chitral and Gilgit Valleys of north India. McCarrison had the opportunity of
studying endemic conditions among the inhabitants of the small villages of this remote
region. His observations are of particular value because the people in these small
States of northern India are remote from commerce, communication is extremely limited,
many of the communities are shut off from communication even with their neighbors,
and the conditions which he describes represent the development of the disease under
almost fixed conditions. In the Chitral Valley he describes a series of villages lying
along the left bank of the Chitral River, each village deriving its water supply from
the narrow mountainous valleys at the openings in which the villages lie.
The water supply is in all cases derived from the melting of the snows on the hills above. It comes
from the nullah at the mouth of which the village stands, and is the only supply of that village. As a
rule the water from the melting snows runs down the nullah as a turbulent mountain stream, taking
up what matter it may on its way either in solution or suspension; in other cases it percolates into the
soil and appears lower down in the form of a spring, as in the case of Awi. In the summer months the
water is invariably gray from the presence of fine sediment. There are no real glaciers in the district
under observation ; the water is snow water rather than glacier water. There are no wells in the village ,
and, owing to the slope of the ground and the nature of the soil, water does not and can not stagnate.
The incidence of goiter in these villages varies from 10 per cent to 58 per cent and
appears to be dependent upon the local conditions of the village and its water supply.
As compared with the appearance of the disease in the villages of Chitral, McCarrison
had observed in Gilgit a remarkable increase of the incidence of goiter in a series of
villages scattered along an irrigation ditch where the incidence of the disease increases
from above downward.
Gilgit lies between the parallels of latitude 35° and 37° and meridians of longitude 74° and 75°.
It is only, however, with Gilgit proper, the capital of the district, and not with the whole of this district
that these observations deal. Gilgit is situated on an alluvial fan on the right bank of the Gilgit River,
a tributary of the Indus. This fan is roughly 10 square miles in extent and has a gentle slope from its
apex, in the nullah from which it derives its water supply, to the river. On this extensive fan eight
villages are situated; collectively these are known as Gilgit. The remarks which I have made as to
the climate and people of Chitral apply equally to Gilgit. The valley runs east and west. The height
of the fan above sea level is 5,105 feet. Appended is a rough diagrammatic sketch which shows clearly
the water supply of the different villages of the Gilgit fan.
The water comes from a single source and is conveyed to the different villages in open kuls or chan-
nels. From the diagram it will be observed that there are two main channels, an upper 11 and a lower
(i). The upper channel has no villages on its banks till it joins the lower kul, at the village of Majin-
pharri, marked (3). All these seven villages are situated on the banks of this lower kul or are supplied
by lesser channels branching from it. Each village in this way receives the drainings" of the village
or villages above it, till at the last village, Kashrote, the drinking water has been polluted by the six
villages above.
The water in these open channels not only supplies the inhabitants with drinking water, but it
irrigates their extensive crops, serves as an open sewer, is used for the cleansing of their bodies, house-
hold utensils, and wearing apparel. It can readily be imagined, therefore, that considerable organic
impurities find their way down to the lower villages; yet, being fed as these channels are by a purer
supply, little organic impurity can be detected by qualitative tests.
The water is, during the winter months, at its source clear and sparkling, but at the village of
Kashrote (see diagrammatic sketch of water supply and plate Gilgit Valley, western end) invariably
gray from the presence of fine sediment and impurities from the villages and lands irrigated by it.
During the summer months when the snows are melting it is, of course, much worse.
CARCINOMA OF THE THYROID IN SALMONOID FISHES.
445
If the sketch of the Gilgit water supply is referred to it will be observed that the Barmis spring
joins the supply already described at 3, Majinpharri. This spring does not produce goiter; it is the
supply of all the European residents and their servants; there is also a small village on its banks, among
the inhabitants of which there is no single case of the disease. It is a very pure water, springs from
5.
FIG. 83.— Diagrammatic sketch showing water supply of the villages of Gilgit fan, India. After McCarrison.
among rocks, and I have been unable to trace any case of the disease due to the drinking of its water.
This is a point of very considerable importance, showing as it does that the other water supply is the
vehicle by means of which goiter is produced in the inhabitants of Gilgit. The analysis of this water
of Barmis will be found in the table of analyses of Gilgit waters (table in).
446
BULLETIN OF THE BUREAU OF FISHERIES.
In considering the prevalence of goiter in the villages of Gilgit the villages are dealt with in order,
from that highest on the water supply to that lowest (see sketch of water supply). The figures are given
in the following table:
i
Village.
Popula-
tion.
Houses.
Infected houses.
Persons
infected
in
infected
houses.
Total
popula-
tion
goitrous.
z. Basin
Number.
93
38s
181
718
229
458
128
Number.
15
66
30
108
33
63
24
Number.
9
42
20
68
23
5»
21
Per cent.
60. o
63-6
66.6
63- 2
71-5
82.S
87.0
Per cent.
ai. a
28.3
3°-3
24. 2
3O.O
30.0
36.0
Per cent.
u.8
20.0
1 8. 8
20.0
26.9
24- S
45-6
2. Umpharis
3. TD^Tiy^l ,
4. Majuiipharri
5,6. Kyk
g. Kashrote
It is quite clear that McCarrison has observed conditions which are remarkably
comparable to the conditions found in the Craig Brook hatchery where we originally
found the increase of the disease from above downward in the ponds, with absence of
the disease in the two uppermost ponds fed with individual spring water supply
(fig. 78, p. 429) ; also to the conditions which we have described at Cold Spring Harbor.
The age incidence of visible manifestations of this disease including both red floors
and tumors affords material for a comparison of the incidence of the disease as we have
observed it in fish and that of goiter in the inhabitants of the villages of Chitral and
Gilgit Valleys, as recorded by McCarrison, as well as that of goiter in school children
as given by Schittenhelm and Weichardt. McCarrison examined 646 inhabitants of
the villages of Chitral, of which 277 were children under 15, and 369 adults. At 5
years of age male children showed 40 per cent, female 22 per cent. The incidence of
the disease rises rapidly to 15 years where the males' showed 74 per cent, females 59^
per cent. From this age it rapidly fell in both cases so that at 25 years of age males
showed 40 per cent, females 24 per cent. From 25 years on, the incidence in females
again rose, until the age of 45 when 62 per cent were affected, the males having steadily
fallen to 23 per cent at the same age period. In Gilgit the total population examined
was 1,533, °f which 705 were children under 15 years and 828 adults. The incidence
for males and females varies slightly. At 5 years of age 2 per cent of the males and
at 1 5 years of age 1 6 per cent of the males and 20 per cent of the females were affected.
In this locality the incidence steadily rose to 40 years of age when 45 percent of the
males and 36 per cent of the females were affected. McCarrison states that in Chitral
23 per cent of children under i year of age who are still being suckled suffer from this
disease in the village of Awi, and in another village, Miragram, the percentage figure
was even higher than this, reaching 61.5 per cent. The mothers had in all cases been
the subject of the disease and frequently the fathers also. What proportion of these
cases were congenital and what acquired he was unable to determine.
Schittenhelm and Weichardt state that in a typical goitrous community in Bavaria
the incidence of goiter as expressed by demonstrable enlargement of the thyroid is,
from 2 to 6 years of age, 42 per cent; 6 to 9, 72.4 per cent; 9 to 13, 89.6 per cent; and
CARCINOMA OF THE THYROID IN SALMONOID FISHES. 447
that for recruits who have reached the age for military service for the district, 9.22
per cent. From this it would appear that there is a steady increase of goiter in school
children up to the age of puberty, with a marked decrease between that age and 20.
Our tables show that for brook trout yearling fish the maximum is 28 per cent,
.or 2-year-olds 65 per cent, and for fish older than 2 years 91 per cent. It may be
stated for brook trout in captivity that a large proportion of them at least have acquired
their reproductive faculties in the second year and that their full reproductive faculties
are certainly acquired by the third season. It thus appears from our figures that fish
exhibit a very high, probably the highest, incidence in the period from 2 to 5 years,
which in the life of a fish carries it well beyond the comparable period in human beings.
We have frequently met with instances of actively growing tumors in the oldest fish
under observation and the large tumors in old fish have never presented an appearance
comparable to colloid goiter. So far as this comparison is admissible it would indicate
that the process in the fish in its age incidence is more in accord with McCarrison's
observations than the Bavarian statistics just quoted. Both McCarrison's statistics
for man in Chitral and Gilgit and our own for fish reach well into the period of increasing
incidence of neoplasms in mammals.
HEMOGLOBIN ESTIMATIONS.
In the autumn of 1902, before thyroid carcinoma in fishes had attracted attention
in this country, one of us observed, incidental to work upon bacterial infection in trout,
an anemic condition among a certain lot of brook trout at a State hatchery at Paris,
Mich. These fish were i^ years old and were part of a lot of several hundred which
had been sorted and segregated from the general hatchery stock on account of their
undersized and stunted condition. Except for their small size this lot was in fair
condition and most of them would have spawned for the first time some weeks subse-
quent to these observations. Of this selected lot the percentage having tumors was
not determined but there were more normal healthy fish than those bearing tumors.
Even the tumor fish with anemia showed no particular emaciation or falling off in
condition.
Nine apparently healthy fish without tumors were taken at random from this lot
and hemoglobin readings obtained. Nineteen tumor fish from the same lot then had
their hemoglobin estimated in the same way. The range of the former was from 30 to
43, of the latter from almost nothing 1047, the averages being 37.5 and 21.6, respectively.
The readings were made with a Dare hemoglobinometer; those recorded as 8 are arbi-
trarily overstated, the samples scarcely showing red and registering much below the
lowest scale reading. The fish showing the highest reading (47) had only a very small
tumor, in the jugular pit. The largest fish of the series (first of the table) showed one
of the lowest readings, and had marked blood changes. The tumors were not measured
or accurately compared, but the larger usually gave the lowest readings. A marked
poikilocytosis accompanied a low blood count for red cells. The normal red cells
numbered 256,000 per cubic millimeter, or 416,000 including the atypical reds of extra-
ordinarily small size. The red cells of normal brook trout blood number about i ,000,000
per cubic millimeter.
448
BULLETIN OF THE BUREAU OF FISHERIES.
While tumor fish not infrequently have blood infections, plates made from the heart
blood of several of these tumor fish remained sterile, save in one case. The hemoglobin
readings and other data for each individual are given in the following table :
TABLE VI.— HEMOGLOBIN ESTIMATIONS ON THE BLOOD OF TROUT AT THE STATE HATCHERY AT
PARIS, MICH., IN OCTOBER, 1902.
Sex.
Length.
Hemo-
globin, o
Sex.
Length.
Hemo-
globin. 6
CLEAN FISH.
Mate
Centi-
meter .
5
TUMOR FISH.
Male
Centi-
meters.
20
Do
38
Do
16
36
Do
16
Do
Do
16
Do
Do
16
Do.. .
38
Do
15
28
Do
Female
16
g
Do
18
8
Do
Do
Do
10
i
i
z
i
i
i
i
19
ii
27
8
8
18
8
29
Average 37.5.
6 Average 21.6.
SPONTANEOUS RECOVERY.
In the microscopic examination of sections of carcinoma of the thyroid at Craig
Brook station during the summer of 1909, we occasionally encountered what appeared
to us to be evidences of regression in certain tumors. We therefore were led to look
for evidences of spontaneous recovery. To determine whether a change to more favor-
able conditions on the part of the fish would increase the number of spontaneous recov-
eries, in the autumn of 1909, 119 fish with visible tumors, mostly of large size, were
selected from a lot of landlocked salmon (lot 1950), and placed in pond i at Craig
Brook station. During the winter of 1909-10 two yearling brook trout with small
thyroid tumors visible at the isthmus were held without food in a glass jar in the cold
with occasional changes of water. One died after a few weeks with the tumor still
visible. During 44 days the tumor of the other fish disappeared entirely, leaving the
entire thyroid region without external enlargement. In the early spring' of 1910 an
examination of the 119 tumor-bearing fish in pond i was made to determine to what
extent spontaneous recovery might have affected this advanced lot. The conditions
in the pond were more favorable than in the pond below. Here the fish received pure
water directly from a spring, had access to natural vegetation, and obtained from their
surroundings some natural food while they were fed very little artificial food. Thus
they were in a large degree removed from fish culture. During a year the loss was
67 per cent and of the remaining fish only 56 per cent showed visible tumors.
CARCINOMA OF THE THYROID IN SAUMONOID FISHES. 449
Aside from the actually observed subsidence of visible tumors under some abate-
ment of the conditions of domestication, trout taken at random from fish-cultural ponds,
with clean thyroid region, show the usual microscopic picture associated with thyroid
known to have recovered from tumor formation. The wild trout used in feeding experi-
ments showed numerous examples of this sort. (Fig. 91-92.) That trout can recover
under apparently the same conditions under which they acquire the disease, and under
which other trout are showing progressive tumors, seems sufficiently attested by our
experience.
Recognition of spontaneous recovery is a necessary factor in studying the controls
of fish treated with various metals. It is a remarkable fact that in only three or four
instances in a total of 46 controls did we find spontaneous recovery under the conditions
selected for these experiments. Regression does not appear to occur until after the dis-
ease has continued for some time. The best evidence of regression from moderate hyper-
plasia is found in the wild Wisconsin brook trout with selected feeding, in tanks i and 2
containing lots 2146 and 2147. (See table vm, p. 100.)
In this experiment at the end of one year, fish fed upon raw liver and raw ox heart
showed marked hyperplasia, whereas those fed upon various other types of food showed
no evidence of hyperplasia. At the end of two years the only lots of fish remaining free
from evidence of hyperplasia were those fed upon natural food (i. e., live maggots, fresh
water and salt water mussels, etc.), whereas those which had from the beginning been
fed upon raw liver or raw ox heart in the various experiments, showed a few individuals
with well-developed visible tumors and a large number with well-defined evidences of
retrograding hyperplasia. A microscopic examination of various fish from these lots
will serve to characterize the changes which indicate regression of the earlier stages of
the disease. See 2099, 2101, 2103, 2104, on pages 101 and 102.
Summed up, these changes are the evidences of an increased amount of thyroid
tissue indicated by the presence of follicles in regions in which they do not normally
occur. The follicles are not closely packed as in active hyperplasia, there is no evidence
of hyperemia, there is a well-defined stroma, the stroma often forming trabeculae between
the alveoli as wide or often wider than the diameter of the follicles. The follicles them-
selves show great variety in size, a few larger ones are filled with stainable colloid, but
the majority of them are small, of irregular shape and free from colloid or are but partly
filled with poorly stainable colloid. The epithelium is flattened, often definitely atrophic,
the protoplasm greatly reduced in amount, so that the cells are composed for the great
part of their nuclei, which stain homogeneously and deeply. (Fig. 91.) Frequently
evidences of there having been more than one layer of epithelium may be found. The
greatest changes are in the peripheral regions, which is characteristic of the regression
of all neoplasms. The evidence of the previous branching and irregular tubular type
of proliferation, which characterizes the growing tumor, are found in atrophic struc-
tures of tubular and branching shape, sometimes reduced to a mere cord of cells. (See
fig. 92.)
From a survey of such specimens it is clear that an actual disappearance of thyroid
tissue must have taken place. In the earlier stages of regression from large tumors
450 BULLETIN Of THE BUREAU OP FISHERIES.
evidences of extensive hemorrhage are found, a characteristic which also distinguishes
regression following treatment with metals. In such cases organization of the areas of
hemorrhage by connective tissue appears. (Fig. 101.) In the earlier stages of regression
the periphery of the tumor will frequently show evidences of round-celled infiltration
in the stroma. The scirrhous appearance of advanced tumors which have undergone re-
gression is distinctly characteristic. It will be seen that these changes are distinct from
the changes following so-called resolution of hyperplastic thyroid which leads to the
stage of colloid goiter, as observed in the Scotch sea trout, where the terminal stage of
simple hyperplasia is the large follicles filled with stainable colloid, lined by flattened
epithelium. (Fig. 22.) The changes here described as regressive are of the same nature
as those encountered in the regression of transplanted or spontaneous carcinoma of the
breast in mice. (Gaylord and Clowes, 1906.) The microscopic picture of retrograding
large tumors in no way differs from the changes following regression by treatment with
iodine, arsenic, or mercury, except that no doubt in the latter instance the changes pro-
ceed more rapidly and with less evidence of stroma formation. (Fig. 109.)
IMMUNITY.
Among marine species it has been remarked that the chinook salmon held at the
Craig Brook station until 3 years of age were entirely immune to visible thyroid growth.
These fish were nevertheless in poor condition, and did not grow and thrive normally.
This fish is anadromous, and under natural conditions the young, being hatched in fresh
water, soon find their way to sea. Notwithstanding this, they may survive and grow
to maturity when held captive in fresh water. It might be inferred that the immunity
which resides in marine species of salmonoids, or the protection which the sea affords
them — no marine species having been found in the sea with thyroid enlargement — is
transmitted through the eggs and continued during a prolonged sojourn in fresh water.
But the humpback salmon is likewise a Pacific marine species, and yearlings of this kind
produced at Craig Brook are fine examples of thyroid tumors. Of 319 fish (lot 1986)
about i year old, 14 per cent bore tumors when examined in April. By the following
August only 79 fish remained, of which 84.8 per cent had tumors. These resembled the
tumors of the Pacific hybrid salmon and showed the same structural evidence of malig-
nancy. Wilkie reported (Gilruth, 1902) a thyroid tumor in a 5-year-old Atlantic sal-
mon in fresh water in the ponds of the Clinton hatchery, New Zealand, and we have
seen one example at the Craig Brook hatchery in Maine. It is evident that marine
species may develop thyroid carcinoma while resident in fresh water.
The best example of species immunity is afforded by the Scotch sea trout, which at
Craig Brook is almost completely immune either to visible or microscopic enlargement.
One doubtful case of a distinct tumor is recorded and several of red floors, at 3,4, and 5
years of age. Doubtless trout of this species can not continue indefinitely without
affection under the conditions which produce the disease.
While the Pacific salmon hybrids all show a high susceptibility, other hybrids and
the brook trout species exhibit various degrees of susceptibility and immunity to tumor
formation. The landlocked salmon is about as susceptible as the brook trout, but lot
CARCINOMA OF THE THYROID IN SAI^MONOID FISHES. 451
1944 showed no visible evidence of thyroid disease until the fourth year, though living
under the conditions which produced the disease. Lot 2017, hybrids of the brook trout
and landlocked salmon, when it consisted of 1,553 yearling fish, showed not a single fish
with a visible process. In the second and fourth years a few visible growths appeared.
A lot (2133) of rainbow trout, which develops frequent and large tumors at some hatch-
eries, were held two years at the Craig Brook station without acquiring any visible
tumors and only a small percentage of red floors.
As previously referred to, rainbow trout at the Caledonia hatchery in New York
appeared to have a very low incidence of the disease, about one-half of i per cent of the
fish each year showing well-developed tumors, this covering a period of approximately
25 years. As stated, no fresh blood during that period was added to this lot of fish.
Tumor fish found each year were destroyed and a probable original resistance of the lot
was protected and perhaps added to by this form of selection, so that, as we have pointed
out, in the epidemic at the Bath fish hatchery covering a period of two years these fish
remained practically immune, only i or 2 fish in a lot of 75 adult fish being found with
tumors in the course of the two- years' epidemic. Exactly the same state of affairs
existed in a lot of 20,000 German brown trout which had also been held without the
addition of fresh blood at the Caledonia hatchery. These were represented among
others by some 200 of their offspring, which as 4 and 5 year old fish went through the
epidemic without a single tumor. This was not the case with some 4,000 young German
brown trout which were sent from the Caledonia hatchery to the Bath hatchery as
young fish, and which toward the end of the epidemic, as 2-year-old fish, developed a
considerable incidence of the disease.
That the rainbow and brown trout retained so *nany years at the Caledonia hatchery
really possessed a definite immunity against the disease is shown by the fact that during
this time attempts to rear brook trout to adult age and maintain them resulted in a high
incidence of thyroid tumors in this species. That a given lot of fish from one hatch may
possess at a certain age an almost complete resistance to the disease, while another lot
from another hatch of the same species and of the same age, kept under the same condi-
tions, may show a high incidence of the disease, is possibly explainable on the basis of
blood relationship. The manner in which spawn and eggs are taken and fertilized
would easily bring about the presence in any given lot of a large number of fish with the
same parents. With the exception possibly of the hybrids, some of the lots of which
were small, no lot of fish which we have studied could possibly be entirely of the same
parentage; but as a large number of individuals in each lot are certainly of the same
parentage it is explainable that the high degree of immunity or susceptibility in a given
lot may be due to this fact. Such a supposition is in accord with the now well-known
facts of family predisposition in both goiter and cancer in human beings.
The fish offer a remarkable opportunity for the careful study of this phase of
immunity. It will be easily possible to obtain in any hatchery in which the disease
is endemic, on the one hand from parents both having visible tumors, or, on the other,
from parents showing distinct immunity, a sufficient number of eggs to hatch several
hundred fish. A number of fish could be reared from such lots sufficient to demon-
452 BULLETIN OF THE BUREAU OF FISHERIES.
strate clearly in a few generations the exact importance of blood relationship to sus-
ceptibility and immunity. To guard against possible accidents obviously a series of
such experiments should be carried on at the same time and to this purpose it would
be necessary to devote the entire activities of a fish-cultural station for a period of years.
The importance of such ah investigation to the question of immunity in goiter
and cancer would certainly justify such an undertaking, aside from the possibility of
practical results to fish culture. Only in this way can the importance of inbreed-
ing as practiced in fish culture in the production of a general susceptibility among
domesticated fish to this disease be properly determined. It is a common assumption
that hatchery fish are more or less inbred. We have emphasized this idea in our
earlier statements. A marked susceptibility of at least one lot of pure marine salmon
species, i. e., the humpback, and in fact the occasional occurrence of the disease in
wild fish, indicate that inbreeding as such, except by the perpetuation and accentua-
tion of such susceptibility, may not be considered an important factor and the facts
developed in connection with the rainbow and brown trout at Caledonia clearly show-
that fish-cultural inbreeding may finally develop a markedly resistant strain.
To what extent spontaneous recovery from the disease results in acquired immunity
is not easy to state. There are many facts in this investigation which indicate strongly
that recovered fish remain immune for a considerable period of time if not indefinitely.
An experiment to determine definitely this question, although carried out with too
few individuals, failed to realize the development of visible tumors in recovered fish
at the end of one year, although placed in one of the lowermost ponds where the inci-
dence of the disease continued to be high.
McCarrison (1906), in his study of endemic goiter in the Chitral and Gilgit Valleys,
gives striking examples of family predisposition to goiter and refers to the frequent
occurrence of goiter in nursing children where the mother has the disease. Schittenhelm
and Weichardt (1912), in their recent monograph on endemic goiter in Bavaria, state
that it is easy to trace family predisposition to goiter and append family trees of some
1 3 families, from which it may be readily seen that certain families show a remarkable
incidence of the disease, which is especially marked in children where one or both parents,
and especially when both parents and grandparents, are affected by goiter. There
are several experimental studies in the lower animals indicating family susceptibility
to cancer, the most striking being the breeding experiments of Dr. Maud Slye (1913),
and recent statistics emphasize the well-known fact of family predisposition to cancer
in human beings. Racial immunity to cancer has been shown by Levin (1910) to be
very marked in the American Indians. This fact applies to isolated tribes of Indians
living upon reservations extending from the northern to the southern limits of the
United States, where the Indians for a period of 20 years have shown almost complete
immunity to cancer, whereas the whites living in the immediate neighborhood show
the usual incidence of cancer characteristic of the white inhabitants of the country.
That such immunity is a special immunity to cancer and not a general resistance to
disease is indicated by the fact that the same tribes of Indians show an unusually high
mortality from tuberculosis.
CARCINOMA OF THE THYROID IN SALMONOID FISHES. 453
EXPERIMENTAL PRODUCTION OF THE DISEASE.
TROUT TUMOR MATERIAL IN STANDING WATER.
The contents of a thyroid tumor of a trout were expressed into tap water and brook
trout fry in the sac stage were introduced. About 300 fry were used, distributed in 15
shallow open dishes each with from i to 2 liters of the contaminated water. Eighty-
five fry in similar dishes constituted the control. By keeping the dishes in the cold the
fry were maintained for 23 days without change of water, or other than spontaneous
surface aeration. During this period a loss of 16 per cent occurred on the fish in the
tumor water and 11.7 per cent on the controls.
After removal from the tumor water the fry and their controls were held for sev-
eral weeks in flowing tap water and suffered a gradual mortality. Sections of the thyroid
region of these fish show no recognizable difference between the controls and those fed
the thyroid material. Figure 13 shows the thyroid of a control fish soon after the food
sac had been absorbed.
FEEDING TROUT THYROID TUMOR.
Fourteen brook trout of yearling age but of small size, reared almost entirely on
live fish food, were fed nine times during one month with portions of fresh thyroid trout
tumor. The fish were held for 54 days in glass jars, containing each 3 liters of water
and two individuals. The water was changed once during this period. The tempera-
ture ranged from a little above the freezing point to 17° C., which made necessary their
removal to flowing water. They had received no other food than tumor material.
When transferred there was no external evidence of thyroid enlargement. No histo-
logical changes in the thyroid tissue were recognized after careful comparisons with the
controls.
FEEDING HUMAN CANCER LIVER.
Under the same general conditions as in the preceding experiment 12 trout were
fed five times during 23 days with solid human cancer material from metastatic foci in
liver of gastric carcinoma. After 54 days they were transferred to flowing water. All
were without externally visible thyroid change and showed microscopically the same
early hyperplastic stage as the controls.
CLOSED CIRCULATION.
In order to experiment further with normal and tumored trout in unchanged water,
two independent aquarium systems were established for using the same water over
again continuously by means of circulation, aeration, and filtration. Refrigeration was
also provided so that the water could be at all times kept at a suitable temperature for
trout.
During 5 1 days, 1 6 domesticated brook trout were fed human cancer of the liver on
14 different days, and became reduced to 8 fish in number. The thyroids of 4 of these
were affected and 2 had visible tumors, but an accident prevented the controls from
covering an equal period, and though the latter, 12 in number, were all clean but one,
nothing conclusive is to be inferred.
454 BULLETIN OP THE BUREAU OF FISHERIES.
Fifty clean domesticated yearling brook trout were placed in the closed circulation
with several badly tumored trout. In over four months, during a large part of which
the water was aerated artificially, without circulation, we did not succeed in producing
any notable thyroid reaction, and none which went beyond the controls. We do not
believe tumors can be produced by contact or association with tumored fish in this way,
at least not in any reasonable time. (See also feeding experiments p. 100.).
The experiments in the closed circulation add to those in standing water in glass
dishes in showing that the pollution of the water by the fishes themselves and their
food refuse plays little if any part in the thyroid reaction. A number of trout were held
for 113 days in a 63-gallon aquarium tank with only four changes of water. Artificial
aeration was maintained by a constant air current liberated in minute bubbles at the
bottom of the tank. The fish were domesticated yearling trout, but not of a readily
susceptible lot, and none of them showed any external sign of thyroid change at the end
of the experiment. The fish were fed on liver, ate heartily, and were in good condition
thoughout the period.
Most brook trout, however, held in troughs at the laboratory and supplied with
Lake Erie water tended to acquire the red floor of the mouth when fed on liver. Such
trout kept in the ice-cold tap water in the winter and fed nothing, or given very low
feeding, showed within a few weeks signs of thyroid regression. Further evidence of
such regression is afforded by a yearling brook trout with a small but distinct thyroid
tumor visible at the isthmus. It was placed in a glass jar with standing water in the
cold and kept for 44 days without food. The water was changed several times. The
tumor had completely disappeared at the end of this period.
TRANSPLANTATION AND INOCULATION EXPERIMENTS.
Several attempts to secure a new autonomous growth by implanting portions of
visible thyroid tumors in normal trout have been made. Both wild and domesticated
trout have been used. In only one fish have we met with partial success in that the
graft showed evidence of proliferation and was still alive at the end of three months
when examined microscopically.
In December, 1908, a number of supposedly healthy fish were sent to Buffalo from
St. Johnsbury, Vt. These were inoculated in the thyroid region with a suspension of
thyroid tumors from fish obtained from Bath. The surface of the tumor was carefully
sterilized by burning. The greatest precautions were taken to prevent contamination.
The center of the soft tumor was carefully scraped out, rubbed up with salt solution,
and then injected. Nineteen fish were thus inoculated and later transferred to the
Bath hatchery, where they were kept in the troughs of the fish-hatchery building. An
examination of these fish in the autumn of 1909 showed that all of them had visible
tumors, but the epidemic of 1909 was at that time in full swing, and it was impossible
to determine whether the development of tumors was due to the inoculation or to the
simple fact that these fish had been placed in the infected water of the Bath fish hatchery.
In a series of fish inoculated at Bath in the summer of 1909, in most of which the
grafts were contaminated and sloughed out, one fish (no. 83), which was inoculated Sep-
CARCINOMA OF THE THYROID IN SALMONOID FISHES. 455
tember i, 1909, and killed for examination November 24, 1909, showed at the point of
inoculation, which was in the muscular structure of the abdominal wall, just anterior to
the left ventral fin, evidence of a small protruding growth the size of a grain of rice. On
sectioning this tissue, a slender growth is found extending in what must have been the
track of the needle. Under the microscope the growth is made up of a series of nodules,
most of them with a not very well-defined connective tissue capsule. The continuity
of the epidermis at the point of the small tumor is broken, and we have here a growth of
tissue connected with the nodular growths in the deeper structures. This protrudes
through the broken continuity of the epidermis. The circumscribed nodules lying be-
tween the muscle bundles and the subcutaneous tissue are made up of large spindle
and irregularly shaped cells. The centers of the larger nodules contain a certain amount
of hyaline detritus. Scattered between the cells of the nodules, particularly toward the
center, are many leucocytes. At the outer margins of the nodules the cells are best
preserved. The nuclei vary greatly in size, the protoplasm stains, the cell boundaries
are not always well defined. The growth is made up of a complex of cells with large
vesicular nuclei containing one or more nucleoli. They may be recognized as thyroid epi-
thelium. In a nodule which fills the break in continuity in the epidermis there is a dis-
tinct suggestion of tubular arrangement with a definite stroma carrying blood vessels,
and at the margin of one or two of the other nodules definite alveoli may be made out.
Toward the centers of the nodules there is distinct evidence of atrophy of the cells,
associated with clumps of chromatin and hyaline detritus. There are many cells with
very large nuclei. There is generally a great difference in the size and shape of the
nuclei. Rarely a karyokinetic figure is found. The cells are closely packed together,
but in some nodules there has evidently been a growth of capillaries in attempts at forma-
tion of a stroma. From the microscopic picture it is evident that there has been some
proliferation in the implanted tissue, and that three months after portions of the graft
at least are still alive.
At Craig Brook station in 1910 implants were made directly into the thyroid region
of the fish with the aid of a hypodermic needle. It was found that the trout will endure
a needle puncture in the floor of the mouth and the injection of one-fifth cubic centimeter
of physiological salt solution directly into the tissues containing the thyroid with little
reaction. By inserting the needle a little to one side of the median line the ventral
aorta is avoided, and most of them show no external bleeding. Some of the fish suffer
from shock, due to the puncture, from which they recover within 5 to 20 seconds. Even
those which bleed usually do not succumb. Of 76 yearling domesticated trout thus
inoculated as controls, only i died as a result of the manipulation. The fish tumor
material for inoculation was ground up and mixed with its own volume of physiological
salt solution. The difficulty in planting this material in the tissues of the trout lies in
the high toxicity of the tumor extract. It is not practicable to place transplants of
ordinary size in this vascular region without heavy loss from toxemia. The tumor
material varies considerably in toxicity. Domesticated trout endure the mechanical
injury incidental to inoculation better than wild trout.
BULLETIN OF THE BUREAU OF FISHERIES.
Of 30 wild trout injected in the thyroid region with 2 minims each of tumor
ground with an equal volume of salt solution, about half died from the immediate toxic
effect of the injection. At another trial one-tenth cubic centimeter of material made
from several tumors was injected into each of 15 domesticated trout. Eleven of them
succumbed almost immediately. The material was then diluted until it contained 3
volumes of salt solution and 15 more fish were injected, but 12 of these died within 2 or
3 hours. Seven fish were injected subcutaneously near the dorsal fin with one-fifth
cubic centimeter of this material, and 5 died within a short time. One cubic centimeter
was, however, passed into the stomach of i trout, and one-half cubic centimeter each
into the stomachs of 3 others without apparent effect. This particular sample of com-
bined tumor substance was unusually toxic.
The trout dying from the immediate physiological effect of trout tumor substance
ground with salt solution showed a fairly characteristic picture of symptoms, ending in
tetany. The mechanical effect is little, as shown by the control fish. In the few
cases where the shock from trauma is apparent the fish lies on its back or side, scarcely
breathing, and recovers in a few seconds. The inoculated fish, however, were evidently
poisoned. They became immediately distressed, swam in circles or in short, frantic,
and aimless dashes about the trough, then fell greatly weakened upon their sides and
lay there with short and rapid breathing until the next paroxysm. Finally they suc-
cumbed in tetany, some with gills widely distended and marked opisthotonos. Even
the survivors seemed to be much weakened.
Forty-three wild brook trout were inoculated in the thyroid region with small
portions of tumor taken directly from the fish without grinding or mixing with salt
solution. Pieces were forced through the floor of the mouth by means of trochar, probe, or
seeker. The material was more or less toxic even in this form, and the mechanical injury
and bleeding were greater than with the needle, but 24 of the 43 trout survived.
Ten domesticated brook trout were injected in the thyroid region with one-fifth of a
cubic centimeter each of a mixture of one volume of domesticated brook trout blood
and three volumes of physiological solution. No loss attended the operation, and the
fish have never shown any but the immediate reaction to the inoculation.
In all injections and inoculations the instruments used were sterile, and the tumor
material obtained as free from contamination as possible. It is not usually possible to
obtain in quantity the thyroid tumor material from fish in a completely aseptic condition.
Mud from one of the fish ponds (no. 10) constantly associated with tumor fish was
injected into the stomachs of 25 domesticated trout and of 20 wild trout. The dose
was repeated on the former lot after three days. The filtrate of this mud through paper
was injected into the thyroid region of 25 domesticated trout and behind the eyeball
of 17 domesticated trout. The dose was 2 to 2^3 minims. These fish have shown no
results from the inoculations.
Trout tumor material has been ground with sand and filtered through a Berkfeld
filter. The filtrate has been injected into the thyroid region of 2-year-old domesticated
trout, all manipulations being carried on in the cold. About 0.3 to 0.4 cubic centimeter
of filtrate was given each of 9 trout. These were kept under observation for over four
CARCINOMA OF THE THYROID IN SALMONOID FISHES. 457
months, when one thyroid tumor and two red floors had developed among them. The
controls had been previously lost from some unknown cause, leaving the result negative.
EXPERIMENTAL INDUCTION OF CARCINOMA."
In June, 1910, about 2,400 wild brook trout of various sizes were collected in the
wilderness of Wisconsin by the Bureau of Fisheries and brought to Craig Brook station.
They were held in Craig Brook above all fish cultural operations until used in experi-
ments. Several specimens were sectioned from time to time and found to be entirely
normal. A series of 16 new cement tanks, 2.7 by i by i meters in size, which had not
previously held fish, were used as containers for the experimental lots. (Fig. 79 left.)
The depth of water in these tanks was 0.8 meter and the inflow 50 to 60 liters per
minute. In July, 1910, n lots each of 50 adult wild trout from Wisconsin were placed
in 1 1 of these tanks and feeding experiments begun with a variety of foods, which were
maintained for each lot throughout the experiment without change. The so-called
natural food was not all of one kind, but consisted of fresh-water mussels, fresh-water
fish, and in the summer maggots of flies. The vegetable food was screenings from
miscellaneous grains. In September, 1910, certain of the lots were augmented by smaller
wild trout from Wisconsin, which had received food corresponding to the lots to which
they were added, or natural food.
Table vm summarizes these feeding experiments and includes some smaller lots
which were inoculated in various ways, and were fed natural food. Such lots were
negative, and are in effect controls to the feeding experiments. The inoculated lots
are discussed under a separate heading. Lot 2149 was an attempt to crowd the fish
by confining them in one-third of the tank. Lot 2155 aimed at excess feeding.
Lots 2150 and 2151 were practically wiped out by the unsuitable food, to which the
wild trout could not adapt themselves readily. The wild trout gradually became
accustomed to the fish cultural foods, liver and heart, and finally thrived upon them
about as domesticated trout do. On examination after four months, and again after
one year, all the fish were clinically clean, without any external evidence of thyroid
disease. At the examination after one year the thyroid region of from one to three
fish from each tank was prepared for microscopic study, and the histology of each is
shown below by a description of each section by number (table vm). The diagnoses may
be briefly summarized as follows:
In the lots fed raw liver (fig. 84) and heart (fig. 85) a general hyperplasia existed
with early carcinoma in a few cases; the two fish from lot 2155 were exceptional, appear-
ing normal. The lot fed cooked liver had remained normal. (Fig. 87.) Those fed
marine fish (fig. 88), vegetable food (fig. 89), and natural food (fig. 86) were entirely
without hyperplasia. Nearly all remained normal, but a few showed a considerable
» We believe that these experiments, reported at the fifth annual meeting of the American Association for Cancer Research,
Aprils and 4, 1912, in Philadelphia, and reported in the Zeitschrift f iir Krebsforschung. Band 12, Heft a, 1912, p. 436, under the
title, " Relation of Feeding to Thyroid Hyperplasia in the Sahnonidae," by H. R. Gaylord and M. C. Marsh, Buffalo, constitute
the first instance in which spontaneous cancer has been experimentally induced tinder properly controlled conditions in the
lower animals. They antedate the recent experiments of Fibiger in the production of carcinoma of the stomach and esophagus
in rats by feeding them nematodes from cockroaches, for which a similar claim has been made.
8207°— 14 7
458 BULLETIN OF THE BUREAU OF FISHERIES.
increase in the number of thyroid follicles without elevation of epithelium or other
changes from the normal. Lot 2163 was exceptional in that two of three fish showed
beginning hyperplasia. They had been inoculated with trout tumor material in the
thyroid region, the implant failing to take.
At the examination of June, 1912, two years after the beginning of the experiment,
one distinct thyroid tumor (fig. 90) had developed in lot 2146 under the feeding of raw
heart muscle. This fish, and one lot 2147, which was fed raw liver and had developed
a red floor, with slight swelling, showed typical thyroid carcinoma. Of the rest many
had developed red floors, as shown in table vin. One or more specimens were preserved
from each lot, and a description of the histology of the thyroid is given below. The
trout fed with marine fish, vegetable, and natural food still remained normal, while carci-
noma has definitely developed in two of the sample fish fed raw animal food. Those fed
cooked liver have passed through hyperplasia to regression and, in fact, the chief char-
acteristic of the microscopic picture in all the fish on meat diet is the regression indi-
cative of spontaneous recovery. (Fig. 91-92.)
In general, it may be stated that the results obtained by selected feeding are in
accord with our experiences in the study of hatchery conditions and that the relation
of foodstuffs to the incidence of the disease is contributory and not causative. Thus
raw liver and raw ox heart used as a food act as a predisposing factor in the develop-
ment of carcinoma of the thyroid. Cooking the same food tends to delay the advent
of the disease and fish fed upon natural food, marine fish, and vegetable food are able
to resist the disease for a considerable period of time, if not indefinitely. One might
conclude from these experiments that raw liver and raw heart muscle were the sole
cause of the disease, were it not for the fact that we are able to check this observation
by an observation made at another hatchery where the conditions are practically
reversed. In this hatchery all of the fish are fed upon raw liver and raw ox heart muscle;
but the fish kept in one water supply are free from the disease with this type of feeding,
whereas those kept in other tanks with a slightly different water supply are uniformly
affected by the disease. This state of affairs exists at Cold Spring Harbor, N. Y. The
hatchery building is supplied with water from an artesian pipe driven near the building.
The overflow from the hatchery, and, of course, from the artesian supply, which is not
required for the hatchery building, flow into a series of large earth ponds, and then
a series of concrete-lined ponds. The arrangement of the concrete ponds is such that
one pond is practically continuous, each division for fish being separated from the one
above it by an arrangement of boards over which the water flows. The ponds and
concrete tanks are old and at the time of examination were lined with a visible growth
of green algae.
Young fish hatched in the hatchery in the artesian water were placed for the most
part in the concrete tanks just mentioned, but in a few instances the lots were divided
and approximately half were placed in a spring located a distance of several hundred
yards from the hatchery building. This spring flowed out from a hillside obviously
from the same general supply as the artesian water and the springs near the hatchery.
CARCINOMA OF THE THYROID IN SAI.MONOID FISHES. 459
In the small brook about 100 yards in length wooden divisions and tank-like arrange-
ments had been constructed. In these the young fish were placed and all the fish both
in the old concrete tanks and in the spring were fed with chopped raw beef liver and
ox heart muscle. An examination of specimens taken from the two sources in the
autumn of 1911, of fish respectively 6 and 18 months old, taken from both sources,
showed that whereas the fish in the old concrete ponds had well-defined hyperplasia
(fig. 93), those kept in the spring water had thyroids exactly like those found in wild
fish (fig. 94), although both had been liberally fed upon raw liver and ox heart. From
this observation we must conclude that the selective feeding experiments at Craig
Brook station indicate that the feeding of raw ox heart and liver produce conditions
either in the tanks or in the fish themselves which favor the development of the disease,
but that such feeding of raw heart muscle and liver is not the direct cause of the disease.
It is hard to understand why fish fed upon cooked liver should have resisted the disease
so much longer than those fed upon the uncooked liver, unless it is possible that the
agent causing the disease is sometimes or usually transmitted with the uncooked
materials, or that cooking the material delays decomposition and thus favors a more
hygienic condition in the tanks. The complete resistance of fish fed upon natural
food, chopped marine fish, and vegetable food, all of which were obtained from sources
entirely different from either the heart muscle or liver, would rather suggest that these
sources of food are free from the possible contamination with the agent of the disease ;
or, again, that they are not so easily decomposed in the tanks and do not therefore
contribute to a favorable condition for the propagation or development of the agent
in the tanks.
McCarrison (1906) points out that in Chitral where goiter is endemic the people
are for the most part poor. Food is plentiful, comparatively speaking, from July to
February, after which the people are obliged to live on the poorest grains, dried fruits,
and the green stuffs of the spring. Their food is entirely vegetable. Flesh meat is an
article of diet far beyond their means, while salt is a luxury to all except the richest
families.
That the disease may be introduced into a community where it has not previously
been and that in such cases the water supply becomes at once the suspected agent of
distribution is shown by McCarrison's remarkable observation in Nagar.
In the village of Nagar goiter was unknown six years ago. Nagar is a small State situated up one
of the many side valleys on the left bank of the Gilgit River. It will be remembered as the scene of a
smart frontier rising in 1893. It was after this year that the little State of Nagar began to be opened up;
previously, jealous of its independence and at war with its immediate neighbors, it was careful to
exclude foreigners. During recent years intercourse with the outside world has become more free,
but still there is a decided prejudice against the settling of foreigners in this little hill State.
Some five years ago certain cases of goiter were introduced from without, and since then the disease
has begun to gain a footing. It may be as well to indicate clearly that there can be no doubt about
the fact that goiter was quite unknown six years ago. The fact that it has gained a footing in his territory
is a matter of very considerable anxiety to the present rajah, and through his help I was enabled to go
into the matter with great care. All the important men of the State, the rajah himself, councilors,
priests, etc., assure me that no case of goiter ever originated in Nagar till within the last six years.
460 BULLETIN OP THE BUREAU OP FISHERIES.
There is a family at present at Nagar which consists of nine souls; of these three came from Gilgit
some years ago, all suffering from goiter. Two, the father and the mother, have no goiters; the father
came from Gilgit. The remaining four individuals have never been outside Nagar. Three are high-
caste Mohammedan girls (16, 15, and 10 years of age), which makes the statement the more likely to be
accurate. The fourth individual is a, boy aged 12; he has never been outside Nagar. All of these four
developed goiter about two years ago. This family lives in the same house, that is, the same room,
eat out of the same vessels, etc. It is to be observed that these, the first victims, are all young.
Another family consists of a man, his wife, and son, aged 2, and the man's brother, aged 20. The
man brought goiter with him from outside five years ago. Two years later his brother developed the
disease, though he had not been outside Nagar for five years. The little boy, aged 2, developed the
disease one year ago; the wife is free from it. Another man, aged 23, brought the disease from Gilgit
one year ago; it is increasing in size here.
Twelve children, all under 10 years of age, were brought to me having marked enlargements of the
gland. There are no other cases of the disease in Nagar. The children were from different houses
scattered over the village. The first family to which I referred lives at the head of the spring which
supplies the village with drinking water.
The village supply consists of a spring which comes out of the hills; it is not the only supply of the
village. The cases I have referred to all drank from this water. This spring is said to have been in
existence from time immemorial; the chemical composition of its water has presumably not altered.
The conditions of life of the people are the same. The only added factor in the case is the introduction
of the disease from without. That it is spreading there can be no doubt, and that the course of the spread
is a typically endemic one is equally evident. It is easy to understand why the disease should not
have reached Nagar earlier, as it is only within recent years that the communications of Nagar with the
outside world have become free.
It appears evident also that it is by means of the spring water that the disease is now spreading,
for the 12 children are residents of that part of Nagar supplied by the spring, and their homes are scat-
tered here and there among the houses of the yet unaffected inhabitants. Further, the fact that the
first family referred to lives at the head of the spring is of importance, and also that no cases of this
disease were observed where water from other sources only is drunk, that is, in the distant parts of the
village where the nullah water or the river water is used.
It seems likely, therefore, that some poison, goiter producing in its powers, has been introduced
into a water supply which happened to be suitable for the conveyance of this disease.
This case of Nagar can not be explained by any theory which attributes to dissolved ingredients
In a water goiter-producing properties; nor can inorganic matters in suspension account for this outbreak;
for it can not be supposed that from causes in the water which have existed from time immemorial a
disease should suddenly spring. There is, to my mind, only one explanation, namely, the introduction
of an organism into the water supply.
I
CARCINOMA OF THE THYROID IN SALMONOID FISHES.
TABLE VIII. — FEEDING AND OTHER EXPERIMENTS WITH WILD BROOK TROUT.
461
Tank.
Lot.
Fish.
Food.
Other conditions.
Fish
added
Sept. 21,
1910.
Clinical condition, June, 1913.0
Remain-
ing.
Clean.
With red
floors.
With tu-
mors.
2146
2147
2148
5°
50
Heart, raw. . .
0
27
5
14
4
0
25
7
o
13
26
o
o
o
o
0
o
J39
34
I
37
I
o
20
36
C»)
38
40
22
9
12
16
12
4
21
3°
o
26
I
17
4
i
ii
0
X
o
o
o
0
Liver, raw.
Marine fish . . .
4
2149
2150
5°
5°
Liver, raw. . . .
Vegetable
Reduced space; crowding
6
.do
In presence of tumor fish
2152
2153
5°
Liver, cooked .
Liver, raw .
16
28
4
8
0
0
o
0
o
o
0
0
o
o
0
8
In presence of tumor fish
9
10
II
2154
2155
2156
SO
5°
5°
Natural food. .
Liver, raw ....
Natural food . .
. do.. .
Minimum feeding
Forced feeding
Controls
PrmH in Trmrl in tank
35
40
21
S
12
15
9
3
3
o
i
4
o
i
3
I
13 upper.
13 lower . .
2160
16
.. do.. .
Controls for tanks 12-16
.... do....
Inoculated in thyroid r
with trout thyroid tumc
Pond 10 mud in stomachs
Inoculated in thyroid r
with trout thyroid tumc
Inoculated behind eye wi
trate from pond 10 mud
egion
r.
14
do
do
egion
r.
hfil-
16
2164
I?
do
Tank.
Sec-
tious,
1911.
Diagnoses, 1911.
Seo
tions,
1912.
Diagnoses, 1912.
20OO
2001
2O02
2003
A, h>
A, be
nor
Norrr
Begir
A, B
perplasia; B, ca
ginning hyperp
na.
al
2098
2099
2100
2IOI
2IO2
A, tumor, carcinoma; B, adeno-carcinoma.
A, B, C, regression.
Normal.
Regression.
Normal.
Regression.
A, B, regression.
Normal.
Regression.
Normal.
Increased thyroid of normal type.
Increased thyroid of normal type.
Normal.
A, normal; B, increased thyroid of normal type.
Increased thyroid of normal type.
Increased thyroid of normal type.
asia; B, normal; C, carci-
C, normal
6
2OO5
2OO6
2OO7
2008
Norrr.
A, B
A, B
A B
tal . ....
2103
2104
2113
2IO5
2IO6
2IO7
2108
2IO9
2110
2III
2112
8
beginning hyperplasia
C. normal. . .
A B, normal
B , C, normal
A, B, C. normal
13 upper.
13 lower . .
2OI2
2013
A, B
A, B,
normal
al
2015
2Ol6
A, no
Norm
rmal; B, C, beginning hyperplasia
al
16
Examinations of Nov. 30, 1910, and July, 1911, all were clean.
6 Transferred to pond 10.
DESCRIPTION OF SECTIONS TO ACCOMPANY TABLE VIII.
2000 B. Tubulo-alveolar type of carcinoma. Marked infiltration of surrounding areolar tissue. Infiltration of muscle above
into bone spaces and infiltration of vessel wall. Invasion of cartilage.
2001 A. Beginning hyperplastic stage. Certain follicles are lined with columnar epithelium. In many such follicles colloid is
absent, in others present but poorly stained. Surrounding this group of follicles are follicles of strictly normal appearance. Epi-
thelium flattened, filled with colloid. Beginning of the hyperplasia in this specimen is evidently limited to individual follicles
(Fig. 84.)
2001 B. Most of the thyroid tissue in this specimen is of typical normal appearance, flattened epithelium, follicles filled with
stainable colloid.
2001 C. The entire space surrounding the vessel is filled with closely packed alveoli, small sized alveolar structures lined with
high columnar epithelium, with deeply staining vesicular nuclei. Colloid is almost entirely absent. Evidently growth of the
thyroid tissue which has spread upward into the areolar tissue immediately below the mucosa of the floor of the mouth. Under
high power the nuclei present great variability in size, the staining qualities are vesicular with one or two nucleoli. Marked
evidence of hyperemia between the follicles. Many tubules are filled with closely packed cells. In some portions of the
growth all alveolar structure has disappeared and small islands of closely packed cells are found. Infiltration of dense con-
nective tissue structure, perichondrium and periosteum. Beginning carcinoma of tubulo-alveolar type.
462
BULLETIN OF THE BUREAU OF FISHERIES.
2002 B. The amount of thyroid tissue surrounding the vessels is very scarce. Vesicles small, epithelium flattened, filled •with
stainable colloid. Normal thyroid.
2003 A. Alveoli small and lined with high columnar epithelium, deeply staining nuclei. Colloid absent. Follicles few in
number and poorly staining. Occasional groups of vesicles of normal appearance. Beginning invasion of areolar tissue. Dense
connective tissue structure. Growth into bone cavities. Definite alveolo-tubular type beginning carcinoma.
2004 A, B, C. Space about vessels rather well filled with small-sized vesicles relatively uniform in size. Epithelium is flat.
tened. Vesicles are filled with stainable colloid. In one small area close to a large vessel area half dozen follicles in which the
colloid is small in amount, the epithelium cubical. Normal thyroid.
2005 A. This is evidently one of the tumor fish introduced into this experiment. Large amount of thyroid tissue. Great
variability in the size of the follicles. Large regular shaped follicles lined with flattened epithelium and filled with stainable colloid.
Large numbers of small follicles with cubical or flattened epithelium. Varying amount of colloid. Large amount of hyaline con-
nective tissue stroma. Obviously a tumor which has undergone regression. Tumor tissue fills the entire space around the vessel,
penetrates to the floor of the mouth, and into the bone cavities. It has previously invaded and destroyed large areas of muscle.
Contains numerous nematode tubercles, in which no worms are to be found. Spontaneous recovery. See further under that
heading.
2005 B. Very few follicles included in this section. Flattened epithelium filled with stainable colloid. Typical vesicles.
Normal.
2005 C. Evidently tumor fish introduced into this experiment with spontaneous recovery like 2005 A. Contains two nema-
tode tubercles, in one of which remnants of a worm can be seen.
2006 A, B. Thyroid consists of typical vesicles with flattened epithelium filled with stainable colloid. Normal.
2007 A. Space around the large vessels contains scattered follicles filled with stainable colloid, lined for the most part with
flattened epithelium. There is marked hyperemia, marked engorgement of the vessels between the follicles, and evidence of
small extravasation about the follicles. A few follicles are lined with cubical epithelium. Hyperemia of the thyroid, possibly
beginning hyperplasia.
2007 B. Tissue badly preserved, evidently overheated in embedding. Shows section of media of aorta around which are
areas of closely packed large follicles, lined with cubical epthelium. No colloid. Beginning hyperplasia.
2008 A, B. Small follicles lined with flattened epithelium, filled with stainable colloid. Normal.
2008 C. Thyroid tissue in this fish consists of rather compact masses in the region of the large vessels. The epithelium of
some follicles is slightly cubical. Follicles are filled with stainable colloid. Some evidence of hyperemia hi the vessels between
the follicles. Slight hyperemia of the thyroid. Probably normal.
2009 A, B. Follicles oval and spherical, lined with flattened epithelium, filled with stainable colloid. Normal.
2010 B. Vesicles lined with flattened epithelium, filled with stainable colloid. Normal. Around the large vessels the thyroid
follicles are closely packed; the colloid is reduced in amount but stains deeply. Epithelium is small, cubical. Probably normal.
Thyroid tissue greatly increased in amount but of normal appearance.
zoio C. Spherical and oval follicles lined with flattened epithelium filled with stainable colloid. Normal.
201 1 A. Follicles lined with flattened epithelium, filled with stainable colloid. Between the follicles hyperemia of the ves-
sels. Some evidence of extravasation. Hyperemia of the thyroid. Probably normal.
2011 B, C. Spherical and oval follicles lined with flattened epithelium, filled with stainable colloid. Normal.
2015 B. Closely packed follicles of irregular shape with almost complete absence of colloid. Follicles lined with cubical
epithelium. Small groups of detached follicles lying outside the closely packed area lined with flattened epithelium and filled
with stainable colloid. First evidences of hyperplasia. Beginning simple hyperplasia.
2015 C. Between the second and third gill arches the space is filled with loosely arranged follicles, many of which contain
stainable colloid and are lined with slightly cubical epithelium. Between the follicles, marked hyperemia and engorgement of
the vessels. Away from this mass in this area of slightly altered thyroid one finds isolated typical normal follicles with deeply
staining colloid and flattened epithelium. Again, about the aorta above and below it, one finds one or two aggregates of follicles
with slightly cubical epithelium and evidences of hyperemia. The remainder of the thyroid tissue about the large vessels strictly
normal. Hyperemia of the thyroid, possibly beginning hyperplasia. Unusual amount of thyroid tissue.
2098 A. Tumor. Typical alveolo-solid carcinoma for the most part, with areas of papillary formation. Infiltration of muscle,
bone, and cartilage. Infiltration of wall of vein. Papillary adenoi-carcinoma infiltrating muscle bone and cartilage. Hyaline
degeneration of the wall of the media of the aorta. (Fig. 90.) ^
2098 B. Beginning adeno-carcinoma of tubulo-alveolar type. Infiltration of areolar tissue, dense connective tissue structures,
periosteum of bone and muscle.
2099 A. Examination of this section shows an unusual amount of thyroid tissue about the large vessels, small follicles lined
with flattened epithelium, some of them containing stainable colloid, others poorly stained colloid, many of them empty, pushed
in flattened strands between the dense connective tissue structures, spreading well forward into the areolar tissue and in the
adjacent bone cavities. (Fig. 91.) Great increase in the amount of thyroid tissue. Only one or two large follicles filled with
stainable colloid. Immediately adjacent to the large vessels a few follicles with high cubical epithelium and no colloid. The
Whole specimen indicates the previous existence of well-developed hyperplasia followed by regression.
2099 B, C. Presents the same histological characteristics. Increased amount of thyroid tissue. Many isolated groups
widely distant from the large vessels. About the large vessels are many tortuous elongated and branching alveoli of tubular
type, lined with flattened epithelium, free from colloid. (Fig. 92, under "Spontaneous Recovery.") Colloid almost entirely
absent.
CARCINOMA OP THE THYROID IN SALMONOID FISHES. 463
2101 A. Small closely-packed follicles lined with flattened and low cubical epithelium. No colloid. Marked increase in
amount of thyroid tissue. Many follicles and flat strands of follicles between the muscle bundles in the areolar tissue, floor of
the mouth, and bone cavities. Regression from well-developed hyperplasia.
2103 A. About the large vessels are individual follicles lined with columnar epithelium, filled with faintly staining colloid.
These follicles are irregular in shape. Slight infoldings of the vesicular wall with beginning bud formation. Protoplasm of the
cells stains deeply. The nuclei are vesicular, of great variety of size. The long axes of the nuclei are perpendicular to the cir-
cumference. Marked hyperemia of the small vessels between these follicles. In the same field by low power may be seen
individual follicles of typical normal appearance, flattened epithelium filled with deeply stainable colloid. We have here
beginning focal hyperplasia. Certain groups of follicles are lined with flattened epithelium, contain no colloid, are elongate,
branching or irregular in shape, and present an appearance suggesting regression of individual follicles.
2104 A, B. Marked increase of thyroid. Follicles closely packed and spherical, some filled with stainable colloid. Some
follicles of irregular shape or branching. Widely scattered follicles in the areolar tissue and between the fibers of the dense
connective tissue structures. Regression of hyperplasia.
mi A. Spherical and oval follicles filled with stainable colloid and lined with flattened epithelium. Engorgement of the
vessels between the follicles. Slight hyperemia. Normal.
CHEMOTHERAPY.-1
THE EFFECT OF IODINE. MERCURY. AND ARSENIC UPON CARCINOMA OF THE THYROID.
The knowledge of the occasional effect of iodine as a remedy in goiter is almost as
old as our knowledge of the disease itself. The relation of iodine to the thyroid has
been the subject of extensive study by modern chemical methods and by biological
experiment. It is well known that the thyroid gland normally contains iodine, and it
has been contended that in certain hyperplasias of the thyroid the amount of iodine
per gram weight of thyroid tissue is reduced. These facts have led experimenters to
hold that the curative effects of iodine upon the hyperplastic thyroid is more due to a
restoration of the iodine content to a normal basis than to the specific action of iodine
administered as a remedy. In the mammalian hyperplastic thyroid there are fre-
quently encountered small adenomata which are more or less distinct in appearance from
« Themeasures to be taken by fish culturists for the prevention of thyroid carcinoma must await a careful investigation planned
specifically with this end in view. This we have not been able to undertake. We believe, however, our experiments with
wild fish point the way along which efforts should be directed.
The matter of food is undoubtedly the most important aspect of domestication in relation to thyroid disease. The livers of
cattle, sheep, and hogs are chiefly relied upon in rearing the salmonoids, and the extent to which this food is varied or replaced
by heart, lungs, horse flesh, and other animal proteids apparently does not alter the situation in this respect. Their availability
as fish food makes it difficult to displace them, but fortunately they are not inherently necessary to fish culture. Vegetable food
made from staple grains, fresh-water and marine fish and mussels, Entomostraca and other Crustacea, live maggots and even
living adult insects, have been used more or less as foods in practical fish culture. Most of these are not yet available in quan-
tity, and none has displaced entirely the mammalian proteids. Our feeding experiments, however, indicate that such foods
would maintain normal thyroid glands in the sahnonoid fishes. To devise and prove a composite ration properly balanced for
this purpose would seem a fish cultural problem worth while. Perhaps a cooked mixture consisting largely of vegetable
meal in which was incorporated fish flesh and a minor portion of one of the foods used commonly at present would promise
best. Possibly even small quantities of insects and insect larvae added to this would be an important improvement. Such a
food has ever been a prime desideratum in fish culture and affords a measure of protection against most fish diseases as well as
against the one now under discussion.
Holding the disease to be an infection, the ultimate problem is largely one of prevention, under which would come a more
stringent cleanliness of fish troughs and ponds, possibly the annual painting of wooden containers and in the case of dirt ponds,
their occasional emptying with periods of sun-drying, or a change to cement construction. The selection and breeding of resistant
strains, or of resistant species like the Scotch sea trout, are obviously indicated.
As for the presumption, which experiments indicate, of remedial possibilities in the use of mercury or iodine, there is no
sufficient basis at present for recommending their use on a practical scale. This would involve their administration over consid-
erable periods of time which their cumulative action might render undesirable. Moreover, that they are absolute preventives
of the disease process under discussion is not yet demonstrated. The control of this disease can doubtless be brought about by
other means than administration of chemical agents. To this end a fish-cultural station handling preferably the brook trout
could well be devoted to the extended experiments having to do with feeding and the access of infection to the fish which are
necessary both to more exact knowledge of the disease and to its practical relations.
464 BULLETIN OF THE BUREAU OF FISHERIES.
the surrounding hyperplastic tissue and have been looked upon as developing from
embryonic rests, especially rests of. the original tubular structure of the fetal gland.
From these adenomata the malignant neoplasms of the thyroid are supposed to take
their origin.
Marine and Lenhart (igiob, p. 20; 191 la, p. 22), who have extensively studied the
effect of iodine upon the mammalian thyroid, have advanced the theory that hyperplasias
of the thyroid including endemic goiter are due to insufficiency of iodine in the diet of
the individuals and that the therapeutic effects of iodine are the result of restoring to
the thyroid the normal amount of iodine. They state that nodular struma or the ade-
nomas found in strumous thyroids are unaffected by iodine, and that malignant tumors are
unaffected by iodine, and they propose that the administration of iodine shall constitute
a biological test for the purpose of distinguishing between hyperplasias which they hold
to be due to a physiological deficiency of iodine and malignant tumors which they state
can not be affected in this way. The evidence of the microscope is no longer to be con-
sidered; the final test is to be whether or not a given enlargement of the thyroid responds
to iodine. It is obvious that such a test as Marine and Lenhart have proposed is not
applicable to malignant tumors other than the thyroid, as it has long been known in
experimental cancer research that transplantable mouse cancer is definitely influenced
in its growth by many chemical compounds (Clowes, 1908), particularly the heavy
metals.
Schoene (1910) showed that for a time regression of advanced implanted mouse
cancer could be induced by the intraperitoneal injection of iodine and mercury in the
form of KI and HgCl2. He found the effect of mercury to be much more marked than
that of iodine. It was thus known that iodine had an inhibitory effect upon genuine
neoplasms and it therefore seemed possible that the action of iodine upon the proliferating
thyroid might be due to some specific action upon the tissue, such as these experiments
of Schoene's indicated the agent possessed for genuine neoplasms of other organs.
Marine and Lenhart reported in 1910 that fish suffering with hyperplasia of the thyroid
were favorably affected by adding iodine in the form of Lugol's solution to the water
in the troughs in which they were kept, and from these observations applying the theory
above stated, concluded that the so-called carcinoma of the thyroid in the Salmonidae
was not carcinoma but simple hyperplasia, distinguishable from true neoplasms by the
favorable effect of iodine upon the tissue. The remarkable infiltrative character of these
neoplasms, so well described by Scott, Plehn, and Pick, and reported in our first prelim-
inary reports, Marine explains as due to the absence of a capsule. This feature of
the case we have dealt with under the appropriate heading and it need not be again
referred to here.
The results of Marine and Lenhart in causing regression or, as they term it,
involution or reversion, of the hyperplastic thyroid in the Salmonidae by the administra-
tion of iodine through the water, we have been able to confirm. In order to determine
whether the action of the iodine was peculiar to this element and might therefore be
looked upon as acting upon the thyroid by virtue of its physiological relation to this
organ, in repeating the experiments of Marine and Lenhart we decided to control them
CARCINOMA OP THE THYROID IN SALMONOID FISHES.
465
by treating under exactly the same conditions comparable fish with mercury in the
form of HgCl2. This gave the further advantage that if mercury should prove to have
a similar effect upon the thyroid to that determined by Marine and Lenhart for iodine,
the relation of these growths of the thyroid to one of the heavy metals might be deter-
mined, mercury already having been shown to have an inhibitory and regressive effect
upon genuine neoplasms. The experiments were carried out in the summer of 1910
with the result, as may be seen by the accompanying tables, that mercury was found
to have an effect upon the growing thyroid of the Salmonidae indistinguishable from
that obtained with iodine, with the exception that mercury appeared to produce these
results more certainly and more rapidly than did iodine. To further amplify the
FIG. 95.— Floating siphon. A is the siphon, B the frame, and C the container. The form of the frame is of course not
essential, and should be adapted to the container. The illustrations show the glass tubing of much larger size than is neces-
sary or practicable in small siphons. Small tubing is preferable.
comparison, during the summer of 1911 experiments with arsenic, an element long
known to have a favorable influence upon genuine neoplasms, were carried out, using
arsenic in the form of As3O5. These results are also sufficiently set forth in the tables.
Experiments were begun by determining the toxicity of the iodine to trout when
added to the water in the form of the pure element already dissolved in distilled water
and then added to the dissolved potassium salt. The uncombined iodine is much more
toxic than the potassium iodide. Lake trout fry were killed in less than 20 hours by
one part of free iodine added to 400,000 parts of tap water. Dilutions of i to i ,000,000
are safe, perhaps because the iodine is combined before it has time to produce a fatal
466 BULLETIN OF THE BUREAU OP FISHERIES.
result. At i to 600,000 brook trout yearlings were not killed during three days, but
the effect of iodine was seen in coagulating the slime on the bodies of the fish.
In the form of potassium iodide, i part of iodine in 25,000 parts of tap water killed
brook trout fry in two to six hours, but i to 50,000 was harmless during a trial of two
weeks. Lake trout fry were uninjured by dilutions of i to 200,000 and weaker.
The administration of the chemical agents has been accomplished in several different
ways and in various dilutions. The constant uniform dilutions were maintained by
running a solution of known strength continuously into the fish troughs with the
measured water inflow at the head of the trough, an intimate mixture being insured.
A barrel was used as a receptacle for the solution and a constant head for the flow of
solution was maintained by the use of a floating siphon. (Fig. 95.) In this way it
is easy to keep the water supply of the experiment constantly impregnated to any
desired degree with any soluble agent.
The intermittent treatments were applied by adding single doses of the chemical
to the water of the fish trough, obtaining fairly complete distribution by stirring. Two
daily doses were given, and the water supply was so adjusted as to change the contents
of the trough every four-hour period. The dilution of the chemical then proceeded with
the flushing out of the trough by the water flow. The corners of the trough may have
still held appreciable quantities of the agent after the four-hour period, but the flow
must have diluted it beyond any effective strength long before the succeeding portion
was added.
Experiment i (table ix). — Iodine administered as potassium iodide and given con-
tinuously under constant head from a floating siphon into a trough receiving an ade-
quate and measured water supply direct from Craig Brook and having a definitely
known outflow. The water supply was 24 liters per minute. The siphon flow of KI
solution was so regulated that a constant concentration of iodine of i : 5,000,000 was
maintained in the flowing water. The temperature of the water during the course of
the experiment varied but little from 19.5° C. The fish were fed raw beef liver. The
following fish were subjected to this treatment : Three tumored hybrid salmon, 6 tumored
brook trout, and 15 clinically clean brook trout. An equal number of controls living
under identical conditions, with the exception of the presence of iodine, were carried
through for comparative study. The greatest period during which fish were subjected
to this treatment was 31 days. Treated fish and controls were preserved for study,
however, at frequent intervals during the course of the experiment. A brief statement
of results is given in table ix. This is self-explanatory. (Fig. 96, 97, 98, 99, 100, 101.)
Experiment 2 (table x). — Similar in all respects to experiment i, except for the
concentration of iodine, which was much greater, being i : 300,000. The fish were fed
raw beef liver. The fish subjected to the treatment were as follows: Four clinically
clean brook trout, 5 brook trout with pharyngeal discoloration (red floor), and 6 brook
trout with various tumors. Parallel controls for all these fish were also studied. The
longest period of treatment in this experiment was 17 days. Macroscopic evidence of
regression was furnished in some of the red floors and in some of the tumor fish as
shown by the disappearance of pharyngeal reddening and reduction of tumor measure-
ment. The results of microscopic study of these specimens, together with their controls,
are given in table x.
Experiment j (table xi). — In this experiment iodine was administered intermit-
tently as potassium iodide, the greatest concentration of iodine in the water at any one
CARCINOMA OF THE THYROID IN SALMONOID FISHES. 467
time being i : 32,000,000 parts. From this strength dilution rapidly occurred, reaching
infinity in about four hours, the time required for the replacement of the water contents
of the trough containing the fish experimented upon. The iodine was administered
twice daily, morning and evening, so that there were long periods during which the fish
received no iodine. The temperature of the water remained quite constant at 19.5° C.
These fish were fed raw beef liver. The longest period of administration was 30 days.
The fish employed were 15 clinically clean brook trout yearlings and 5 small tumor
brook trout yearlings. No special controls were employed for this experiment, com-
parisons being made with the controls for the previous iodine experiment. Here again
some macroscopic evidence of regression was furnished by diminution in size of tumors.
A brief resume of the microscopic study is given in table xi.
Experiment 4. — A small number of fish were tested for the toxicity of iodine admin-
istered as Lugol's solution into the stomach, and it was found that yearling trout will
endure as much as i to 5 mg. and adult trout as much as 10 mg. A number of fish were
treated, some of them during a period of 21 days, with injections into the stomach of
Lugol's solution containing from 1.16 mg. to 3.75 mg. iodine. Some of these died,
probably through the cumulative effect of the iodine. Definite reduction of tumors
was observed. Microscopic evidence of regression, although in the main not as marked
as that occurring in other methods of treatment, is nevertheless definite.
Experiment 5, showing the influence of mercury (table xn). This experiment is
comparable with experiment i showing the effect of iodine administration. Mercury
was administered as HgCl2, under constant flow, in a dilution of i : 5,000,000 of mercury.
The following fish were subjected to this treatment : Fifteen clinically clean yearling
brook trout, 5 brook trout showing red floors, and 3 brook trout with tumors. Parallel
controls receiving no mercury were employed. Fish were killed and preserved at fre-
quent intervals, the longest duration of treatment being 30 days. The experiment was
begun August 13, 1910. The temperature of the water was 20° C. ; feeding, the same
as for other experiments. Here, also, macroscopic evidence of regression was furnished
by clearing up of red floors and diminution in size of tumors, and in the almost complete
clinical disappearance of a tumor 7^ rnm. in diameter. A brief summary of the results
of microscopic study is given in table xn. (Fig. 102, 103, 104, 105, 107, 108.) Three
days is insufficient to affect tumors. In one case, however, after three days in
i : 5,000,000 the fish was placed in i : 300,000 and was killed by the mercury in three
and one-half hours. The epithelium showed great reduction. (Fig. 106.) Another
after three days in i : 5,000,000 and 2.75 mg. of HgCl2 introduced into the stomach on
the second day showed no reduction.
Experiment 6 (table xm). — Intermittent administration of mercury as HgCl2;
camparable to experiment 3 (intermittent administration of iodine). Mercuric chlo-
ride was introduced into the water of the trough containing the fish experimented upon
in such quantity as to make a solution, for the moment, representing i part of mercury
in 38,600,000 parts of water. This was done twice daily, at 10 a. m. and 4 p. m. The
dilution was estimated to have reached infinity in four hours. Five tumored brook
trout and 10 clinically clean landlocked salmon were subjected to this treatment for
periods of 15, 31, and 43 days.
With this high dilution of mercury, even at the end of 43 days there was no definite
macroscopic evidence of reduction in size of any of the tumors. The histologic study of
the 15 fish of this experiment, together with i tumor and i clinically clean control,
appear briefly summarized in table xm. Of the 15 fish subjected to treatment, 5
show distinct evidence of regression, either in thyroid hyperplasia or tumor; 2 show
slight regression; 2 are doubtful; and 3 show no evidence of change.
468 BULLETIN OP THE BUREAU OF FISHERIES.
The results, therefore, from mercury in such high dilution and given intermittently,
are less marked than with the high iodine dilutions and the less dilute mercury and
arsenic. Nevertheless, as compared with controls, even given in these extremely small
quantities, there is an undoubted effect from the mercury.
Experiment 7 (table xiv) .—Arsenic administered in continuous flow, as As2O5,
delivered constantly, drop by drop from floating siphon, making a dilution equivalent
to i part of arsenic in 300,000 parts of water.
Five clinically clean landlocked salmon and five tumored trout were subjected to
this treatment. On the fourteenth day of the experiment the following fish were killed
and preserved for microscopic examination: One with throat tumor, one with a throat
and mouth tumor, and two clinically clean. In addition, two controls, one tumored
and one clinically clean, were preserved for comparison.
At the end of the twenty-second day the experiment was discontinued and the
remaining fish preserved. These consisted of three originally clean landlocked salmon
and three originally tumored brook trout. Of the latter, there was only one visible
tumor left and that greatly reduced in size. In another a red floor was the only visible
sign of what was originally a fair sized tumor. (Fig. 109.) In a third there was no
macroscopic evidence of the former tumor.
Microscopically all the thyroids of the fish subjected to treatment showed distinct
evidence of regression. This was most marked in the fish in which treatment had been
continued for 22 days. The controls, on the other hand, had undergone no regression.
The results of microscopic study are briefly outlined in table xiv.
During the winter of 1910, in order to determine whether the results obtained by the
administration of thymol in endemic goiter by McCarrison could be duplicated by the
administration of this drug through the medium of the water upon fish with carcinoma
of the thyroid, the following experiments were carried out: Thymol at i part to 500,000
of water, dissolved by the aid of heat maintained constantly in flowing water for 34
days, was without recognizable effect macroscopically or microscopically upon either
visible tumors or the early stage. The temperature of the water ranged from 2° to 3° C.
A brook trout yearling was killed between the second and third day by thymol at i to
200,000, indicating that solution of the thymol in the water was attained.
Generally speaking, iodine, mercury, and arsenic produce changes in the prolifer-
ating thyroid tissue, both in the early and advanced stages of carcinoma of the thyroid,
which are scarcely distinguishable from the changes found in spontaneous recovery.
In the early stages the change consists in a reversion of the columnar epithelium to the
flattened form, return of stainable colloid, disappearance of hyperemia, and the partial
disappearance of the most remote extensions of follicles in the outlying tissues. Where
regression occurs rapidly in large tumors the first evidences of regression are found in
extensive hemorrhages into the substance of the tumor; in some instances extensive
areas of the tumor are the seat of hemorrhage. Such hemorrhages are organized by
connective tissue. (See fig. 101.) The high columnar epithelium, especially in the
peripheral portions of the tumor, are changed to flattened and atrophic cells with
greatly diminished protoplasm. The retrograde changes are most marked at the periph-
ery, and the entire picture is like that described under spontaneous recovery, except
that the process seems to be more rapid and more extensive under treatment with
metals. The effect of the metals, particularly mercury, is found as soon as the eighth
CARCINOMA OF THE THYROID IN SALMONOID FISHES. 469
day, and in one instance where a fish with a large tumor (fish 1136 of table xn, fig. 108)
was subjected to mercury by immersion for three and one-half hours in water containing
a much higher concentration than usual, by which it was apparently poisoned and
promptly died, the changes in the tumor were comparable to results obtained only
by an exhibition of mercury at i : 5,000,000 during a period of not less than 20 days.
Since the experiments above referred to were completed, our knowledge of the action
of the heavy metals upon carcinoma in experimental animals has been amplified by the
experiments of von Wassermann, who has shown that the intravenous injection of
selenium in combination with eosin, when given in large doses, is capable of causing the
complete regression of large implanted mouse cancers, followed by clinical cure. In
considering the results obtained by ourselves in carcinoma of the thyroid in the Sal-
monidae, showing the pronounced effect of iodine, arsenic, and mercury, it became
evident to us, after the publication of von Wassermann's results obtained with selenium,
that it was highly probable that suitable compounds of any of the heavy metals would
prove to have a more or less distinctive effect upon neoplasms. That this is the case
is now shown by the publication of Neuberg, Caspari, and Lohe (1912) and the results
obtained by the use of colloidal metals by Szecsi (1912), and the favorable, although
temporary results obtained by the French observers in the use of colloidal copper in
human carcinoma.
All of these experiments, as did the original observations of Schoene, dealt with
large doses, in many instances almost a fatal dose of these metallic compounds given
intravenously. Lewin (1913) has recently pointed out that where immediate results
are obtained with metals, there is evidence of marked hemorrhage into the tumor, and
believes that they are able to affect the tumor by their ability to injure the capillary
terminals, this explaining the hemorrhage. Although in our experiments arsenic and
mercury were used in very great dilution, we have the same evidence of hemorrhage
into the tumors, especially the large ones that are obtained by injecting much larger
doses intravenously in animals. It seems highly probable that the results obtained
with this great dilution are due to a cumulative action of the metal. It is, however,
clear that the results obtained in our experiments are of the same nature as those
obtained in neoplasms of experimental animals by intravenous injection. (Gaylord,
1912 a.)
It seems assured that the action of iodine upon the tumors of the thyroid in the
Salmonidae is not due to its physiological relation to the thyroid gland; that its curative
qualities are equally possessed by other elements, including the heavy metals, and that
it acts by virtue of some quality which it shares in common with the metals; that these
metals exhibit the same effect upon true neoplasms in mammals and that the effect of
iodine and metals upon the tumors of the thyroid in the Salmonidae tends to prove their
true neoplastic nature, and that the theory of Marine and Lenhart that the action of
iodine may be used to distinguish between physiological hyperplasia and true tumor
formation is untenable.
470
BULLETIN OF THE BUREAU OF FISHERIES.
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Epithelium.
High, throughout cu-
boidal to columnar.
Some columnar; some
high cuboidal; some
low cuboidal; some
cubical and flat-
tened; mostly mod-
erately high.
Mostly low, cuboidal
in type, cubical, and
in some follicles flat-
tened.
Many follicles lined by
low cuboidal, many
by high, no colum-
nar, mostly high.
Mostly low; many flat-
tened, a few lined by
low columnar.
Mostly high cuboidal
to columnar, mark-
edly higher than hi
8-day Hg. fish.
Low, cuboidal to flat-
tened.
High; many follicles
with high columnar.
ill
Moderately high
Low, cuboidal to com-
plete reduction.
8
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BULLETIN OF THE BUREAU OF FISHERIES.
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CARCINOMA OF THE THYROID IN SALMONOID FISHES.
479
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e c i d e d regression .
20558; card 1126.
oderate hyperplasia.
20558; card 1129.
ery positive regression
20558; card 1128.
istinct regressioii .
20558; card 1130.
oderately advanced h
plasia; controls for n<
Lot 20558 ; cards 1134^
H34B.
e c i d e d regression .
20558; cards 1133 A
"33B.
oderately advanced h
plasia. Lot 20558;
1132.
arked regression.
20558; card 1131.
Iso received 2.75 mg. 1
in stomach one day h
death; no microscopu
dence of reduction.
"35-
days hi Hg i to 5,00
then in standhlg Hg
300,000; killed by sJ4 1
exposure; striking r
tion. Card 1136; fig.
Iso 2.75 mg. HgCl
stomach 2 days t
death- no apparent r
tion. Card 1137.
eginning reduction
marked histologically
none evident micro
ically. Card 1138.
isthict reduction ma
in some parts of tu
none hi others. Cards
and 1140.
arked reduction; sam
as no. 27. Card 1141.
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High; cubical
lumnar.
Low, cuboidal 1
plete reductic
Low, cuboidal.
High, some coli
Low; very Ic
boidal to co
reduction.
High, cuboidal
lumnar.
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High, mostly
columnar.
Low; high in
few follicles.
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Mostly high;
shows reduct
Variable; hi tl
loid filled f
low, hi other
Uniformly low
erately high i
a few follicles
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Much less thyroid, more widely separated,
larger follicles.
Fairly large thyroid mass of varying folli
soine very closely packed; others wi
separated.
Much less thyroid, more uniform; larger
widely separated follicles.
J
9
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Large number of good-sized follicles, s
loosely arranged, others compact; very 1
infiltration of muscle.
Smaller number of larger follicles more loc
arranged.
Large number of follicles, varying in size
shape, infiltrating muscle.
Thyroid much smaller; more uniformly 1
follicles.
Tumors; pit and throat reduced i mm
diameter; much papilliform epithelial
vagination.
A large number of large follicles, more com
near pharyngeal floor.
Large mass closely packed follicles, n
epithelial invagination; infiltration, mi
and cartilage.
Tumor reduced from 14 mm. to 18 nur
diameter, very cystic; large cysts
rounded by compact thyroid contai
many small follicles.
Tumor reduced hi size; large follicles, n
irregular and with branching epithelia
growths around these; more compact sm
follicles, others more scattered; foil
smaller.
Microscopic evidence of reduction; extrei
large follicles, surrounded by layer of sm
ones; some have ingrowing epithehal pi
he.
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480
BULLETIN OF THE BUREAU OF FISHERIES.
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Epithelium.
igh, mostly cu-
boidal, some colum-
nar; many follicles
at periphery of tu-
mor mass have re-
duced epithelium.
uch low epithelium,
considerable desqua-
mation; probably
postmortem changes.
ery low ; mostly com-
plete reduction, a
few cuboidal.
ery low
ostly low, cuboidal;
a few high, some co-
lumnar.
ostly very low; a few
follicles high to low
cuboidal.
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ndition of thyroi
oi
amount
connective tis-
some smooth
cle, some hemor-
e.
lerable connec-
tissue and loose
lar.
loose areolar,
t connective tis-
connective tis-
loose areolar;
orrhages, leuco-
:infiltrationand
-like spaces.
connective tis-
especially at pe-
ery.
8
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Distribution. Infiltration.
mor reduced in size; many large ii
)llicles, some with papilliform ingro1
roat tumor which has become s
losely packed follicles and some ep
lasses; invasion of muscle and cartil
mor reduced ^4 mm.; numerous,
x>sely packed, large follicles, mucl
ing out at periphery of mass, large
les in center of mass; no evident i
ion.
merous large follicles loosely packec
ery large like colloid cysts.
mor little if any reduced in size; gri
losely packed follicles separated b
reolar and connective tissue.
mm. tumor nearly gone, consistsin
irge and small follicles loosely an
thers more compact; tumor much t
ut at periphery; small atrophied foil
3 **5
43 <J H
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CARCINOMA OP THE THYROID IN SAL/MONOID FISHES.
gi i A-O
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la 2*° ;?
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, sahnon, clinically da
no marked evidence of
gression; moderate hyp
plasia, if anything ret
gression. Lot 1950; ca
2O2OA.
. sahnon, clinically cles
retrogradulg hyperplas
Lot 1950; card 20208.
rook trout; large thr(
tumor; no regression; 1
histologic appearance
malignancy. Lot aa
card 202 1 A.
. sahnon; clinically cles
control for no. 2; apparc
regression of moderate 1
perplasia. Lot 1950; ca
2022.
rook trout; pit turn
some regression; adenon
mixed tumor. Lot 22
card 2023.
rook trout; tumor, mot
and pit, in microsco]
evidence of duninutk
apparent regression. I
2215; card 20218.
. sahnon, clinically cle;
very moderate hyperp
sia; apparently distind
retrograding. Lot 19
card 2O26A.
. salmon, clinically cl«
moderate hyperplasia;
trograding. Lot 1950; ca
20268.
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Pharyngeal spaces filled -with loosely packed
follicles of varying size, some very Jarge and
some very small, very few of irregular out-
line; some invasion of muscle.
Isolated masses of mostly small follicles sepa-
rated from each other by large hemorrhagic
areas; thinning out of follicles under pharyn-
geal floor; some large follicles and a few small
colloid cysts; some invasion of muscle and
cartilage.
Pharyngeal spaces completely filled with sol-
idly packed columns and masses of epithe-
lium with only an occasional distinct alve-
olus in some parts and scattered alveoli in
others, widely separated by packed epithe-
lium; invasion of muscle and bone.
Pharyngeal spaces partly filled with typical
alveoli, but varying greatly in size; no in-
vasion of cartilage bone or muscle; occa-
sional small cyst.
Mixed tumor, in part closely packed epithelial
cords; in part adenoma tous large papilhform
ingrowths near surface; scattered colloid con-
taining alveoh.
Pharyngeal spaces filled with spherical follicles,
part of which are small and closely packed and
part large; many very large and filled with
colloid.
Relatively small masses of loosely packed fol-
licles, well separated, of varying size, spher-
ical in outline.
Pharyngeal spaces moderately filled with
closely packed follicles, some of which are
very small.
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BULLETIN OP THE BUREAU OF FISHERIES.
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CARCINOMA OF THE THYROID IN SALMONOID PISHES.
483
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Distribution. Infiltration.
Pharyngeal spaces partly filled by follicles of
varying size and shape, some compact,
others loosely arranged, many separating
spaces of areolar tissue; apparent disappear-
ance of follicles under pharyngeal floor; some
invasion of cartilage.
Layer under pharyngeal floor; flattened out
follicles between fibrous tissue, which has
largely replaced the thyroid at this point; the
visible tumor portion is also almost entirely
replaced by connective tissue; the center
growth papilliform in type, separated from
surrounding tissue by dense fibrous tissue
which has apparently replaced former
thyroid.
Pharyngeal spaces filled with a very variable
thyroid mass, containing islands of papilli-
form follicles surrounded by typical follicles
and masses of new formed connective tissue
embedding compressed follicles; periphery
of tumor largely replaced by connective
tissue; infiltration of muscle and cartilage.
Pharyngeal spaces partly filled by a variable
thyroid mass; some follicles small and closely
packed ; others large, separated by strands of
muscle; no invasion of cartilage; not involv-
ing floor.
Rather widely separated and loosely arranged
small and large follicles scattered through
pharyngeal spaces.
Islands of papilHform growths walled off by
large masses of new formed connective tissue
with scattered follicles.
Pharyngeal spaces only partly occupied by
thyroid follicles varying in ske and arrange-
ment from loosely to closely packed large
and small follicles.
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484
BULLETIN OF THE BUREAU OF FISHERIES.
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ontrol. Lot 2034?; th;
tumor, brook trout, gr
ing mixed tumor in i
adenomatous, in otl
goiter. Lot 2034; card 2
. salmon, clinically cl(
hyperplasia moderate,
definitely retrograd
Lot 2081; card 20348.
. sahnon, clinically cl«
moderate hyperplasia,
parently retrograd:
Lot 2081 ; card 2039.
rook trout; small throat
mor at beginning of tr
ment; tumor has entii
disappeared; marked
gression. Lot 2034; c
2040.
rook trout; originally i
dium-sized throat tun
at end of treatment bai
visible, much reduced
size; marked regressi
Lot 2034; card 2041.
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Distribution. Infiltration.
haryngeal spaces filled with thyroid m
divided partly by connective tissue into
eral masses of somewhat different charae
some ramifying papilliform, others large,
small follicles, invading bone and muscl
haryngeal spaces only partly filled by v
ing densely and loosely arranged small
large follicles; some invasion of cartilage
haryngeal spaces partly filled with mor
less closely packed follicles of varymg i
invasion of muscle; some follicles, ap
ently atrophic.
haryngeal spaces partly filled with mor
less loosely packed follicles, some small, i
ers large; apparent atrophy and thinning
in many places under pharyngeal floor; t
roid tissue has largely disappeared, isole
follicles only being included in a dense n
of new-formed connective tissue, part of
thyroid of the papilliform type shows cos
cence of follicles and a resumption of the t
cal colloid follicular arrangement.
:nter of mass papilliform, changing to col
containing follicles; at periphery large ;
small follicles separated by dense connee
tissue; invasion of muscle and cartilage.
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CARCINOMA OF THE THYROID IN SALMONOID FISHES. 485
TRANSMISSION OF THYROID DISEASE TO MAMMAUS.
DOGS.
In June, 1910, a dog obtained in Buffalo, and her litter of six young, were taken to
the Craig Brook station in Maine. They were placed in an inclosure near the fish ponds
and fed liver. They were immediately given to drink constantly water from pond 10,
and beginning with August 20 a pan of mud from the bottom of pond 10 with pond-io
water supernatant was supplied to them, the mud and water kept constantly renewed.
The animals not only drank the supernatant water but consumed the mud in quantity.
Seventeen days after the mud was first placed at their disposal all the puppies were
found to have palpable thyroid enlargements, besides greatly enlarged cervical lymph
nodes. This result was briefly reported at the Second International Cancer Congress at
Paris in 1910.
The food of the puppies was changed to cereal, and upon examination late in Novem-
ber, 1910, all the enlargements had markedly decreased. Two of the animals, dogs 14
and 15, were shipped to Buffalo in December and killed.
Section of the thyroid gland of dog 14, under the microscope presents an appear-
ance of the tissue easily discernible as normal. There is some variation in the size of the
follicles. The epithelium is flattened, the majority of the follicles filled with stainable
colloid. There are no evidences of hyperemia. Under high power the epithelium is
uniform in size, flattened, the protoplasm stains diffusely with hematoxylin, the nuclei
stain deeply, the long axes in the circumference of the lumen. There are no changes in
the stroma.
Section of the thyroid of dog 1 5 shows a remarkable condition of the tissue. There
is but the slightest suggestion of follicular structure in the section. (See fig. 113.)
The entire tissue is made up of solid masses of epithelial cells, with deeply staining
nuclei. There is absolutely no trace of colloid in any portion of the section. Com-
pared with dog 14 the epithelial cells and their nuclei are distinctly enlarged. The
nuclei stain deeply. They vary in size and at some portions of the section are vesicular.
The protoplasm stains diffusely with nuclear stain and is distinctly increased in amount.
Under high power the outlines of the follicles can be traced by capillaries. The entire
alveolar space is filled with irregularly shaped epithelial cells lying somewhat loosely
packed in some regions, more compactly in others. In the more open portions of the
section a condition suggesting papillary projections into the alveoli of the lumen may
be made out. The nuclei are vesicular. Occasional karyokinetic figures are found.
We have here intensive proliferation of the epithelium, with complete disappearance of
the colloid. Marked parenchymatous struma.
The remaining dogs of this lot were later shipped to Buffalo, and, at the last exam-
ination, made in July, 1911, no palpable thyroid enlargement was present. Thyroid
regression influenced by the change from a high animal protein to low vegetable protein
may be inferred.
A female brown spaniel (dog 24) obtained in Washington, D. C., was shipped to
the Craig Brook station in the fall of 1910. On November 30 there was no palpable
486 BULLETIN OF THE BUREAU OF FISHERIES.
thyroid enlargement. A bag of pond-io mud was now placed in a pail, which was
filled with Craig Brook water and placed in the kennel. The mud was not renewed,
but fresh water was poured over it from time to time. The dog was fed a meat diet.
July 5, 1911, the right thyroid (gland was found enlarged nearly to the size of a small
hen egg. The left gland was palpable but not evidently enlarged. During the next
year pond-io mud and water was supplied to the dog, and on July i, 1912, she was in
good condition, with both thyroid lobes decidedly enlarged. The left lobe was removed
and found to weigh 19.3 grams, its dimensions being 5.5 by 3.5 by 2.75-centimeters.
There was no control for this dog.
Under the microscope the thyroid of dog 24 presents follicles of great size filled
with stainable colloid, protruding into which are many bud-like processes. The epi-
thelium is columnar in the larger alveoli, the flattened nuclei stain deeply, are oval or
spherical, the protoplasm also taking the nuclear stain. The bud-like processes are
caused by infoldings of the walls of the alveoli covered with columnar epithelium. The
whole presents the appearance of a gland which has been in a state of active hyper-
plasia, but is at present a colloid gland.
The feeding of these dogs was intended as a preliminary informal trial and was not
controlled. Having indicated the probability of positive results in an important field,
more accurate experiments were begun with other young dogs.
A bitch with a litter of five pups was obtained from the District of Columbia, a
nongoitrous region. These were shipped to the Craig Brook station, in October, 1910.
The mother and two pups were supplied until the following summer with a pan of mud
from pond 10 holding pond-io water supernatant, both kept frequently renewed. The
three remaining pups were held as controls and received mud and water from Craig
Brook directly, unconnected with fish-cultural conditions. The food for all was shredded
wheat scrap and milk until December, when it was changed to dog biscuit with occasional
cooked liver, and this continued until spring, when it was again changed to cereal. The
two lots of dogs were separately confined in kennels indoors and were exercised and let
loose only under proper restrictions.
On palpation in July, 1911, no thyroid enlargement could be detected in any of
them. This experiment was now abandoned and a new one instituted with scrapings
from the inside of unpainted wooden fish troughs (no. 93), which had long been used to
hold domesticated trout and in which thyroid tumors were constantly produced in such
trout. (Table in.)
The three pups formerly used as controls were now given to drink Craig Brook water
from a pail containing the fish-trough scrapings suspended in a cheesecloth bag. The
material was kept cold by standing it continuously in a trough of flowing cold water.
A portion of the clear water from the pail was supplied to the dogs each day. The
mother and the two pups which had formerly received pond-io mud and water for several
months were now used as controls to the experiment with scrapings. They received
water taken from the same pail and boiled. All the dogs were fed liver, cooked and
uncooked. The experiment began August i, 1911, and in January, 1912, was terminated
CARCINOMA OP THE THYROID IN SALMONOID FISHES. 487
and the dogs shipped to Buffalo. The three which received unboiled water from the
scrapings were in poor condition and one of them died just before shipment.
Of these three puppies (dogs 16,17, and 22) the one which died spontaneously (dog 16)
and one of the others (dog 17), both had plainly palpable thyroids, from one-third to
one-half larger than normal, in gross section, firm and red, approaching spherical instead
of normal fusiform shape. In both instances the two lobes were about equally enlarged.
The section of the thyroid of dog 16 shows outspoken evidence of hyperplasia. There
are no spherical or oval follicles, all the open spaces in the tissue are of irregular shape
due to pronounced papillary projections of the epithelial structure into their lumina.
Colloid is present in some of the follicles. The greater area of the section is composed of
small irregularly shaped follicles many of which contain no colloid; others partly filled
with poorly stainable colloid. Under high power the epithelium is found to be high
columnar, the nuclei enlarged and often vesicular with one or more nucleoli. There is
distinct enlargement of the capillaries in the stroma. In many areas the proliferation
has been so intense as to practically fill the alveolar spaces with compact masses of
epithelium. Occasional deposits of brown hematogenous pigment are found within
the alveoli. There is distinct variability in the size of the nuclei, occasional ones being
greatly enlarged and vesicular. Karyokinetic figures are rare. Diagnosis: Marked
hyperplasia with great reduction of colloid. (Fig. in, dog 17.) The histological
description of dog 16 applies in every way to dog 17. (Fig. 112.) Diagnosis: Marked
hyperplasia with great reduction of colloid.
Puppy 22 was not operated until March 18, when the right thyroid was removed.
It was about normal in size, measuring 35 by 17 by 12 millimeters, and weighed 3 grams.
The dog weighed 7.71 kilograms. The third puppy (dog 22) presents a histological
condition in the thyroid similar to dogs 16 and 17. The epithelium is high columar,
the alveoli of irregular shape, due to plentiful papilliform processes into the lumen.
The larger alveoli contain poorly staining colloid. There is some variation in the differ-
ent portions of the section chosen for study in this case. One portion somewhat remote
from the more intensely hyperplastic region presents a somewhat more normal appear-
ance. The alveoli retain a more oval appearance, the papillary processes are smaller.
More colloid is present. The epithelium is, however, high columnar. The nuclei stain
poorly and more homogeneously than in the other regions where they are of a more
vesicular type. Diagnosis: Marked hyperplasia. (Fig. 115.)
None of the controls (mother and two pups, dogs 19, 20, and 21) had palpable
thyroid enlargements. They were all operated in March, and the left thyroid of each
removed. These left lobes were normal in size and appearance and similar in size to the
right lobes. The mother dog (19) weighed 10.9 kilograms, the left lobe 2.4 grams; one
of the pups (dog 21) weighed 8.6 kilograms, its left lobe 2.05 grams, measuring 32 by
17 by 9 millimeters. The other puppy (dog 20, fig. 114) weighed 10 kilograms; its left
lobe 6.4 grams, and measured 47 by 22 by 12 millimeters. Histological examination
of the thyroid of the mother (dog 19) shows normal thyroid structure for a dog of this
age. (Fig. 116.)
488 BULLETIN OF THE BUREAU OF FISHERIES.
The puppy (dog 21) presents a thyroid structure which may be considered normal
for a young dog. The alveoli are less spherical and oval, varying in size, filled with
stainable colloid. The epithelium is flattened. There are some areas in the thyroid
structure in which a slight tendency to budding of the epithelium with a change to
columnar may be observed and there are some areas in which there appears to be a
somewhat richer stroma than usual. It is, however, only an increase in amount of
connective tissue without any evidence of changes in staining characteristics of the
cells. As this puppy received pond-io mud and water for several months previous to
the final experiment, it is possible that the very slight changes here noted may be evi-
dence of the first beginnings of a change induced during that period. Diagnosis : Normal
thyroid of puppy. (Fig. no.)
Section of the left lobe of the thyroid of dog 20 shows follicles of varying size, the
oval and spherical type predominating, but some follicles in which there is evidence of
beginning bud formation. The lining epithelium of the more simple follicles is flat.
The follicles are filled with stainable colloid. In the somewhat more irregular follicles
the epithelium forming the budlike projections into the alveoli is cubical. The nuclei
are stained deeply and are spherical or oval. The details of the nuclei can not be made
out. Intensely stained. There is some slight thickening of the septa here and there
through the thyroid tissue. No evidence of hyperemia, no other change except the
slight budding. (Fig. 114.) The thyroid tissue is mostly normal for a young dog;
slight evidences indicating the beginning of hyperplasia. As this dog had previously
received pond-io mud and water, as had dog 21, slight evidences of hyperplasia may
be due to this previous stage of the experiment. Diagnosis: Areas of slight hyperplasia.
In the same way and beginning at the same time (Aug. i) as in the preceding exper-
iment, a young bull terrier (dog 18) was given to drink water in which was suspended
scrapings from another and old fish trough (no. 9 of old hatchery). The water,
however, was kept in the kennel and the dog allowed to drink at will. The tempera-
ture varied with the weather. In the winter the room was heated somewhat to prevent
freezing, but seldom rose above 45° F., and was often near the freezing point. The
control was dog 19, which received the scrapings water after boiling. Neither had
thyroid enlargement at the beginning of the experiment. The food was liver and dog
biscuit for both. The bull terrier, after receiving for six months water from the pail in
which were suspended the scrapings, showed a marked emaciation, muscular weakness,
and a staggering gait. The thyroid was readily palpable. The dog was killed and
both lobes found distinctly enlarged, the left lobe being about one-quarter larger than
the right and measuring 54 by 28 by 26 millimeters, and both very vascular.
Under the microscope the thyroid gland shows extensive pathological change.
The tissue is for the most part made up of a solid adenomatous structure with irregular
and narrow spaces representing preexisting vesicles. Under low power whole fields of
almost solid compact adenomatous tissue are found. In the irregular clefts and spaces
in the more open portions of the tissue, complex and marked papillary processes covered
with high columnar epithelium characterize the tissue. This change may be said to
be more constant in the peripheral portions of the section of the thyroid tissue. (Fig.
CARCINOMA OF THE THYROID IN SALMONOID FISHES. 489
1 1 8.) Passing toward the center of the lobe there are marked degenerative processes
in the tissue. The clefts become fewer in number, the epithelium stains less irregu-
larly than before, the irregular alveolar openings are fewer, and the whole tissue is com-
posed of a confusion of cells with just a suggestion of the previous clefts representing
the old alveoli (fig. 117), which in this region appear to be filled by desquamated and
rather poorly staining cells.
At the very center of the lobe the evidences of degeneration are more intense.
One finds masses of cell complexes, deeply staining and homogeneous protoplasm.
The cell boundaries are destroyed, the nuclei, although still staining deeply, are embedded
in the protoplasmic structure with only the most ill-defined suggestion of cell bounda-
ries to the protoplasm. (Fig. 119.) At the peripheral portion of the lobe where the
papillary adenomatous type of tissue is well preserved, no evidences of degenera-
tion are to be found. One finds in various places in the capsule evident invasion of
this structure. The capsule is thick, composed of fibrous connective tissue with small,
deeply stained connective tissue nuclei. In the dense fibrous structures of this capsule
at various points definite alveoli lined with high columnar epithelium are found, extend-
ing in some instances to the outermost limit of the thick capsule. Under high power
the epithelium of these alveoli and the capsule is found to be high columnar, most of
the nuclei staining deeply and homogeneously, but here and there are vesicular nuclei
with one or more nucleoli. The epithelium is in some of these alveoli several layers
thick; the protoplasm stains deeply with a cytoplasmic stain. Some of the larger nests
of cells in the capsule have almost lost their alveolar structure and formed more or less
compact islands of cells, with nuclei varying in size, many of them vesicular.
In the margins of such a complex of cells one finds direct invasion of the dense
connective tissue structure of the capsule, there being no stroma between the vesicles
and no delimiting membrane to them. In fact, individual cells can be found invading
the connective tissue fibers. Occasional karyokinetic figures are found and about the
larger masses of cells described there are evidences of expansive growth in the arrange-
ment of the immediate encircling fibers of the capsular structure.
Under high power the outer zone of adenomatous proliferation shows great varia-
bility in the nuclei of the cells, most of them being vesicular, with one or two nucleoli.
They vary in form from elongate to oval and spherical, mostly oval. The smaller nuclei
stain more homogeneously than the larger ones, the epithelium covering the papillary
projections is high columnar, the protoplasm stains diffusely, and occasional cells are
found in this region in which a swollen and cloudy appearance of the protoplasm indi-
cates the first evidence of degeneration. The stroma of the papillae is not well devel-
oped. The capillaries are plentiful but do not form a prominent part of the picture.
Approaching the center of the lobe, large irregular clefts, made up by the papillary
projections, are less in evidence and large areas are found in which the epithelium pre-
sents peculiar forms and a swollen, cloudy appearance of the protoplasm. The cells are
of the most bizarre form and shape, often are spindle shaped, and what has previously
been the alveolar spaces in the cells are filled with closely packed, desquamated epi-
thelium. The nuclei here still stain well, are vesicular in character, and vary greatly
8207°— 14 9
490 BULLETIN OF THE BUREAU OF FISHERIES.
in size and form. At the center of the lobule where the degenerative changes are most
outspoken are found large areas of desquamated cells with cloudy protoplasm, taking
the stain deeply. The cell boundaries are not sharply defined, the nuclei generally
smaller than in the preceding area, of varying size and deeply stained. Diagnosis:
Diffuse hyperplasia of the thyroid gland with degenerative changes at the center and
invasion of the capsule at the periphery.
RATS.
In 1910 and 1911 a prolonged attempt was made to affect the thyroid of rats by
giving them water to drink from the fish ponds in which the disease was endemic. A
barrel of water from pond 10 of the Craig Brook station and a quantity of mud from
the same pond were shipped to Buffalo and kept in cold storage. A series of experi-
ments were begun with young rats obtained from Granby, Mass. Each experimental
lot consisted of 10 rats. The food was a mixture of corn, oats, sunflower seeds, and
dog biscuit. The mud and water was administered daily to the separate lots as follows:
1. Trout-pond mud; small quantities.
2. Trout-pond mud; large quantities.
3. Trout-pond water.
4. Craig Brook water.
5. Trout-pond mud ; cooked.
6. Trout-pond water; boiled.
7. Trout-pond water, injected subcutaneously, followed by mud and water feeding.
The feeding of the mud, water, etc., was continued with the same individuals for
a period of about six months. A few were killed from time to time during this period
for examination of the thyroid. Neither in these nor in those remaining at the close of
the experiment were there any thyroid enlargements or any microscopic condition differ-
ing materially from the controls.
In the light of Bircher's subsequent observations there are several reasons why
these experiments might have failed. Bircher gives the following reasons why water
may lose its goiter-producing qualities : (a) Water kept under conditions different from
those of its origin for days or weeks; (6) water which before use has been continually
shaken or has undergone a long trip by rail; (c) water to which small amounts of chem-
ical agents have been added ; (d) that the agent is more active in the water in the sum-
mer months and that the source frequently loses its activity in the winter.^ Three of
these reasons bear on the possible negative nature of the above experiments, and as they
are all made with water taken from ponds in which the agent is present in dilute form,
it is quite clear that the length of time was not sufficiently great to produce positive
results. These experiments must therefore be repeated with the animals at the source of
water supply and continued over a period not less than 18 months.
The pond water and mud having failed to produce definite changes in rats during
six months under the experimental conditions, a quantity of scrapings from one of the
wooden fish troughs (no. 102), in which thyroid tumors were constantly developed, was
CARCINOMA OP THE THYROID IN SAI^MONOID FISHES. 491
brought to Buffalo. The material was kept cold in a thermos bottle during transporta-
tion, and on arrival was placed in a cheesecloth bag and immersed in a glass jar of water
and kept in the refrigerator. Preliminary trials were made by using this as drinking
water for rats on a raw-meat diet. No marked changes occurred during the first month,
but at four months one of six rats showed a great enlargement of the thyroid, and nearly
all had marked pathological changes consisting of reduction of colloid, increase in height
of epithelium, congestion and presence of numerous mitoses. A carefully controlled
experiment was now begun with the scrapings water, the diet being changed to dog bis-
cuit and salted lake herrings, the latter for the purpose of increasing thirst and con-
sumption of the water. Twenty-four rats received the scrapings water, and 12 control
rats received boiled water from the same source. This experiment is still in progress.
The results at the close of this record indicate that the rat thyroids undergo changes
similar to those in the dogs, but of a less intensive nature. Figure 120 shows a normal
thyroid of the rat from a control; figure 121, hypoplastic thyroid from a rat from this
experiment.
In considering the above experiments, from which it will be seen that a definite
enlargement with diffuse proliferation of the thyroid gland may be produced in dogs
in a period of five months by giving them to drink the water in which suspended scrap-
ings from wooden troughs in which the fish kept had regularly developed carcinoma of
the thyroid, and that the control dogs receiving the same water boiled have in the same
time developed no appreciable change in the thyroid gland, it naturally becomes impor-
tant to determine what is the exact character of the change in the thyroid gland of the
experimental dogs.
At the time, 1910, when the first experiments along these lines were made, we
were not aware of the experiments of Bircher and of Wilms in the production of
goiter in dogs and rats by giving them water to drink from goitrous wells. From the
various publications of E. Bircher it will be seen that in his results obtained in rats
(1911, b) he has produced, in periods varying from 9 to 18 months, distinct enlargement
of the thyroid, with pathological changes which he divides into two classes, viz, nodular
or adenomatous type and parenchymatous hyperplastic, mostly with degenerative
processes. In the nodular hyperplastic form he has produced typical struma nodosa,
which, as he points out, is a condition of the mammalian thyroid intimately associated
with tumor formation. The parenchymatous hyperplastic type seems to be an expres-
sion of a more intensive action of the goiter water, and it is to this type that the changes
we have produced in the thyroids of our experimental dogs more closely approximate.
In dog 1 8, in which we have the most outspoken change, we find distinctly marked degen-
erative changes of the protoplasm in the center of the lobe. These changes give, at
first glance, the impression of being due to poor fixation of the tissue or to post-mortem
change.
Changes of a similar nature have been produced by de Quervam (1904) in the thyroid
by the injections of toxic substances. De Quervain's studies indicate that the process
is intravital, and for his tumor rats Bircher takes the same position. It is of great
interest that Halsted, who originally (Welch, 1888) showed that by removing a part of
492 BULLETIN OF THE BUREAU OF FISHERIES.
the thyroid of normal dogs, the remaining portion would become hyperplastic (1896),
has recently (1913) repeated these experiments and now finds that when the present-day
aseptic methods are employed, especially the careful sterilization of the skin with iodine,
no compensatory hypertrophy results. Although not definitely expressing himself as to
the cause of the hyperplasia which followed his original experiments, in the light of de
Quervain's production of hyperplasia with the products of organisms, above referred to,
Halsted recognizes the possibility that the hyperplasia in the older experiments may
have been due to infection.
The experiments of Bircher indicate a very intimate relation between the experi-
mental production of struma in rats and dogs and the etiology of tumors of the thyroid.
The fact that he has produced nodular struma in rats, that struma nodosa is generally
looked upon as the change from wilich neoplasms of the thyroid in mammals spring, that
the other changes of the thyroid in his experimental rats present intensive parenchyma-
tous hyperplastic degeneration, makes it clear that perhaps the concentration of the
agent causing goiter and the method of its administration, the length of time in which
it is permitted to work, or the intensity of its action may determine the character of the
early changes of the thyroid in these experiments. The changes in our dogs have appar-
ently developed more quickly and more intensely than those in the experiments made by
Bircher. This would probably explain why our results have shown such diffuse and
intensive changes in the thyroids of our affected dogs. Dog 18, the only adult dog so far
exposed to the action of the agent in our experiments, presents outspoken degenerative
changes at the center of the gland and evidences of infiltration of the capsule. The
period of time covered by Bircher's experiments was much longer than those of our own.
We have reported briefly on a few experiments with rats, from which it is clear that
hyperplastic changes in the thyroid may be induced in rats under conditions similar
to those detailed in the experiments with the dogs. There are many other points of
similarity between Bircher's experiments and ours. The agent is in both cases destroyed
by boiling and it is not readily transported for a great distance. We have been unable
to produce changes in the thyroid of rats with water transported from Maine to the
institute in Buffalo. Our prompt and best results have, as with Bircher, been obtained
by giving the water from the scrapings freshly to the animals on the ground where the
agent is produced. We have not yet been able to carry out extensive filtration experi-
ments, but have such experiments in progress and hope to report on them later.
Bircher, in his experiments, has compared the results obtained in the production of
experimental struma in rats with the results obtained by de Quervain and argues there-
from that the agent of goiter as he finds it in Switzerland is probably a parasitic agent.
He finds in filtration experiments with moderately fine Berkefeld bougies that intensive
general degenerative changes of the nature of cretinism are produced by the residues
scraped from the outside of the filters, and infers that possibly it is the toxic products of
an organism which pass through the filter. These toxic products tend to produce struma
and the unfilterable portions possibly contain the organism that tends to produce
general constitutional disturbances of growth, i. e., cretinism. Our dog 18 showed
general nutritional disturbances, loss of weight and strength, staggering gait. To deter-
CARCINOMA OP THE THYROID IN SAI^MONOID 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 H. Bircher, jr., above referred to. Since his observations R£pin (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, Re"pin, 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 boiled 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.
494 BULLETIN OF THE BUREAU OF FISHERIES.
It would thus appear that water is not the exclusive carrier of the etiological agent
of goiter, but the giving of large quantities of water to experimental animals in a goi-
trous region, favors the development of goiter when the agent may find entry in some
other way. These observations tend to increase the significance of the finding of nema-
todes or other possible carriers in connection with the production of experimental
goiter in animals.
McCarrison (1909) produced experimental goiter in human beings by giving them
residues from the filtered water of Kashrote, where goiter prevails to the extent of
45 per cent of the total population. Experiments were carried out in the nongoitrous
village of Barmis so controlled that they were provided with water for drinking, bathing,
and other cleansing purposes from the Barmis spring, which is nongoiter producing,
but which, as an added precaution, was boiled. Their diet was chiefly vegetable. Of 13
individuals who consumed the untreated residue of the goiter-producing water of Kashrote
4 developed a noticeable swelling of the thyroid gland, while 2 others showed an increase
in size of the organ, demonstrable by measurement and evident to the touch. In three
cases the enlargement was produced early, making its appearance on the thirteenth to the
fourteenth day of the experiment. It was not great nor did it appear under the
conditions of the experiment to be progressive. Of eight individuals who under the
same conditions consumed the boiled residue of the goiter-producing water of Kashrote
none developed any swelling of the thyroid gland, and this although three were
individuals peculiarly likely to respond to goitrous influences. McCarrison therefore
concluded (i) that goiter is due to matter in suspension in the water; (2) that goiter
is not due to the mineral but to the living part of the suspended matter; in other words,
to a living organism of the disease; (3) that the incubation period of experimentally
produced goiter is 13 to 15 days.
An experiment of similar import is reported by Breitner (1912) which relates to a
family of father, mother, and seven children who, coming from a goiter-free region,
drank the water from a goitrous well with the result that all nine individuals developed
a great increase in the circumference of the neck with palpable tumors. Upon the
advice of Breitner they boiled the water from this source and after a period of four weeks
a distinct diminution of the thyroid tumors occurred, but later they disregarded this
advice with the result that the thyroid enlargement again progressed. From this well
Breitner carried out experiments with rats with the result that in 19 rats 2 developed
large visible struma, 2 thyroids two and one-half times as large as normal, arid 4 showed
microscopic diffuse enlargement of the thyroid, whereas 20 controls showed no
enlargement.
The literature contains many accounts of human beings going from nongoitrous
regions into localities in which goiter is endemic and there quickly acquiring the disease.
One of the oldest and most striking of those given is that reported by Hancke in 1819,
in which all but 70 young men of a battalion of 300 in the course of a year developed
such pronounced goiter that it was found necessary to remove the regiment to a non-
goitrous region, where those who were not too far advanced recovered, the enlargement
of the thyroid disappearing. Hancke states that in the infected region referred to
CARCINOMA OP THE THYROID IN SALMONOID FISHES. 495
individuals who boiled the water and freed it from the precipitate which it contained
and added thereto wine and sugar very rarely developed goiter. Another striking
example of the same kind is that of McClelland (1835) relative to an endemic of goiter
in Deoba, India. In this locality the entire population with the exception of the
Brahmins had goiter. This higher caste drew their drinking water from a widely distant
spring. One or two other castes which had partial access to this source numbered a
considerable percentage of goiter cases, and the lowest caste, the Domes, drew their
entire water supply from a goitrous well and almost every individual had goiter. The
middle caste, Ragpoots, which received partly good and partly infected water from the
well were infected to the extent of two-thirds of the individuals. These examples are
but one or two from many in the literature. Those who desire to multiply such reports
are referred to Hirsch's Handbuch der historisch-geographischen Pathologic (2. Stuttgart
1883, bd. 2, p. 83), and Ewald's excellent work on Die Erkrankungen der Schilddriise,
Myxodem und Kretinismus, in Nothnagel's Handbuch der speziellen Pathologie und
Therapie (2. aufl., Wien 1909, bd. 22).
It is clear both from recorded incidence in man and from experiments both
with man and animals that goiter is usually acquired through the drinking water. It
has been shown that from the water sources from which man acquires goiter, dogs and
rats may be made to develop it. We have shown that with water in which fish develop
carcinoma of the thyroid, diffuse parenchymatous enlargement of the thyroid in both
dogs and rats may be produced. From these facts inferences may be drawn that there
is every reason to believe that human beings also would acquire thyroid disease from
the use of such water.
POSSIBLE CARRIERS.
In a disease like carcinoma of the thyroid in the Salmonidae, which is not trans-
mitted directly from individual to individual but which is transmitted, if at all, from
the infected to the healthy by some roundabout method, the idea of carriers for the
agent which we believe to be the cause of the disease is very natural. Of the recent
experimenters with goiter water, Bircher, as a result of filtration experiments, for
some time advocated the view that the agent of goiter was a colloidal toxin, probably
liberated by some parasite incapable of passing the Berkefeld filter. The residues
scraped from such filters produced in young animals very profound nutritional changes
comparable to cretinism. The filterable factor which produces the nodular adenoma -
tous form of goiter, as well as the parenchymatous hyperplastic, will not pass through
the membrane of a dialyzer, but the residue upon the dialyzer membrane proved to be
particularly active. These observations have led Bircher to the belief that the agent
is a colloid, but he recognizes that it may also be a filterable microorganism; or that
if the organism itself does not pass the filter it is still the probable source of a filterable
toxin.
Many authors have held that endemic goiter is certainly an infectious disease,
Ewald being one of the strongest advocates of this theory, and McCarrison holds the
same view. Schittenhelm and Weichardt (1912) consider it an infectious disease and
496 BULLETIN OF THE BUREAU OF FISHERIES.
state that by immunizing rabbits with goiter water which was free from all bacteria
or other cultivable organisms, they have gotten with the blood of such immunized
rabbits a definite deviation of the complement reaction, as against the suppositions
organism in the water. By means of the epiphanin reaction they believe they have
demonstrated the existence of an antibody opposed to microorganismal albumin.
Kolle (1909) attempted to test the theory that intestinal parasites bore a relation
to endemic goiter. McCarrison (1909) was of the opinion that the agent of goiter was in
the intestinal tract, because of the prompt results obtained in his experience by the giv-
ing of a single or repeated doses of thymol. He (1911) tested this hypothesis experi-
mentally by mixing the feces of goitrous men with sterilized soil and he fouled water
with this mixture by pouring it through a specially constructed box. In one of these
boxes he placed 500 earthworms on the assumption that they might be an intermediary
host of the infecting agent. Water from the first box was given to six female goats and
from the second with the earthworms to seven female goats. These goats were permit-
ted to consume this highly polluted water for 64 days with the following results: First,
loss of weight due doubtless to confinement in a small hut for the 64 days of the experi-
ment; second, many of them suffered from diarrhea; third, 50 per cent of the animals
showed marked enlargement of the thyroid gland, most marked on the right side.
The thyroids of three goats showed no enlargement. The enlargements were of various
degree. McCarrison gives the average weight of the normal thyroid of the goat of
Gilgat as 10000" of the body weight. The enlarged gland of the goats in the experiment
weighed from ^gVg t° 7 0*0 o part of the body weight. In both batches receiving the
fouled water the results observed were the same.
Microscopical examination of the enlarged organs by McCarrison showed "various
degrees of dilatations of the vesicles and no alterations in the connective tissue stroma
of the enlarged glands. The hypertrophy was due wholly to the distension of the
vesicles with colloid and to the formation of new vesicles from intravesicular masses
of cells." He concludes: (i) An hypertrophy of the thyroid gland of goats may be
induced by infecting the water supply with feces from sufferers from goiter. It is at
present impossible to state whether this hypertrophy is due to the action of the infect-
ing agent of goiter or only to the organic impurity of the water thus contaminated.
(2) Earthworms do not appear to be concerned in the spread of goiter. (3) The micro-
scopic appearances described are the earliest changes in the formation of parenchyma-
tous goiter.
. One of the most interesting recent discoveries in relation to a parasitic thyroiditis
is found in the publication of Carlos Chagas (1911). This author, cited by Schitten-
helm and Weichardt, found in an insect, a Brazilian bedbug (barbeiro, Conochinus
megistus], a flagellate which he identified as part of the developmental cycle of Try-
panosoma minasense Chagas, which he had discovered in the silky monkey. If the
infected bedbugs were allowed to bite this variety of monkey the latter received a blood
infection with the organism. The bedbug is therefore the intermediary host and the
incubation period after the bite is eight days. Chagas undertook to determine the
original host for this organism and found in the State of Minas Geraes, especially in
CARCINOMA OF THE THYROID IN SALMONOID FISHES. 497
children, a flagellate disease which, when the patient was transferred to Rio Janeiro,
he was able to transfer to the silky monkey by means of the barbeiro. The charac-
teristic symptoms of the disease in the children were enlargement of the thyroid, the
stupefied appearance of the child, and enlargement of the lympahtic glands. He also
succeeded in inoculating guinea pigs with the flagellate organism by injecting the blood
of the infected children.
He divided the disease into an acute and a chronic form. The chronic form is char-
acterized by hypertrophy of the thyroid affecting one or both of the lobes of the thyroid
and frequently the isthmus. Even in young children the enlargement of the thyroid
may be very marked. He says that in some regions the disease is very widespread and
here infantilism and cretinism are very prevalent. All these individuals presented the
characteristic enlargement of the thyroid. The histologic picture of the disease is in
part an inflammatory reaction of the stroma of the thyroid with outspoken sclerosis.
In such cases the alveoli are small and the lumen reduced. The colloid is usually
decreased in amount and stains poorly. In the vesicles there appears to be desquama-
tion and degenerative changes of the epithelium which fill the lumina of the alveoli.
The islands of epithelium which normally lie between the vesicles appear to have been
increased by proliferation, in some covering extensive areas. Large cysts filled with
colloid characterize the last stages of the chronic form, with occasional calcification of
the cyst wall.
In cancer of various kinds intermediary carriers have been suspected. The well-
known association of cancer in Bilharzia disease with the important trematode parasite,
Distomum haematobium, is classic. Borrel in 1 906 reported having found very frequently
in mouse cancer, in the immediate neighborhood of or within the tumor, occasional
small nematode worms. These, he did not think, were themselves in etiologic relation
to the tumors, other than as possible carriers of a specific virus. This theory was
strengthened in his mind by finding in the left kidney of a rat, which died of a cancerous
tumor in the right kidney, a small cyst containing a very young cysticercus, which was
identified as belonging to the Tsenia crassicola of the cat. Upon the membrane of this
cyst, which was attached to the tissue of the kidney, he found a small tumor of identical
structure to that of the larger tumor of the right kidney.
In the second case, furnished him by Laveran, a rat died of a tumor of the liver
of the size of an orange, in the exact center of which was found a cyst with a tumor
growing out from it in all directions. This cyst contained a cysticercus which was
again identified as belonging to the Tsenia crassicola of the cat. Microscopically this
tumor was a large-celled sarcoma. Bipolar and multipolar karyokinetic figures were
very numerous. This tumor proved to be transplantable and had produced large
tumors for three or more generations. Borrel felt that the successful transplantation of
this tumor strongly indicated that the cysticercus had carried with it a virus which it was
possible to propagate with the cells. Finally he called attention to the possible relation
of helminthia and cancer and felt that this hypothesis was in accord with the frequent
tumors of the digestive tracts and the appendix. He thought that the endemic occur-
498 BULLETIN OP THE BUREAU OP FISHERIES.
rence of cancer in animals might be explained by the distribution of some nematode or
other carrier.
Regaud (1907) reported two rats in one of which he found at autopsy a general
sarcomatosis of the peritoneum. At the border of the liver hung a cyst which contained
a cysticercus. The neoplasm was a sarcoma with fusiform elements. Inoculation into
five rats remained negative. The second, an adult male, having been found dying
without known cause, was killed. In the peritoneum a tumor the size of a nut had devel-
oped in the large omentum. There were numerous miliary granulations around the
tumor. At the center of it was a smooth cavity containing a tapeworm 25 centimeters
long and living. Intraperitoneal inoculations made in five rats were negative. The
parasites in both cases were identified as cysticerci of the Tsenia crassicola of the cat. In
common with Borrel, Regaud felt that the cysticerci in these instances were the carriers
of a virus, as he had frequently found cysticerci in the liver of rats killed for histological
research without accompanying neoplasms.
That a virus of cancer is no longer hypothetical has been shown by the recent
demonstration by Peyton Rous in three varieties of sarcoma in chickens of a filterable
virus capable of producing type-true neoplasms. This agent passes through a medium-
grade Berkefeld filter. It is preserved by glycerin, has a killing point slightly higher
than the cells of the chicken, is not injured by freezing, and is killed at 55° C. The agent
can be preserved by drying the cells and can withstand grinding. After many months
the agent can be separated from the dried cells by filtration, or, in common with them,
on injection inaugurates at the point of trauma the growth of a malignant sarcoma of the
type from which the virus has been taken. Rous has separated the filterable virus from
a spindled-celled sarcoma (1910), an osteo-chrondro-sarcoma (1912), and a spindle-
celled (intracanalicular) sarcoma (1913) with peculiar arrangement of the cells. The
virus of the osteo-chondro-sarcoma possesses the remarkable quality of causing the
connective tissue with which it comes in contact to proliferate and specialize by forming
cartilage and bone. His experiments not only show the existence in these tumors of a
filterable virus but the existence for each type of a special virus. It is needless to point
out that the agent of goiter is also filterable, which fact should strengthen the theory
that the goiter agent is a living organism and not a soluble toxin.
Haaland, Loewenstein, von Wasielewski, and others have found helminthia in
mouse cancers.
The theory of Borrel regarding nematodes has recently been experimentally proven
by Fibiger (1913). Fibiger found in three rats in his laboratory large papillary growths
of the stomach, in all of which were many small nematode worms. These growths he
held to be fibroepithelial tumors, probably malignant, an opinion which was strengthened
by microscopic examination. The epithelial proliferation was found to have broken
through the muscularis mucosa, and the submucosa contained projections and islands
of squamous epithelium. To determine how frequent the disease might be in Copen-
hagen, he examined 1,144 rats without finding any evidence of the disease. Later his
attention was drawn to cockroaches as possible carriers of such nematodes, through an
article by Caleb in 1878, who found nematodes in the stomachs of rats after feeding
CARCINOMA OF THE THYROID IN SALMONOID FISHES. 499
them the cockroaches, Periplaneta orientalis. These he identified as Filaria rhytipleurites
of des Longchamps. After examining 61 rats from a locality in Copenhagen which
was infested with Periplaneta americana, he found similar worms in the stomachs of
40, of which 9 had well-developed tumors and 9 inflammatory reaction of the mucosa,
which he held to be the beginning or precancerous stage of the disease. Furthermore,
he reports that by feeding 57 laboratory rats with Periplaneta americana from the same
locality he found the worms in the stomachs of 54, in 7 of which were definite tumors
and 29 of which had the precancerous stage of the disease. Two of these tumors were
found certainly to have metastases, probably three. The metastases did not contain
the nematodes, and furthermore, Fibiger states that there is no direct relation between
the intensity or amount of proliferation and the location of the worms in the gastric
mucosa.
The life history of these worms is as follows : They live in the squamous epithelium
of the esophagus and stomach of the rat. In rare cases they are found in the epithelium
of the tongue and the mouth cavity. Here they reach the reproductive stage and eject
eggs which, with the desquamated epithelium, are carried out with the excreta. In the
excreta they are taken up by the cockroach Periplaneta orientalis, and in these insects
the eggs develop into free embryos, wander into the striated musculature of the pro-
thorax and the extremities. Here they remain for about six weeks or a longer time as
trichina-like spirally coiled larvae. If the cockroaches are consumed by the rats the
larvae are freed from their capsules and wander into the squamous epithelium of the
rat's stomach, occasionally into the esophagus or the epithelium of the mouth or tongue.
Here after two months the female begins to deposit eggs. The measurements of these
worms in the fully developed stage are, for the male, one-half to i centimeter long,
diameter, o.i to 0.16 millimeter; females, 4 to 5 centimeters long; diameter, 0.2 to
0.25 millimeter. The eggs are oval, clear, with double contour membrane, at the
poles slightly thicker than at the circumference. The eggs measure 0.06 by 0.04
millimeter. They contain a rolled-up embryo with annular divisions of the cuticle.
They have been identified as belonging to the genus Spiroptera. The male has a large
bursa, with two spicules of different lengths and four preanal, as well as four postanal
papillae, on each side, these characteristics serving to distinguish them from the Spiroptera
obtusa, as well as from the Filaria rhytipleurites of Galeb. It is therefore a new
nematode.
In the sections of the hyperplastic thyroids in our second series of experimental
dogs, we were interested to find in the capsule and in the substance of the thyroid small
tubercles measuring usually 0.3 by 0.35 millimeter, of strikingly uniform appearance.
At the periphery of these tubercles is a fibrous connective tissue capsule of thin and
flattened cells. Within the outer layer of flattened fibrous connective tissue a more
cellular structure composes the body of the tubercle. These are large fibroblasts of
spindle form with oval, vesicular nuclei. They have a general arrangement, as if per-
pendicular to the circumference. The center of the tubercle is composed of intercellular
substance with usually a zone of leucocytes, and by aid of serial sections, usually in the
center of these tubercles, one encounters a cross or oblique section of a small nematode
500 BULLETIN OF THE BUREAU OF FISHERIES.
worm. (Fig. 124.) Occasional tubercles will be encountered in which either the head
(fig. 123) or tail of this worm lies near the periphery, and in some instances a fully
formed tubercle has been encountered with cross sections of the worm lying without
the connective-tissue capsule usually coiled in undulating fashion. (Fig. 122.) The
worms appear to be of the same1 species. For the purpose of identification, sections of
the worms have been submitted to B. H. Ransom, Chief of the Zoological Division of
the Bureau of Animal Industry of the United States Department of Agriculture at
Washington. We are indebted to Dr. Ransom for the following notes :
After examining the preparations I fail to identify the parasite to which you call attention with
any known species. As it is quite different from a hookworm larva it is not Ancylostoma caninum or
any other species of hookworm, a possibility which would perhaps first suggest itself, inasmuch as the
larval stages of A ncylostoma en route to the alimentary tract are likely to be found in various tissues,
though apparently they have not yet been noted in the thyroid gland. As to other possibilities, so
far as I have been able to determine, no nematode has been recorded from the thyroid gland of dogs.
Furthermore , the form in question does not agree in morphology with any adequately described nema-
tode known to occur in the dog in any part of the body.
The nematodes in this case, which are sexually undeveloped, may be (i) immature stages of some
species which occur in its adult stage in the dog and whose larvae after gaining entrance to the body
perform more or less extensive migrations before reaching their final location, and would thus be com-
parable to Ancylostoma, whose larvae regularly migrate from the skin to the digestive tract, or to Spirop-
tera sanguinoknta, whose larvae, it is stated, sometimes migrate from the digestive tract to the blood
vessels and other rather remote locations where development to maturity may occur; (2) they may
conceivably belong to some species like Ollulanus tricuspis, whose young, according to Leuckart, may
either pass out of the body to become encysted in an intermediate host or penetrate into various tissues
of the original host and become encysted in the manner of Trichinella; (3) they may be the larval stage
of some species whose adult stage occurs in another host, the dog acting as a true though perhaps unusual
intermediate host; or (4) they may be present in the dog as the result of an accidental infection entirely
outside the normal life cycle, this case being comparable to that of the infestation of mice and other
animals with the larvae of Spiroptera sanguinolenta to which Seurat (1912, Compt. rend. Soc. de biol.,
Paris, v. 73, p. 279) has called attention. This author notes that these larvae which are found in cock-
roaches, instead of developing to maturity as when fed to dogs, if fed to white mice pass through the
wall of the digestive tract and become encapsuled in various organs without undergoing further devel-
opment. The possibility last suggested (4) is also comparable to that of the migrations of the larvae
of Ancylostoma duodenale, a human parasite, in dogs. The larvae of this species penetrate the skin of
dogs and in course of time may reach the intestine, undergoing a partial development which, however,
falls short of maturity.
As a rule when nematodes or other parasites are found in a given host it is to be presumed that
the animal is playing the part of a true host and that there is a more or less complete adaptation between
the host on one hand and the parasite on the other. The possibility, however, should noif be lost sight
of that larval nematodes of an unknown species found in a certain host, or of a known species found
in an unusual host, may represent individuals which have gone astray so far as the possibility of com-
pleting their normal life cycle is concerned. It is apparently true that nematodes which thus go astray
usually die before there is any development or any invasion of the tissues of the animal. That is,
nematodes entering the digestive tract of an animal which is unsuitable as a host as a rule quickly
succumb without doing any damage. This is, however, not the case with all species, for example,
Spiroptera sanguinolenta in mice, as noted above. Similarly in the case of nematodes whose normal
mode of entrance is through the skin it is to be presumed that they will not even enter the skin of an
unsuitable host, but such occurrences may not be very unusual. The case of Ancylostoma duodenale
already mentioned, and that of Strongyloides stercoralis, another human parasite, which behaves much
CARCINOMA OF THE THYROID IN SALMONOID FISHES. 501
as A . duodenale with reference to dogs, are sufficient to indicate that stray parasites may enter the body
through the skin as well as through the mouth, and perform extensive migrations through the tissues
and even undergo a partial development before they die. The possibilities as to the amount of damage
such stray parasites may do are interesting. They may, for instance, have more injurious effects on
the unusual host than on the animal to which they are specifically adapted, much as in the case of
various parasitic protozoa which do not injure certain animals considered to be their usual hosts, but
are very injurious to others considered unusual hosts. The two cases are of course not strictly com-
parable as there would be no multiplication, at least no repeated multiplication, in the case of the
nematode like that in the case of the protozoan. The introduction of microorganisms by nematode
larvae is another possible source of damage, and this applies not only in the case of stray parasites but
in the case of those entering their proper host animals. Many parasitic nematodes have plenty of
opportunity during the early stages of their free living existence while they are actively feeding upon
the organic materials in the medium, commonly fecal matter which surrounds them, to pick up injurious
microorganisms, and these it is quite conceivable may be carried with them on their later migrations
and finally deposited where damage will result. Looss (1911, Rec. Egypt. Govt. School Med., Cairo,
v. 4, p. 557), for example, suggests that Ancylostoma larvae which have developed in feces might retain
some bacteria in their intestine and evacuate these as soon as they arrive in the body of their host, and
that this if it occurred might have something to do with the skin lesions which accompany Ancylostoma
infections.
Returning to the nematodes in the thyroid of the dog, it has not seemed advisable to venture an
opinion as to the genus or even the family to which the parasites may belong. In order that they may
not be left nameless I have designated them as Agamonematodum gaylordi, thus placing them in a col-
lective group, which is used for convenience of reference to include various immature nematodes,
whose sexually mature stage is undetermined. The following brief description is based on an individual
the anterior portion of which is present in the sections on a slide labeled " Dog 17. K. 1-22-12.20, Nem.
2". (Fig. 123.)
AGAMONEMATODUM GAYLORDI.
Length uncertain, but apparently less than i millimeter; maximum width 35;*.. Head apparently
with 3 lips, each supplied with a small papilla. Diameter of head at level of papillae sofi, increasing to
24^ at a distance of 2o/« from the anterior end, then rather suddenly constricted to 20/1, after which the
diameter of the body gradually increases, reaching 32;* at the level of the nerve ring, which is located
about ioo/i from the anterior end of the body. Mouth very small, communicating directly, without
intervening larynx or mouth capsule, with the esophagus. Esophagus near its anterior end
measures about i6// in diameter, is then constricted slightly, corresponding with the constriction of
the body, and gradually increases again in diameter, attaining a size of about i8/t in the neighborhood of
the nerve ring. Length of esophagus uncertain, but exceeds i6o/z. The anterior end of the body is
supplied with narrow lateral cuticular wings, which extend posteriorly an unknown distance beyond
the esophageal region.
Host. — Dog (Canis familiar is}.
Location. — Thyroid gland in small tubercles.
Locality. — Craig Brook, Me.
The nematodes were not found in the two dogs examined in 1910, one of which had
marked thyroid hyperplasia and the other a nearly normal gland, but serial sections were
not available. In all (3) of the puppies which had marked hyperplasia and were given
drinking water in which were suspended scrapings (dog 16, dog 17, and dog 22) nema-
todes are present. In the white mongrel adult dog with the highest degree of diffuse
parenchymatous hyperplasia and degeneration (dog 18) they are also present. In the
control for this dog, the mother of the puppies, which received boiled water (dog 19),
they are not present. In the control puppy no. 21, which received boiled water, they
502 BULLETIN OF THE BUREAU OF FISHERIES.
are not present. In the second control puppy, no. 20, they are present. It is this
control, no. 20, which is described as having slight evidence of hyperplasia, but as this
dog received before the beginning of the final experiment, as did also the other controls,
water from pond 10, it is possible that it acquired the worms at that time. The mother
dog, no. 19, and the other control puppy, no. 22, also received pond 10 water and
showed no evidence of hyperplasia or nematodes.
There is apparently no direct connection between the hyperplasia of the thyroid
and the nematodes. As previously described, the hyperplasia of the thyroid in these
experimental animals is diffuse. If the nematodes have any direct relation to the experi-
mental hyperplasia of the thyroid thus produced, it is only as a carrier of the virus of the
disease in the manner which Borrel has suggested for tumors in mammals. That hyper-
plasia can result without nematodes or other possible carriers is shown by the fact that
we have not found anything of the sort in the hyperplasia of the thyroid in the rats,
induced with water and scrapings from Craig Brook. Bircher or the other authors
who have produced experimental goiter in animals have not noted the presence of nema-
todes. Nematodes in the region of the thyroid in fish are certainly not necessary to
the development of the disease in fish. We have in one or two instances found similar
tubercles usually lying in the subcutaneous tissue below the floor of the mouth in which
coiled-up nematode remains have been found. A portion of the cuticle of such a nema-
tode was sufficiently preserved so that its structure could be clearly made out. (Fig. 126.}
There is evidence in the dog thyroids that some of the nematodes perish. The finding
of disintegrating tubercles is subject to this interpretation. (Fig. 125.) It is therefore
possible that in the very early stages of the transmission of the disease it will be found
that such nematodes act as occasional carriers in this affection and that later they
disappear. A careful study of the intestinal contents of the fish and the scrapings
from the fish troughs will be included in the next stage of this investigation.
SUMMARY.
I. The present investigation of thyroid carcinoma among fish was begun by the
Director of the Gratwick Laboratory in furtherance of the inquiry of that institution
into the nature of cancer in man. Having brought it to the attention of the United
States Bureau of Fisheries through the President of the United States, an investigation
of wider scope resulted, based upon its interest and importance to fish culture and to
cancer research in general, and uniting the Federal and State resources as represented
by the Bureau and the Gratwick Laboratory.
Bonnet in 1883 described a gill disease in trout which is undoubtedly identical with
the subject of this inquiry, and is thus the first published reference to it, though the
nature of the disease was not at that time recognized. Scott in 1891 first identified the
disease as carcinoma, without recognizing its relation to the thyroid gland. Its origin
in the thyroid was first asserted by Plehn in 1902, who diagnosed it as adeno-carcinoma.
Pick in 1905 published the first extended study of the structure of the growths and
insisted on their carcinomatous nature. Gillruth in 1902 described it briefly as an
CARCINOMA OP THE THYROID IN SAL,MONOID FISHES. 503
epithelioma affecting the branchial arches and showed that it was widely distributed
among the hatcheries of New Zealand.
Gaylord began the study of the disease in 1908 and reported evidence pointing to
an infectious factor in its causation. Marine and I/enhart, as the result of studies in
1909 and subsequently, hold that the disease is endemic goiter and have failed to find
any specimens which they recognize as cancer.
The disease is widely distributed throughout the United States and probably occurs
more or less everywhere that artificial propagation of salmonoids is carried beyond the
early stages.
II. The normal thyroid follicles in salmonoids resemble those of the mammalian
thyroid, but the gland is not encapsulated and not so definitely confined within given
limits. In wild brook trout the largest masses of thyroid follicles are faintly macro-
scopic, and all the thyroid tissue is located in the neighborhood of and chiefly dorsal to
the ventral aorta between the first and third gill arches, and does not extend laterally
along the arches. The distribution is somewhat more restricted than that indicated by
Gudernatsch. Anomalous deposits frequently occur beneath the epithelium of the
jugular pit, but are rare elsewhere. The thyroid follicles of wild trout are regular in
shape, usually spherical or slightly elongate and in the typical or simplest condition its
epithelium is flattened or never higher than cuboidal.
III. Simple hyperplasia of the thyroid is met with in trout living under wild condi-
tions. The follicles are increased in number, are more irregular in shape, the colloid is
diminished, and the epithelium is in large part columnar. Such a hyperplasia exists
also in domesticated trout and is not to be distinguished from the earliest stages of
carcinoma of the thyroid. The immune Scotch sea trout as yearlings occasionally
exhibit this simple hyperplasia, and a few adults are found with colloid goiter. Sponta-
neous recovery from thyroid carcinoma in fish does not result in this picture of colloid
goiter.
IV. The first macroscopic evidence of the disease is usually found in an area of
hyperemia on the floor of the mouth (red floor). The first evidence of visible tumors
may be found at the branchial junction. Tumors may protrude in various directions,
at the branchial junction, in the floor of the mouth, or to either side of the gill region.
Independent tumors develop in the jugular pit, a region which frequently contains
deposits of normal thyroid tissue. The first microscopic evidence of the disease is
found to occur in individual follicles, usually those nearest a large vessel. A small
group of altered follicles surrounded by normal follicles is frequently found in the early
stages. The epithelium is high cubical or columnar, the protoplasm and nuclei stain
deeply. Colloid is diminished or absent, the vessels of the stroma hyperemic. Budding
of the wall of the follicle next occurs, forming isolated npw follicles of irregular type,
and papillary projections into the follicles. As the gland is not encapsulated, newly
formed tissue grows between the muscle planes and fills in the areolar spaces. At this
stage karyokinetic figures are common, the epithelium is high columnar, and frequently
there are several layers of epithelium in a single follicle. Proliferation may now have
504 BULLETIN OF THE BUREAU OP FISHERIES.
reached a sufficient amount to produce the red-floor stage. Bone, cartilage, and muscle
are invaded. The growth no longer seeks the paths of least resistance.
In the visible tumor stage there is a remarkable variation in the character of the
proliferation. All the various types occur in one tumor. They may be divided into
alveolar, tubular, and solid, and combined with papillary and cystic types. Frequently
small adenomatous structures of malignant appearance are found grading and infil-
trating the surrounding thyroid structure of less malignant appearance. Occasionally
islands of normal thyroid tissue have been found in the bone spaces or cavities of the
bone where the entire surrounding structure was replaced by thyroid carcinoma. True
infiltration of bone, cartilage, vessel wall, muscle, and skin has been demonstrated.
Occasionally tumors are met with which present the appearance of so-called sarco-
carcinoma of the thyroid in mammals; a background of spindle cells resembling sarcoma
with occasional alveoli.
Growths upon the apex of the lower jaw are either implantations or metastases.
A marked similarity of the primary tumor in the thyroid region with the growth upon
the tip of the jaw in one case studied indicates that this is probably metastasis formation
at the site of an injury. An undoubted case of metastasis formation is found in a tumor
growing in the intestinal wall at the lower end of the intestinal tract, which infiltrated
the muscularis mucosa of the intestinal wall, of characteristic thyroid carcinoma struc-
ture, large irregular follicles lined with columnar epithelium, occasionally containing
colloid. Portions of the tumor present an appearance closely approximating the least
malignant appearing primary tumors. The character of this growth and the region in
which it occurred shows conclusively that it is a metastasis.
A comparison of the various types of thyroid carcinoma of the Salmonidge shows
that they approximate in type three of the groups made by Langhans for carcinoma of
the thyroid in mammals, viz, proliferating struma, carcinomatous struma, and malignant
papilloma.
V. Three examples of the disease have been found in wild fish in the United States.
One occurred in a brook trout which may have been planted from a hatchery, one in
a landlocked salmon, and one in a whitefish. None of the species of whitefishes is fed
or reared artificially.
VI. The disease has been observed in 16 species of salmonoids, or in hybrids made
among these.
The geological formation at the sources of the water supplies in which the disease
occurs has apparently nothing to do with its origin, nor has the dissolved content of
the water.
The disease is usually endemic and occasionally epidemic. It occurs in ponds and
troughs, of whatever construction, in which fish are held, reared, and fed the ordinary
proteid foods of fish culture, viz, raw liver, heart, lungs, and other meats. It shows a
tendency to increase from above downward in the course of a given water flow. Hybrids
of the Pacific salmon are especially susceptible and show a high incidence. When
endemic, the course of the disease is slow and chronic, with a low death rate made
indeterminate by complication with intercurrent or terminal infection and other
causes of death. The incidence of tumors varies greatly and increases with the age of
CARCINOMA OF THE) THYROID IN SAIyMONOID FISHES. 505
the fish. Macroscopically visible growths have not been seen in fish under about five
months of age. Anemia and cachexia, sometimes extreme in degree, are a frequent
but not constant accompaniment of the disease. Immunity is strikingly exhibited not
only among species, as the Scotch sea trout, but with given lots of a susceptible species.
Recovery or regression occurs when affected fish are removed from domestication to
wild conditions and also in fish in ponds in which the disease was acquired.
VII. Feeding of fish tumors, or of human cancer, to brook trout has not during a
period of several months produced the slightest evidence of the disease attributable to
this feeding. The intimate association of susceptible trout with trout tumor material
in standing water, or with tumor fish in circulating unchanged water, has brought only
negative results. The fish tumor has not yet been successfully transplanted, but
implants have grown slightly and were alive at the end of three months. The tumor
extract is highly toxic to trout when injected into the thyroid region or subcutaneously.
Wild brook trout brought from the wilderness and confined in cement tanks and
fed raw heart or raw liver have developed microscopic evidence of the disease by the
end of the first year, and visible carcinoma between the first and second year. The
feeding of cooked liver retarded the process. Spontaneous regression occurred in a
high percentage of the meat-fed fish by the end of the second year. Similar trout fed
upon marine fish, vegetable food, or a combination of mussels and live maggots retained
their normal thyroids.
VIII. Either of the elements iodine, mercury, or arsenic dissolved as salts in the
water in which the fish are living interrupts the progress of the disease and restores the
thyroid epithelium to a condition approximating the normal. Recognizable effects are
produced within a few days. Visible tumors are markedly affected and may be much
reduced in size. Iodine and mercury are effective even when diluted by many millions
of parts of water. Iodine is effective when introduced into the digestive tract as well
as through the medium of the water. Negative results were obtained with thymol by
both these methods of administration.
IX. The administration to dogs of mud and water from fish ponds in which thyroid
carcinoma was endemic gave suggestive evidence that the water and mud contained an
agent capable of producing marked changes in the thyroid. Scrapings from the inside
of old wooden fish troughs in which thyroid carcinoma was constantly produced gave
positive results. Four dogs were given for six months water to drink in which these
scrapings were immersed. All developed marked thyroid hyperplasia and three of them
enlarged thyroids. The thyroids of the three control animals remained of normal size.
Two of them were normal in structure while one showed slight evidence of hyperplasia,
probably referable to a previous experiment.
Rats given for six months mud and water which had been taken from ponds in which
thyroid carcinoma was prevalent and transported several hundred miles gave negative
results. Rats given for four months water from the fish trough scrapings, also trans-
ported as above, produced results similar to those obtained with the dogs but less marked
in degree.
8207° — X4 IO
506 BULLETIN OF THE BUREAU OF FISHERIES.
X. In the hyperplastic thyroids of three puppies and one adult dog which were
given pond mud and water, or water from fish-trough scrapings, minute nematode worms
were found immediately beneath the capsule or in the .substance of the thyroid. The
worms were surrounded by connective tissue tubercles. In two instances only remains
of small nematode worms were found in the thyroid region of brook trout with carcinoma
of the thyroid undergoing regression. If these worms have any etiological significance
it must be merely as carriers of a causative agent.
CONCLUSIONS.
1 . The disease known as gill disease, thyroid tumor, endemic goiter, or carcinoma of
the thyroid in the Salmonidae, is a malignant neoplasm.
2. The disease occurs in fish living under conditions of freedom in populated areas.
3. When introduced into fish-breeding establishments it becomes endemic with
occasional epidemic outbreaks.
4. Normal fish taken from the wilderness may be made to acquire the disease when
placed in fish-breeding establishments where the disease is endemic.
5. The feeding of uncooked animal proteid favors and the feeding of cooked animal
proteid retards the disease as compared with the uncooked. Feeding alone is not an
efficient cause. It must be combined with an agent transmitted probably through the
water or food, or both.
6. By scraping the inner surface of water-soaked wooden troughs in which the disease
is endemic, an agent may be secured which from its action upon the mammalian thyroid
when administered through drinking water is no doubt the cause of the disease in the
fish confined in these troughs.
7. The agent is destroyed by boiling.
8. Fish in all stages of the disease are favorably affected in the direction of cure by
the addition to the water supply in suitable concentration of mercury, arsenic, or iodine.
9. The effect of mercury, arsenic, and iodine in carcinoma of the thyroid in fish
and the subsequent positive experiments with metals in mammalian cancer are probably
the expression of a therapeutic relation of these elements to carcinoma.
10. Certain species of the Salmonidae have an almost complete natural resistance to
the disease.
11. Certain lots of fish of susceptible species show a high degree of immunity to
the disease.
12. Spontaneous recovery occurs in a considerable percentage of individuals.
13. Removal from ponds in which the disease is endemic to natural conditions,
or a change to more natural food, increases the percentage of spontaneous recoveries.
14. Spontaneous recovery appears to confer a degree of immunity against recurrence.
15. The percentage of spontaneous recoveries in the early stages of the disease
appears to be higher than in the later stages of the disease.
1 6. The incidence of the disease increases with the age of the fish, at least up to
five years.
CARCINOMA OF THE THYROID IN SALMONOID FISHES. 507
17. Thyroid enlargement and changes presenting at the end of five months a picture
of diffuse parenchymatous goiter were induced in mammals by giving them water to
drink in which had been suspended scrapings from troughs in which the disease is
endemic. Control animals which receive the same water boiled failed to develop thyroid
changes. That these enlargements and changes are the first stages in mammals of the
same disease which occurs in the fish inhabiting the troughs from which the scrapings
were obtained, is an inference which we believe further experiments will justify.
1 8. The disease is endemic in a very high percentage of all trout hatcheries in the
United States.
19. The occurrence of the disease in wild fish, its introduction into fish-cultural
stations, its localization in certain troughs or water supplies, the method of its spread,
its transmission to mammals, the efficacy of three well-known inorganic germicides in
the treatment of the disease, the destruction of the agent by boiling, the phenomena of
spontaneous recovery and immunity, strongly indicate that the agent causing the
disease is a living organism.
20. No evidence has yet been produced to indicate the direct transmission of the
disease from individual to individual.
21. In many of its phases the disease is identical with endemic goiter. As there
is no line of demarcation between what is called endemic goiter and what we believe we
have clearly shown is cancer of the thyroid, we hold that endemic goiter and carcinoma
of the thyroid in the Salmonidae are the same disease.
ZUSAMMENFASSUNG.
I. Die gegenwartige Untersuchung des Schilddriisen-Krebses unter den Fischen
wurde von dem Leiter des Gratwick-Laboratoriums eingeleitet zwecks Foerderung der
Untersuchungen dieses Institutes betreffs der Natur des Krebses beim Menschen.
Nachdem durch die Vermittlung des Praesidenten der Vereinigten Staaten das Interesse
unserer Central-Bureaus fuer Fisch-Zucht gewonnen war, nahm die Untersuchung eine
betrachtliche Ausdehnung gestiitzt auf die Wichtigkeit derselben fuer die Fisch-Zucht
und fur die Krebs-Forschung im Allgemeinen. So wurden fuer den Zweck die Huelfs-
kraefte des Landes (Centralbureau fuer Fisch-Zucht) und des Einzel-Staates (Grat-
wick Laboratorium) vereinigt.
Bonnet beschrieb im Jahre 1883 eine Kiemen-Erkrankung der Forelle, welche
zweifellos mit dem Gegenstand unserer Untersuchungen identisch ist, und dies ist die
erste diesbezuegliche Mitteilung, wenn auch die Natur der Erkrankung damals nicht
erkannt worden war. Scott erklaerte die Erkrankung im Jahre 1891 als erster fuer
Krebs, ohne ihre Beziehung zur Schilddruese zu erkennen. Ihr Entstehen in der
Schilddruese wurde zuerst von Plehn im Jahre 1902 behauptet, welcher die Krank-
heit als ein Adeno-Carcinom diagnostizierte. Pick veroeffentlichte als erster im Jahre
1905 eine eingehende Erforschung der Struktur dieser Neubildungen und erklaerte
sie absolut fuer Krebs-Tumoren. Gilruth beschrieb dieselben in 1902 als Epitheliom
der Kiemenboegen und wies nach, das sie in den Fisch-Brutanstalten Neu-Seelands
sehr verbreitet waren.
508 BULLETIN OP THE BUREAU OF FISHERIES.
Gaylord began das Studium der Erkrankung im Jahre 1908 und berichtete Tat-
sachen, welche auf eine Infektion als Ursache hinwiesen. Marine und Lenhart behaupte-
ten im Jahre 1909 und spaeter als das Resultat ihrer Untersuchungen, dass die Krank-
heit ein endemischer Kropf waere. Sie konnten in ihren Praeparaten keinen Krebs
feststellen.
Die Erkrankung ist in den Vereinigten Staaten weit verbreitet und kommt wahr-
scheinlich mehr oder weniger ueberall vor, wo die Ziichtung von Salmoniden ueber das
frueheste Stadium hinaus fortgefuehrt wird.
II. Die Follikel der normalen Schilddruese in der Lachs-Gruppe aehneln denen
der Saeugetier-Schilddruese, aber die Druese ist nicht eingekapselt und nicht so scharf
abgegrenzt. Bei der wilden Bach-Forelle sind die groessten Haufchen der Follikel
makroskopisch eben wahrnehmbar, und das gesammte Schilddruesengewebe ist in
der Naehe der Ventral-Aorte hauptsaechlich dorsalwaerts derselben gelagert zwischen
dem ersten und dritten Kiemenbogen. Sie dehnen sich nicht lateralwaerts langs den
Kiemenboegen aus. Die Lage is mehr beschraenkt als nach der Angabe von Guder-
natsch. Haeufig sieht man anomale Follikel-Anhaeufungen unter dem Epithel der
Jugular- Vertiefung, aber kaum irgend wo anders. Die Schilddruesen-Follikel der
wilden Forelle sind von regelmaessiger Gestalt, gewoehnlich kugelig oder langlichrund,
in der typischen oder einfachsten Form haben sie ein flaches, jedenfalls nie hoeher als
wurfelformiges Epithel.
III. Einfache Hyperplasie der Schilddruese findet man bei der wilden Forelle.
Die Follikel sind zahlreicher, unregelmassiger in Form, das Colloid ist vermindert und
das Epithel ist zum grossen Teil saulenformig. Solch eine Hyperplasie kommt auch
beider zahmen Forelle vor, und dieselbe lasst sich nicht von dem friihsten Stadium
des Schilddruesen-Krebses unterscheiden. Die immune See-Forelle (Salmo trutta)
zeigt gelegentlich im ersten Jahr diese einfache Hyperplasie und im ausgewachsenen
Zustand findet man einzelne mit colloidem Kropf. Spontanheilung des Schilddriisen-
Krebses beim Fisch zeigt nicht dieses Bild des colloiden Kropfes.
IV. Das erste makroskopische Anzeichen der Erkrankungen ist gewohnlich ein
hyperamischer Fleck in dem Boden der Mundhohle (red floor) . Das erste Zeichen einer
sichtbaren Neubildung findet man an der Kiemenbogen-Vereinigung. Deutliche Tu-
moren konnen entweder hier oder auf dem Boden der Mundhohle oder zu beiden Seiten
der Kiemenbogen hervorwachsen. Selbstandige Tumoren entwickeln sich in der Jugular-
Vertiefung, woselbst nicht selten Anhaufungen von normalem SchilddrusenOewebe zu
finden sind. Die ersten mikroskopischen Anzeichen der Erkrankung findet man in
vereinzelten Follikeln, gewoehnlich denen welche einem grossen Blutgefass benachbart
sind. Eine kleine Gruppe von veranderten Follikeln sieht man oft im Fruhstadium
umgeben von normalem Gewebe. Das Epithel ist wiirfel- oder saulenformig, das Proto-
plasma und die Kerne im gefarbten Praparat sind stark gefarbt. Colloid ist vermindert
oder nicht vorhanden, die Gefasse des Stromas sind hyperamisch. Demnachst stellt
sich Wucherung der Follikel wand ein,es bilden sich neue Follikel von unregelmassiger
Gestalt und papillenartige Auswiichse in die Follikeln. Da die Druse keine Kapsel hat,
wachst das neugeformte Gewebe in die Muskelbiindel hinein und f ullt die Areolar-Raume.
CARCINOMA OF THE THYROID IN SALMONOID FISHES. 509
In diesem Stadium sind karyokinetische Bilder sehr gewohnlich, das Epithel ist hoch-
saulenformig, haufig findet man mehrere Epithel-Lagen in einem einzelnen Follikel. Die
Wucherung kann jetzt so weit fortgeschritten sein, dass sie das "rote Boden" Stadium
erreicht. Die Neubildung verfolgt nun nichtmehr den Weg des geringsten Widerstandes.
In diesem Stadium des deutlich sichtbaren Tumors zeigt derselbe eine auffallende
Character- Verschiedenheit im Wachstum. Sammtliche Typen konnen in einem Tumor
vorkommen. Man kann alveolare, tubulare und solide Formen unterscheiden, welche
im Verein mit papillaren und cystischen Typen auftreten konnen. Haufig findet man
kleine adenomatose Gewebshaufchen von bosartigem Aussehen, welche in das umge-
bende, weniger bosartig aussehende Schilddriisengewebe hineinwachsen und dasselbe
durchdringen. Manchmal fanden sich Inseln von normalem Schilddriisengewebe in den
Knochenraumen oder in den Knochenhohlen, wo das gesammte umgebende Gewebe
durch Schilddrusen-Krebs ersetzt war. Es liess sich wirkliche Infiltration des Knochens,
des Knorpels, der Gefass-Wandung, des Muskels und der Haut nachweisen. Manchmal
stosst man auf Tumoren, welche das Bild des sogenannten Sarco-Carcinom der Saugetier-
Schilddriise geben; ein Hintergrund von Spindel-Zellen wie beim Sarkom mit einer
Alveole hier und da. Tumoren an der Spitze des Unterkiefers sind entweder Implanta-
tionen oder Metastasen. Eine deutliche Ahnlichkeit des primaren Tumors in der Schild-
driisen-Gegend mit der Wucherung an der Spitze des Kiefers, welche wir in einem Falle
untersuchten, zeigte dass letztere wahrscheinlich eine Metastase an einer verletzten
Stelle war. Einen unzweifelhaften Fall von Metastasis fanden wir in einer Neubildung
in der Darm-Wandung am untern Ende des End-Darms. Dasselbe wuchs in die Muscu-
laris mucosa des Darms, zeigte den typischen Schilddriisen-Krebs-Bau, grosse unregel-
massige Follikel gesaumt mit saulenartigem Epithel, hier und da etwas Colloid. Teile
derGeschwulst sehen aus wie die am wenigsten bosartig aussehenden primaren Tumoren.
Der Character dieser Neubildung und die Localitat beweisen deutlich dass es eine Meta-
stase ist. Eine Vergleichung der verschiedenen Formen des Schilddriisenkrebses in den
Salmoniden zeigt, dass sie im Grossen und Ganzen den drei Gruppen entsprechen, welche
Langhans f uer den Schilddriisenkrebs bei Saugetieren auf stellt, namlich : Wuchernder
Kropf , krebsartiger Kropf und bosartiges Papillom.
V. Drei Falle der Erkrankung haben wir in den Vereinigten Staaten beim Fisch im
Wildzustand gefunden, einen bei einer Bach-Forelle, welche vielleicht aus einer Fisch-
Ziichterei verpflanzt worden war. Die zwei andere betraf einen "Weissfisch" (Core-
gonus) und ein Lachs (Salmo sebago). Bei dem Coregonus findet weder kunstliche Fiit-
terung noch Ziichtung statt.
VI. Die Erkrankung wurde in 16 Arten der Familie "Lachs" beobachtet oder in
deren Kreuzungsformen. Die geologische Formation des Bodens in der Umgebung
der Gewasser und ihrer Quellen, in denen die Krankheit an Fischen beobachtet worden
ist, hat wahrscheinlich nichts mit ihrem Ursprung zu thun, ebenso wenig die im Wasser
gelosten Bestandteile. Die Erkrankung ist gewohnlich endemisch, zuweilen epidemisch.
Sie kommt vor in Teichen und Wasserbehaltern, was immer auch die Construction
sein mag, in welchen Fische gehalten, geziichtet und mit der gebrauchlichen Pro-
teinhaltigen Nahrung gefiittert werden: Roher Leber, Herz, Lunge und anderen
animalen Bestandteilen. Beim Verfolgen eines Flussgebiets stromabwarts sieht man
510 BULLETIN OF THE BUREAU OF FISHERIES.
eine Zunahme in der Affektion. Kreuzungen mit dem Lachs des Stillen Oceans sind
besonders emfanglich und zeigen eine hohe Krankheits-Ziffer. Die endemische Form
verlauft langsam, chronisch mit einer niedrigen Sterberate, welche selbst sicherer fest-
zustellen ist wegen der Complication mit intercurrenten Affektionen und der schliesslichen
Infektion. Das Vorkommen des Tumors schwankt sehr und nimmt mit dem Alter des
Fisches zu. Makroskopisch sichtbare Neubildungen waren erst nach dem fiinften
Lebensmonat des Fisches bemerkbar. Anamie und Cachexie, zuweilen sehr hochgradig,
waren eine haufige aber nicht constante Begleit-Erscheinung. Immunitat zeigt sich in
auffallender Weise nicht nur bei einzelnen Arten wie bei der See-Forelle, sondern auch
bei Arten welche fur die Erkrankung empfanglich sind. Heilung oder Riickbildung
kommt vor, wenn die erkrankten Individuen in Verhaltnisse absoluten Naturzustandes
iibergef iihrt werden und auch wenn Fische in Teichen weiter gehalten werden, in welchen
sie erkrankten.
VII. Fiittern von Bachforellen mit Fisch-Tumoren oder mit Krebs vom Menschen
wahrend einer Periode von meheren Monaten gab nicht den geringsten Beweis, dass eine
Erkrankung solchem Fiittern zuzuschreiben sei. Innige Beriihrungen von empfang-
ilichen Forellen mit Forellen-Tumor-Material in stagnierendem Wasser oder mit tumor-
behafteten Fischen in circulierendem unverandertem Wasser brachte uns nur negative
Resultate. Der Fischtumor hat sich noch nicht mit Erfolg transplantieren lassen, aber
Implantationen gelangen bis zu einem gewissen Grade, und dieselben waren nach Verlauf
von 3 Monaten lebensfahig. Der Tumor-Extract ist hochgradig giftig fur die Forelle,
wenn derselbe in die Schilddriise oder subcutan injiciert wird. Wilde Forellen wurden
aus ihrer natiirlichen Umgebung in Cement-Behalter gebracht und mit ungekochter
Leber and Herz gefiittert. Dieselben zeiten die mikroskopisch nachweisbare Erkran-
kung am Ende des ersten Jahres und sichtbaren Krebs zwischen dem ersten und zweiten
Jahr. Fiitterung mit gekochter Leber verzogerte den Prozess. Spontane Riickbildung
war in einem grossen Prozentsatz der fleischgefiitterten Fische am Ende des zweiten
Jahres nachweisbar. Forellen derselben Art mit Salzwasser-Fisch, Vegetabilien oder
einer Mischung von Muscheln und lebenden Wiirmern genahrt behielten ihre normale
Schilddriise.
VIII. Jod, Quecksilber und Arsen in ihren Salzverbindungen im Wasser gelost, in
welchem die Fische leben, unterbrechen das Fortschreiten der Erkrankung und stellen
beinahe den Normal-Zustand des Schilddriisen-Epithels wieder her. Ein deutlicher
Einfluss ist schon nach wenigen Tagen bemerkbar. Sichtbare Tumoren werden
wahrnehmlich beeinflusst und konnen betrachtlich schrumpfen. Jod und Quecksilber
sind schon im millionenfacher Verdiinnung wirksam. Jod ist wirksam, wenn in den
Verdauungstractus gebracht und durch die Vermittlung des Wassers. Nach beiden
Richtungen hin waren Versuche mit Thymol ohne Einfluss.
IX. Schlamm und Wasser von Fischteichen, in welchen Schilddriisenkrebs ende-
misch war, wurde an Hunde verfiittert. Es zeigte sich, dass das Wasser ein Agens
enthielt, welches imstande war, deutliche Veranderungen in der Schilddriise zu verur-
sachen. Material, welches von der Innenseite alter Fischbehalter abgekratzt worden
war, in denen bestandig Schilddriisenkrebs produciert worden war, gab positive Resultate
CARCINOMA OF THE THYROID IN SALMONOID FISHES. 511
Vier Hunde wurden 6 Monate lang mit Wasser getrankt, dem dieses Material beigesetzt
war. Sie zeigten sammtlich ausgesprochene Hyperplasie der Schilddriise, und drei
batten vergrosserte Schilddrusen. Die Schilddrusen der 3 Control-Tiere blieben normal
in Grosse. Zwei davon waren normal in Bau, wahrend eine leichte Hyperplasie zeigte,
wahrscheinlich aus Griinden eines friiheren Experiments. Ratten wurden 6 Monate
lang mit Schlamm und Wasser aus Teichen gefiittert, in denen Schilddriisenkrebs vor-
herrschend war. Dies Wasser musste mehrere hundert Meilen transportiert werden.
Das Resultat war negativ. Das obenerwahnte abgekratzte Fischbehalter material
wurde 4 Monate lang in Wasser an Ratten verf iittert. Das Wasser wurde ebenfalls einige
hundert Meilen transportiert. Das Resultat war ahnlich wie bei den Hunden, nur
nicht so ausgesprochen.
X. In den hyperplastischen Schilddrusen von drei jungen und einem ausgewach-
senen Hund, welche mit Wasser und Schlamm aus Fischteichen und Kratzmaterial aus
Fischtrogen getrankt wurden, fanden wir kleinste Nematoden unmittelbar unter der
Kapsel oder in der Substanz der Schilddriise. Die Wiirmer waren von Anhaufungen
von Bindegewebe eingeschlossen. In zwei Fallen wurden nur Uberreste von kleinen
Nematoden in der Schilddriisengegend bei Bachforellen gefunden mit einem Schild-
driisenkrebs, der sich in der Riickbildung befand. Wenn diese Nematoden eine aetio-
logische Bedeutung haben, so kann es nur die sein, dass sie Trager eines ursachlichen
Agens sind.
SCHLUSSFOLGERUNGEN.
1 . Die Krankheit, welche unter dem Namen Kiemen-Krankheit, Schilddriisentumor,
endemischer Kropf oder Krebs der Schilddriise bei der Lachs-Familie bekannt ist, ist eine
bosartige Neubildung.
2. Die Krankheit findet sich bei Fischen, die unter natiirlichen Bedingungen in
bewohnten Gebieten leben.
3. In Fisch-Ziichtereien eingefiihrt wird sie endemisch und bricht zuweilen in
Epidemien aus.
4. -Normale Fische der Wildnis entnommen konnen an der Affektion erkranken,
wenn sie in Fisch-Anstalten gebracht werden, in welchen dieselbe endemisch ist
5. Die Fiitterung mit ungekochtem Proteid Material vom Tier begiinstigt, die mit
gekochtem verzogert den Ausbruch der Krankheit. Fiitterung allein ist nicht eine wirk-
same Ursache. Es muss dazu kommen ein anderes Agens, das wahrscheinlich durch
Wasser oder durch Nahrung oder durch beides iibermittelt wird.
6. Durch Ausschaben der Innenflache holzerner wasserdurchtrankter Fisch-
Bottiche, in welchen die Krankheit endemisch ist, erhalt man ein Agens, welches nach
der Wirkung auf die Saugetier-Schilddriise durch Vermittlung von Trinkwasser zu
urteilen ohne Zweifel die Ursache der Erkrankung der Fische ist, welche in diesen
Behaltern gehalten werden.
7. Durch Kochen wird dasselbe zerstort.
8. In alien Stadien der Erkrankung werden Fische giinstig beeinflusst, wenn man
dem Wasser in gewisser Verdiinnung Quecksilber, Arsen oder Jod zusetzt.
512 BULLETIN OF THE BUREAU OF FISHERIES.
9. Die Wirkung des Quecksilbers, Arsens und Jods auf Schilddriisenkrebs beim
Fisch und die daraufhin vorgenommenen erfolgreichen Versuche mit Metallen an
Saugetieren sind wahrscheinlich der Ausdruck einer Heilwirkung dieser Elemente beim
Krebs.
10. Gewisse Arten der Salmoniden haben beinahe eine vollige natiirliche Wider-
standsfahigkeit gegen die Erkrankung.
1 1 . Manche Fische von empfanglichen Arten zeigen einen hohen Grad vom Immu-
nitat gegen die Krankheit.
12. Spontanheilung koramt in einer betrachtlichen Anzahl von Individuen vor.
13. Ubertragung aus Teichen mit endemischer Erkrankung in natiirliche Umgebtmg
oder Ubergang zu mehr natiirlicher Nahrung vermehrt den Prozentsatz der Spontan-
heilungen.
14. Spontan-Heilung scheint einen gewissen Grad von Schutz gegen Riickfall zu
verleihen.
15. Der Prozentsatz der Spontan-Heilungen in den Friihstadien der Krankheit
scheint hoher zu sein als in den spateren Stadien.
1 6. Das Vorkommen der Krankheit nimmt mit dem Alter des Fisches zu wenigstens
bis zum 5ten Jahr.
17. Schilddriisen-Vergrosserung und Veranderungen, welche nach Verlauf von 5
Monaten das Bild eines diffusen parenchymatosen Strumas darboten, wurden bei
Saugetieren erzeugt, wenn man ihnen Wasser zu trinken gab mit ausgeschabtem Material
von Fischbottichen, in welchen die Krankheit endemisch war. Controll-Tiere, welche
dasselbe Wasser gekocht erhielten, zeigten keinerlei Veranderungen an der Schilddriise.
Dass diese Vergrosserungen und Veranderungen an Saugetier-Schilddriisen die ersten
Stadien derselben Erkrankung sind, welche bei Fischen vorkommen, welche die obener-
wahnten Bottiche bewohnt haben, ist ein Schluss, welchen nach unserer Uberzeugung
weitere Versuche rechtfertigen werden.
1 8. Die Erkrankung ist zu einem hohen Prozentsatz in alien Forellen-Zuchtereien
der Vereinigten Staaten endemisch.
19. Das Vorkommen der Krankheit beim wilden Fisch, ihre Einfuhnmg in Fisch-
Ziichtereien, ihre Localisation in gewissen Bottichen oder Wasserlaufen, die Methode
ihrer Verbreitung, ihre Ubertragung auf Saugetiere, die Wirksamkeit von 3 wohlbe-
kannten Germiciden inorganischer Natur bei der Behandlung der Krankheit, die Zer-
storung des Agens durch Kochen, die Erscheinungen der Spontan-Heilung und der
Immunitat, weisen dringend darauf hin, dass das ursachliche Moment der Krankheit ein
lebender Organismus ist.
20. Es ist bisher kein Nachweis geliefert, dass die Krankheit von einem Individuum
auf das andere iibertragen wird.
21. In einer Reihe von Entwicklungs-Phasen ist die Krankheit identisch mit ende-
mischem Kropf. Da sich eine scharfe Grenze zwischen sogenanntem endemischem
Kropf und dem was wir als Krebs der Schilddriise auffassen und bewiesen zu haben
glauben, nicht ziehen lasst, so behaupten wir, dass endemischer Kropf und Schilddriisen-
Krebs bei den Salmoniden ein und dieselbe Krankheit ist.
CARCINOMA OF THE THYROID IN SALMONOID FISHES.
RESUME.
I/investigation, dont les pages suivantes sont un compte-rendu, du carcinome de
la glande thyroi'dienne chez les poissons a e"te entreprise par le directeur du Gratwick
Laboratory dans le cours des recherches du laboratoire sur la nature du cancer chez
Phomme. Le President des Ktats-Unis ayant eu son attention appel£e sur ce travail
a instruit le bureau des poissons d'y prater son concours, de sorte que les ressources des
Etats-Unis et de 1'Etat de New York, represented par ce bureau et le Gratwick Labora-
tory, 6tant re"unies, il en a resulte une investigation plus e"tendue de grand inte'ret et
de grande importance autant pour la pisciculture que pour les recherches sur le cancer.
Bonnet, en 1883, de"crit une maladie des branchies chez la truite, laquelle est sans
doute identique avec le sujet de ce travail. Cette description est done la premiere
publication sur ce sujet, quoique la nature de la maladie ne fut pas alors reconnue.
Scott en 1891 fut le premier a reconnaitre la maladie comme carcinomateuse sans toute-
fois reconnaitre sa relation avec la glande thyroide. Son origine dans la glande thyroide
fut avancde en premier lieu par Plehn en 1902, elle en fit le diagnostic de Tad^no-car-
cinome. Pick publia en 1905 la premiere e"tude un peu complete sur la structure de
ces tumeurs et insista sur leur nature cancereuse. Gillruth en 1902 le de"crit comme
une e"pitheliome ayant siege dans les arcs branchiaux et dit qu'on le trouvait dans la
plupart des £tablissements de pisciculture de la Nouvelle-Zelande. Gaylord com-
men^a son e"tude de la maladie en 1908 et fit un rapport dans lequel il attira 1' attention
sur la nature infectieuse de la cause. Marine et Lenhart comme re"sultat de leurs etudes
commencees en 1909 considerent la maladie comme e"tant un goitre ende"mique et disent
qu'ils n'ont pas trouve" de sujets dans lesquels ils ont trouve aucun sympt6me de cancer.
La maladie est grandement r£pandue a t ravers les Etats-Unis et existe probable-
ment plus ou moins partout ou I'elevage artificiel des salmonid£es est continue" plus
loin que dans leur £tat primitif.
II. Les follicules thyroidiens chez les salmonide'es ressemblent a ceux des mamma-
liens, mais la glande n'est pas encapsulee ni si limite'e dans sa situation. Chez les truites
de ruisseaux sauvages les plus grandes collections de follicules sont a peine macroscopi-
quement visibles, et tout le tissu thyroi'dien est place" aux alentours de 1'aorte ventrale
du cote" dorsal entre les premier et troisieme arcs branchiaux et ne s'6tend pas laterale-
ment le long de ces arcs. Leur distribution est quelque peu moins restreinte que ne
1'indique Gudernatsch. On trouve souvent des depots irr£guliers sous 1'epithelium de
la fosse jugulaire, mais ils sont rares autre part. Les follicules thyroi'diens des truites
sauvages sont de forme re"guliere, g£n£ralement spheriques ou un peu allonge's, dans
les conditions types et normales ils sont composes d'e'pithe'lium ge"ne"raletnent aplati,
mais dans aucun cas plus haut que cuboi'de.
III. Une simple hyperplasie de la thyroide chez la truite existant dans des condi-
tions sauvages se rencontre assez souvent. Les follicules sont augmented en nombre,
leur forme est plus irreguliere, la substance colloi'dale est diminuee, 1'epithe'lium est
pour la plupart columnaire. La me" me hyperplasie existe aussi chez la truite d'elevage
et ne peut etre distinguee des premiers developpements du carcinome de la thyroide.
514 BULLETIN OF THE BUREAU OF FISHERIES.
La truite de mer (Salmo trutta) dans ses premieres annees presente aussi quelquefois
cette simple hyperplasie, et on trouve meme quelques adultes avec un goitre colloidal.
La gu£rison spontanee du carcinome chez le poisson ne resulte pas en goitre colloidal.
IV. On trouve generalement comme premiere evidence macroscopique de la mala-
die un foyer d'hyperhemie sur le' plancher de la bouche (plancher rouge). Le premier
signe visible de tumeur se voit generalement k la jonction des arcs branchiaux. Les
tumeurs peuvent s'etendre dans differentes directions, soit vers le plancher de la bouche,
soit de chaque cdte des oui'es. Des tumeurs independantes peuvent se developper dans
la fosse jugulaire, region qui contient souvent des depots de tissu thyroidien normal.
On trouve la premiere evidence microscopique de la maladie dans lesfollicules individuels,
generalement dans ceux proches d'un grand vaisseau. Souvent il se fait qu'on trouve
a ce degr6 un petit groupe de follicules alteres entoures par des follicules normaux.
L' epithelium est compose de hautes cellules cuboi'des ou en colonnes, le protoplasme et les
noyaux prennent un coloris profond. La substance colloi'dale est diminuee ou manque
completement, les vaisseaux du stroma sont hyperh£miques. Ceci est suivi par un
bourgeonnement de la paroi du follicule, formant de nouveaux follicules isoles, de type
irr6gulier, et aussi des projections papillaires dans les follicules. Comme la glande
n'est pas encapsulee, il se developpe un tissu de formation nouvelle entre les plans
musculaires et qui remplit aussi les espaces areolaires. A cette epoque on trouve
souvent des formes karyokinetiques, 1' epithelium est en colonnes hautes; le meme
follicules contenant souvent plusieurs couches d' epithelium. A ce moment il se peut
que la proliferation soit assez developp6e pour donner lieu k la condition reconnue
comme celle du plancher rouge. L'os, le cartilage et le muscle, tout est envahi. La
tumeur ne cherche plus le chemin de moindre resistance. Dans la periode ou la tumeur
est visible les variations dans le caractere de la proliferation sont remarquables. Tous
les differents types peuvent exister dans la meme tumeur. On peut les diviser en
alv^olaires, tubulaires et solides, ainsi que combinees avec les types papillaires et cysti-
ques. On voit souvent de petites masses ad£nomateuses d'apparence maligne envahis-
sant et infiltrant le tissu thyro'idien qui apparait moins malin aux alentours. II arrive
quelquefois qu'on trouve des ilots de tissu thyroidien normal dans les espaces et cavites
des os, tandis que le tissu environnant a ete completement remplace par le thyroi'de
carcinomateux. Une infiltration vraie de 1'os, du cartilage, de la paroi vasculaire, du
muscle et de la peau a ete demontr6e. Parfois on trouve des tumeurs qui presentent
1'apparence des soi-disant tumeurs sarco-carcinomateuses de la thyroi'de chez les mammi-
feres; un arriere-plan de cellules en fuseau ressemblant & un sarcome avec, caet la, des
alveoles. Les croissances sur la pointe de la machoire sont soit des implantations, soit
des m6tastases. Ayant trouve une tumeur de la pointe de la machoire pareille & une tu-
meur thyroi'dienne primaire, nous en avons fait une etude speciale, dont il resulte que cette
formation metastatique a probablement lieu & un point bless6. Dans un cas de tumeur
trouvee dans la paroi intestinale nous avons un cas certain de tumeur metastatique,
cette tumeur fut trouvde & 1'extremite inferieure des intestins, elle infiltrait d'un vrai
tissu carcinomateux thyroidien le tissu "muscularis mucosa" de la paroi intestinale.
Ce tissu se composait de grands follicules irrdguliers doubles d' epithelium en colonne,
CARCINOMA OF THE THYROID IN SALMONOID FISHES. 515
con tenant parfois de la substance colloi'de. II y avait des parties de la tumeur qui pr£-
sentaient 1'apparence des tumeurs primaires les moins malignes. Le caractere de cette
tumeur et la region ou on la trouva demontra sans aucun doute qu'elle £tait de carac-
tere me"tastatique. Une comparaison des differents types de thyroi'de carcinomateuse
chez les salmonidees nous demontra qu'on peut les classer approximativement sous les
trois groupes proposes par Langhans pour le carcinoma de la thyroi'de chez les mammi-
feres, c'est-a-dire struma proliferant, struma carcinomateux, et papillome malin.
V. Trois cas de la maladie ont e"te trouve"s chez les poissons sauvage aux Etats-
Unis. (i) Chez une truite de ruisseau qui peut avoir ete distribute par un e'tablisse-
ment de pisciculture; (2) chez un Laveret (Coregonus) qui ne peut £tre eleve1 ni nourri
artificiellement ; (3) chez un saumon de lac (Salmo sebago).
VI. La maladie a ete observee chez 16 especes ou hybrides des salmonidees.
La formation geologique aux sources des eaux dans lesquelles on trouve la maladie
semble n'avoir rien k faire avec son origine, de meme que le contenu dissous dans 1'eau.
La maladie est ge'ne'ralement endemique, rarement epidemique. On la trouve
dans les viviers et bassins, quelle que soit leur construction, ou les poissons sont gardes,
eleve's et nourris avec la nourriture proteidienne ordinaire de la pisciculture, c'est &
dire, foie, coeur, poumons et autres viandes crues. Elle parait avoir une tendance a
augmenter en descendant un cours d'eau. Les hybrides du saumon de la cote du
Pacifique semblent specialement susceptibles et pr6sentent un grand pourcentage de
cas. Ouand la maladie est endemique son cours est lent et chronique, avec une mor-
talite" difficile a determiner a cause de complications avec des infections secondaires ou
terminales at autres causes de mort. Le nombre des tumerus varie e'norme'ment et
augmente avec 1'age du poisson. Des tumeurs visibles macroscopiquement n'ont pas
£t€ vues dans des poissons de moins de 5 mois. Une anemie et cachexie, souvent extreme,
accompagne generalement la maladie, mais cette condition peut manquer completement.
L'immunite' se voit d'une maniere remarquable, non seulement parmi les especes, comme
chez les truites de mer (Salmo trutta) , mais aussi parmi certaines bandes contenant des
especes susceptibles. Quand des poissons affectes sont deplaces, soit dans un autre
vivier non infect e ou mis dans des conditions sauvages, un mouvement retrograde et
meme une guerison a lieu assez souvent.
VII. Des truites de ruisseau, quoique ayant etc1 nourries pendant plusieurs mois de
tumeurs de poisson et meme de cancer humain, n'ont presente aucune evidence de
maladie qu'on ait pu attribuer & cette nourriture. De m£me, des truites susceptibles
quoiqu'ayant ete gardees dans de 1'eau stagnante contenant de la matiere de tumeur
de truite, ou avec des poissons infectes dans de 1'eau circulant non renouvelee, ont,
elles aussi, donne un re'sultat n£gatif. La tumeur de poisson n'a pas encore e"te" trans-
plantee avec succes, quoique des greffes ont un peu grandi et n'etaient pas encore necro-
tiques au bout du troisieme mois. L'extrait de la tumeur est tres toxique quand on
1'injecte dans la region thyroidienne ou autre part. Des truites de ruisseau venues
d'endroits non habitus et enfermees dans des viviers de ciment et nourries avec du coeur
et du foie crus ont developpe la maladie de maniere & ce qu'elle fut visible microscopi-
quement au bout de la premiere annee et un carcinome visible macroscopiquement
51 6 BULLETIN OF THE BUREAU OF FISHERIES.
entre la premiere et deuxieme ann6e. La cuisson de la nourriture retarde la marche
de la maladie. Une retrogradation spontanee semble avoir lieu dans un grand pour-
centage des poissons ainsi nourris au bout de la deuxieme anne"e. Des truites semblables
nourries avec du poisson de mer, avec de la nourriture vegetale ou avec une combinaison
de moules et d'asticots vivants, retiennent leurs thyroi'des normaux.
VIII. Les sels de n'importe lequel des elements suivants: iode, mercure ou arsenic
dissous dans 1'eau habitue par les poissons, interrompt le progres de la maladie et ramene
1'e'pithe'lium thyroidien a une condition pour ainsi dire normale. Le resultat se produit
d'une maniere visible au bout de quelques jours. Ce traitement agit sur les tumeurs
visibles de maniere que leur grosseur peut £tre vite diminu6e. L'iode et le mercure
agissent meme quand ils sont dilues dans des millions de parties d'eau. L'iode est
effectif quand on 1'introduit dans le systeme digestif aussi bien que dans 1'eau. Des.
r£sultats negatifs furent obtenus avec 1' administration du thymol des deux manieres.
IX. L'administration, & des chiens, de la boue et de 1'eau des viviers ou le carci-
nome £tait endemique, montra d'une maniere suggestive que la boue et 1'eau contenaient
un agent capable de produire des changements bien marque's dans la thyroi'de. Des
raclures d'interieur de vieux bassins a poisson dans lesquelles le carcinome de poisson a
6t6 continuellement reproduit donnerent des r6sultats positifs. Pendant six mois on
donna & boire & quatre chiens de 1'eau dans laquelle ces raclures avaient €t€ mac6r£es.
Tous deVelopperent une hyperplasie thyroi'dienne marque'e et trois d'entre eux des
thyroi'des grossis. Les thyroi'des de trois autres animaux de controle a qui on donna
la meme eau, mais bouillie, resterent de grandeur normale. Deux d'entre eux £taient
normaux comme structure, tandis que le troisieme montrait quelques traces d'hyper-
plasie probablement caus£es par une experience ante"rieure.
Des rats qui avaient €t& nourris avec la boue et 1'eau prises des viviers ou il y avait
le carcinome et qui avaient £t£ transported une journ£e entiere en chemin de fer, don-
nerent un resultat n£gatif. Tandis que d'autres auxquels fut donnde de 1'eau avec
raclures de bassins k poisson ^galement transported, produisirent des rdsultats semblables
a ceux trouves chez les chiens, mais & un degr£ moins marque.
X. Dans les thyroi'des hyperplastiques des quatre chiens dont trois e"taient jeunes,
auxquels fut donnee la boue et 1'eau de vivier ou de 1'eau contenant des raclures de
bassins, on a trouve des vers n£matoi'des miniscules directement sous la capsule ou dans
la substance du thyroi'de. Les vers £taient entoure's de tubercules de tissu conjonctif.
Dans deux cas seulement des restes de vers nematoi'des furent trouvds dana la region
thyroi'dienne de quelques truites, dans ces cas le carcinome etait en etat de r£trograda-
tion. Si ces vers ont une signification etiologique, ce ne peut etre que simplement comme
porteurs de 1'agent causatif.
CONCLUSIONS.
1. La maladie connue sous les noms de maladie des branchies, tumeur thyroi'dienne,
goitre endemique ou carcinome de la thyroi'de chez les salmonidees, est une tumeur
maligne.
2. La maladie se presente chez les poissons vivant en liberte dans des regions
peuple'es.
CARCINOMA OP THE THYROID IN SAUMONOID FISHES. 517
3. Quand elle s'introduit dans un £tablissement de pisciculture elle devient ende-
mique et meme quelquefois e"pidemique.
4. Des poissons normaux pris loin des habitations peuvent contracter la maladie
quand on les place dans un vivier ou elle est endemique.
5. Le nourrissage avec des produits animaux proteidiens non cults accelere le
developpement, tandis que les memes produits cuits retardent sa production. Mais le
nourrissage seul n'est pas une cause efficace. II faut le combiner avec un agent transmis
probablement par la nourriture ou 1'eau, ou peut-etre par les deux.
6. En raclant la surface interieure des bassins en bois dans lesquels la maladie est
endemique, on peut acquerir un agent qui, par son action sur la thyroide des mammif eres
quand on 1'administre dans 1'eau potable, est tres probablement la cause de la maladie
chez les poissons gardes dans ces bassins.
7. On peut detruire 1'agent en le bouillant.
8. L'etat des poissons, dans n'importe quel degre" de la maladie, est ameliore favo-
rablement par 1'addition a 1'eau, de mercure, d'iode, ou d'arsenic en quantite n6cessaire.
9. L'effet du mercure, de 1'arsenic et de 1'iode sur le carcinome de la thyroide chez
les poissons, et subsequemment les resultats positifs de cet usage de metaux dans le
cancer des mammiferes, font croire & une relation th£rapeutique entre les metaux et le
carcinome.
10. Certaines especes de salmonidees off rent une resistance naturelle presque com-
plete a la maladie.
1 1 . Certains groupes de poissons d'especes susceptibles montrent un degr6 d'immu-
nite" tres eleve centre la maladie.
12. Une guerison spontanee a lieu dans un pourcentage considerable de sujets.
13. Quand on change les sujets du local ou la maladie est endemique a des condi-
tions naturelles, ou quand on leur donne une nourriture plus naturelle, on remarque
egalement une augmentation du pourcentage des gue'risons spontanees.
14. La gu£rison spontan£e semble accorder un certain degr£ d'immunite' centre la
r£cidive.
15. Le pourcentage des guerisons spontan^es semble etre plus grand dans les pre-
miers degr£s de la maladie que plus tard.
1 6. La susceptibilite a la maladie semble augmenter avec 1'age du poisson au moins
jusqu'k 1'age de cinq ans.
17. Au bout de cinq mois on a remarque un developpement thyroide et autres
changements qui presentent un tableau type de goitre parenchymateux diffus chez les
mammiferes auxquels on a donn6 a boire de 1'eau dans laquelle avaient etc suspendues
des raclures de bassins dans lesquelles la maladie e"tait endemique. Les animaux
employes comme contr61e qui recevaient la meme eau bouillie n'ont pas developp£ de
changements thyroi'diens. Que ces developpements et changements sont les premiers
degres chez les mammiferes de la meme maladie qui a lieu chez les poissons habitant les
bassins d'ou les raclures ont ete prises, voilk une deduction que nous croyons que des
experiences plus etendues justifieront.
518 BULLETIN OF THE BUREAU OF FISHERIES.
1 8. La maladie est endemique dans un grand pourcentage des £tablissements de
pisciculture aux Etats-Unis.
19. Que la maladie se presente chez le poisson sauvage, qu'on peut 1'introduire dans
des e'tablissements de pisciculture, qu'elle se localise dans certains bassins ou cours
d'eau, la maniere dont elle se repand, sa transmission aux mammiferes, le bon r£sultat
obtenu dans le traitement de la maladie avec les trois germicides inorganiques bien
connus, la destruction de 1'agent par la chaleur, le ph£nomene de la gu6rison spontanee
et de rimmunit£, tout semble indiquer que 1'agent provocateur de la maladie est un
organisme vivant.
20. Jusqu'a present rien n'indique que la maladie peut etre transmise directement
d'individu a individu.
21. Dans beaucoup de ses phases la maladie est identique avec le goitre endemique.
Comme il ne semble pas y avoir de point de demarcation entre le goitre endemique et ce
que nous croyons avoir demontre" etre un cancer de la thyroi'de, il nous semble que nous
pouvons dire que le goitre endemique et le carcinome chez les salmonidees sont la meme
maladie.
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1903. Ueber einige bemerkenswerte Tumorbildungen aus der Tierpatho logic, insbesondere fiber
gutartige und krebsige Neubildungen bei Kaltbliitern. Berliner klinische Wochenschrift,
nr. 23-25. Abstract in Journal American Medical Association, Aug. 8, 1903, p. 401.
CARCINOMA OF THE THYROID IN SALMONOID FISHES. 523
PI.BHN, MARIANNE.
1902. BSsartiger Kropf (Adeno-Carcinom der Thyreoidea) bei Salmoniden. Allgemeine Fischerei-
Zeitung, Munchen, Apr. i, 1902, nr. 7, p. 117-118.
1906. Ueber Geschwiilste bei Kaltblutern. Zeitschrift fur Krebsforschung, Berlin, bd. 4, p. 525.
1909. Fische als Uebertrager der Krebskrankheit. Allgemeine Fischerei-Zeitung, i. Juli, 1909,
nr. 13, p. 290-292.
1910. Ueber Geschwiilste bei niederen Wirbeltieren. Travaux de la deuxieme Conference Inter-
nationale pour 1'Etude du Cancer, Paris, p. 221. Discussion, p. 787.
1912. Ueber Geschwiilste bei Kaltblutern. Wiener klinischen Wochenschrift, xxv. jahrg., nr. 19,
p. 691.
DE QUERVAJN, F.
1904. Die akute, nicht eiterige Thyreoiditis und die Beteiligung der Schildriise an akuten Intoxi-
kationen und Infektionen iiberhaupt. Mitteilungen aus den Grenzgebieten. u. sup.-bd.
REGAUD, C.
1907. Helrainthiase extra-intestinal et neoplasmes malins chez le rat. Comptes rendus des
Seances et Memoires de la Societe de Biologic, t. i, p. 194.
REPIN, CH.
1911. Goitre experimental. Comptes rendus hebdomadaires des Seances et Memoires de la Soci6t6
de Biologic, t. 2, 1911, p. 225-227.
Rous, PEYTON.
1910. A sarcoma of the fowl transmissible by an agent separable from the tumor cells. Journal
of Experimental Medicine, vol. xm, p. 397.
Rous, PEYTON, MURPHY, JAMES B., AND TYTLER, W. H.
1912. A filterable agent the cause of a second chicken tumor, an osteochondrosarcoma. Journal
American Medical Association, vol. ux, no. 20, p. 1793.
Rous, PEYTON, AND LANGE, LINDA.
1913. A hitherto undescribed transplantable tumor of the fowl. American Association of Patholo-
gists and Bacteriologists, i3th annual meeting. In press, Journal of Experimental Medi-
cine.
SCHONE, GEORG.
1910. Versuche tiber die Beeinflussung der Wundheilung und des Geschwulstwachstums durch
Stoffwechselstorungen und Vergiftungen. Archiv fur klinische Chirurgie, bd. 93, heft 2,
p. 369.
Scorr.
1891. Note on the occurrence of cancer in fish. Transactions and proceedings of the New Zealand
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SEURAT, L. G.
1912. Sur la quatrieme mue des nematodes parasites. Comptes rendus hebdomadaires des S6ance<5
et Memoires de la Societe de Biologic, t. 2, 1912, p. 279-281.
SIMON, J.
1844. On the comparative anatomy of the thyroid gland. Philosophical Transactions of the Royal
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SIMPSON, B. T.
1913. Growth centers of the benign blastomata with especial reference to thyroid and prostatic
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Si, YE, MAUD.
1913. The incidence and inheritability of cancer in mice. Meeting of American Association for
Cancer Research, May 5, 1913. Zeitschrift fur Krebsforschung, vol. 13, p. 500, 1913.
SMITH, H. M.
1909. Case of epidemic carcinoma of thyroid in fishes. Washington Medical Annals, vol. 8, no. 5,
P-3I3-
SZECSI, STEPHAN.
1912. Ueber die Wirkung von Cholinsalzen auf das Blut und iiber die Beeinflussung von Mause-
tumoren durch kolloidale Metalle. Medizinische Klinik, nr. 28, p. 1162.
524 BULLETIN OF THE BUREAU OF FISHERIES.
THOMPSON, F. D.
1911. The thyroid and parathyroid glands throughout vertebrates, with observations on some other
closely related structures. Philosophical Transactions of the Royal Society of London,
series B, vol. 201, p. 91.
TYZZER, E. E.
1907. A study of heredity in relation to the development of tumors in mice. Journal of Medical
Research, vol. 17 (n. s., vol. 12), p. 199.
VIRCHOW, RUDOLP.
1863. Die krankhaften Geschwulste, bd. in. 496 p.
WILMS, M.
1910. Experimentelle Erzeugung und Ursache des Kropfes. Deutsche medizinische Wochen-
schrift, xxxvi. jg., 1910, no. 13, p. 604-606.
W6WLER, ANTON.
1883. Ueber die Entwicklung und den Bau des Kropfes. Archiv fur klinische Chirurgie, bd.
xxix, 1883, heft 3, p. 754-366, 10 pi.
BULL. U. S. B. F. 1912.
PLATE LVI.
Fie;. 1. — From Scott's "Cancer in Fish." 1891. Floor of mouth of Sa/mo fontinal is, showing protrusion of tumor in
pharyngeal floor.
FIG. 2. — Drawing from microscopic section showing acini with infiltration of surrounding structure of individual
cells. After Scott.
BULL. U. S. B. F. 1912.
PLATE LVII.
FIG. 3. — Rainbow trout. Redrawn from Gilruth's colored original, 1902. Large tumor on each side of branchial
junction. Gill fringe distended on surface of lower one.
FIG. 4a. — Yearling hybrid salmon. Massive tumors and marked emaciation. I<ot 19SSa.
P'IG. 4b. — Two year old Sahno sebaso, extreme emaciation. I¥ot 1950.
FIG. 4. — Salnio foittinafis 2 years old. First external evidence of tumor in base of muscular structure of isthmus,
showing marked infiltrative tendency of growth.
BULL. U. S. B. F. 1912.
PLATE LVIII.
II
11
FIG. 5. — Redrawn from Maurer, 1886. Thyroid of n trout 20 cm. long; shown in its relation to the branchial arteries,
seen from the ventral side.
FIG. 6. — Redrawn from Maurer. Median section to show distribution of thyroid about the ventral aorta in a trout 2.5
cm. long.
FIG. 7. — Redrawn from Maurer. Cross section of the head of a trout embryo of 30 days, showing earliest evagination
of pharyngeal epithelium to form the thyroid.
FIG. 8. — Redrawn from Maurer. Median section through head of trout embryo of 35 days. Primary thyroid vesicle
(/) still attached to parent epithelium by pedicle.
FIG. 9. — Redrawn from Maurer. Cross section of a trout embryo of 35 days. Primary thyroid vesicle (/) separated from
parent epithelium.
FIG. 10. — Redrawn from Maurer. Median section through head of trout embryo of 41 days. Compared witli figure 8, it
shows that the elongated primary thyroid vesicle (/) has moved backward and now lies ventral to the aorta.
FIG. 11. — Drawing showing gross appearance of jugular pit from below.
BULL. U. S. B. F. 1912.
PLATE LIX.
FIG. 12. — Salvelinus fontinalis in sac stage, hatched a few days; showing: relation of thyroid follicles to invagination
which becomes jugular pit. X86.
Fi<;. 13. — Brook trout fry showing early thyroid follicles containing colloid material. XS6.
BULL. U. S. B. F. 1912.
PLATE LX.
FIG. 14. — Scotch sea trout. Longitudinal section of lower jaw above showing normal thyroid follicles; below, in
the right hand comer, an isolated misplaced thyroid follicle lying adjacent to the epithelium of the pit.
BULL. U. S. B. F. 1912.
PLATE LXI.
GILL FILAMENTS OF 4TH ARCH
HEAD OF KIDNEY
ESOPHAGUS
OPBRCULUM
PREOPERCULUM
CHEEK MUSCLE IN SECTION
ORAL MEMBRANE
4TH BRANCHIAL ARCH
....3RD BRANCHIAL ARCH
2ND BRANCHIAL ARCH
ST BRANCHIAL ARCH
HVOID CORNi:
FIG. 15. — Composite picture of lateral and longitudinal distribution of normal thyroid in the Salmon idsie, with vessels.
1ST COPULA (CARTILAGE)
1ST BASI BRANCHIAL
2ND BASIBRANCHIAL
ORAL MEMBRANE
TEETH OF TONGUE
BASIHYAL
TONGUE c RTIL'AGE
H OH'YAL
MUSCLE
2ND COPULA (CARTILAGE)
4TH BASIBRANCHIAL
3RD BASIBRANCHIAL
3RD COPULA (CARTILAGE)
: " -|--. VENOUS SINUS
; . .{-MUSCLE
ESOPHAGEAL MUCOSA
AND:AREOLAR TISSUE
HYPOHYAI, SYMPHYSIS
MUSCLE
AURICLE
BULBUS AORTAE
.VENTRICLE
.'EPITHELIUM
SUBMUCOSA
SYMPHYSIS OF CLAVICLE— CORACOID PAIRS
VENTRAL AORTA
UROHYAL
BRANCHIAL SPACE
FIG. 16. — longitudinal and dorso-ventrnl distribution of thyroid in the SalmoimUe.
BULL. U. S. B. F. 1912.
PLATE LXII.
:,'
B^§.-'''v X-^v "•;. --W
•KWL-:"1! .** — *" «liSiife*i%^ -' W
Fio. 17. — Wild brook trout from An Sable River; 8.2 cm. lonsr; cross section showing distribution of normal thyroid. X86.
-'.
»
r^-vC"V •"•
.^* «:- ?V-*U
/^ v! -OK-5^— ^ r^i
£
=s?<^ *• , '1'flF1 ""c?':-.. Gr-/
'*&*&&&
•K.9^W
k~ s*5?«*s**e' af^^fe* -?
>%«c •;£-•* - <-*8E--**$&'
<%«^: %^^'^^^SS
l^y ^f^ii ., ••-<'.?
;5^->' f .' ^
Fie. 18. — Algonquin wild brook trout; simple hyperplasia; high cuboidal epithelium reduction in some follicles and
absence in others of colloid. Distinct hyperaemia about follicles; increased amount of thyroid. X86.
BULL. U. S. B. F. 1912.
PLATE LXIII.
Fui. 19. — Domesticated Scotch sea trout fingrerling-; normal thyroid structure. X86.
^V« &l
m ;
. . . -
" j.V
KIG. 20. — Dotnesticated Scotch sea trout fmgrerliiiK: same hatchery as above, showing simple hyperplasia, increased
number of thyroid follicles; epithelium high cuboidal and low columnar; colloid diminished. X86.
BULL. U. S. B. F. 1912.
PLATE LXIV.
£te
.- '
Kit;. 21. — Adult domesticated sea trout, normal thyroid structure. X86.
Kit;. 22. — Adult domesticated Scotch sea trout; colloid goiter. X86.
BULL. U. S. B. F. 1912.
PLATE LXV.
FIG. 25. — Brook trout, showing- rectal metastasis of thyroid origin (Anal fin pinned back to show tumor.)
FIG. 24. — Brook trout, showing: large
round tumor springing' from the jugular pit.
FIG. 23a. — A view of normal floor of
mouth of adult brook trout.
FIG. 23 — Hyperemia of floor of mouth of adult brook trout,
so-called red floor. First macroscopic evidence of hyperplasia or
carcinoma of thyroid.
BULL. U. S. B. F. 1912.
PLATE LXVI.
FIG. 26. — Brook trout, showing massive thyroid tumor in the mouth cavity, springing froiit the floor of the mouth.
FIG. 27. — Two year old brook trout, showing massive tumor filling the entire gill space.
FIG. 28. — Brook trout, showing tumor mass at the tip of the lower jaw.
BULL. U. S. B. F. 1912.
PLATE LXVII.
FIG. 29.— Brook trout showing noclular growths in FIG. 30.— Brook trout showing numerous tumor vege-
floor of mouth. tations in floor of mouth.
FIG. 31. — Section of floor of mouth showing thyroid follicles growing in epithelium above basal membrane. X70.
i«*l«?"^L.r "JOf*' L' f»&^ **& :
FIG. 32. — Section from floor of mouth showing histological structure of papillary growths fouiul in floor of mouth
illustrated macroscopically by figure 3D. X94.
BULL. U. S. B. F. 1912.
PLATE LXVII.
FIG. 29. — Brook trout showing nodular growths in FIG. 30. — Brook trout showing numerous tumor vege-
floor of mouth. tations in floor of mouth.
FIG. 31. — .Section of floor of mouth showing thyroid follicles growing in epithelium above basal membrane. X70.
'* % ri •', ' •* "jfttffjT'^Tn' J1 r*' ' I ' "<4e!'t^>^*la»' &&***'• " ' «
:^
FIG. 32. — Section from floor of mouth showing histological structure of papillary growths found in floor of mouth
illustrated macroscopically by figure 30. X94.
BUU,. U. S. B. F. 1912.
PLATE LXVIII.
FIG. 33. — Infiltration of aortic wall by alveolar carcinoma FIG. 35. — Same section, higher power. Tubular struc-
of thyroid. ture with mitoses.
^r f
9 i> *» m *« J* " c^1- a *• ? * i» * '*
1 art^f^L n
# ^*
Vic,. 34. — Dniwinjr showing infiltration of surrounding .structures in the early stage of carcinoma of thyroid.
BULL. U. S. B. F. 1912.
PLATE LXIX.
FIG. 36. — High power section of the early stages of the disease showing formation of new follicles by budding of the
alveoli with subsequent splitting off. Note karyokinetic figures. X200.
FIG. 37. — Cross section of the lower jaw showing growth infiltrating the surrounding structures.
PLATE LXX
$Jrtt9&*S*£%fyi
ra:-*
mSKfsffSsssK^^^VwS^
FIG. 38. — Section showing the mixed type. In the center a few follicles containing colloid with background of spindle
cells. X280.
am <jm*i 'mn*y fr . ,•« ._.~* , -tifvi^mmm. ** \.j~.-vr' *-
.
' • *
' •
3fc
* N ' m~ UI^BR
js. ^ •.<•-.„
«* o* \S • ' •?*' *••*
3* \WA v. ..i'.,»Wt
FIG. 39. — Section of tumor presenting the picture of proliferating stntina of l,anghans. showing numerous karyokin-
etic figures. X600.
BULL. U. S. B. F. 1912.
PLATE LXXI.
FIG. 40. — Section of lower jaw showing nodular development in various portions of the tumor mass. X10.
BULL. U. S. B. F. 1912.
PLATE LXXII.
, /
Fir,. 41. — High power section from figure 39 of a nodule showing closely packed spindle and oval cells with deeply
staining, nuclei, with here and there an attempt at alveolar arrangement. X94.
•S 'fi
&,.•>••'
m^^M
Fu;. 42. — High power section from figure 39 showing a small, distinct nodule of adenomatous type lying: in loose
alveolar structiire. X94.
Buix. U. S. B. F. 1912.
PLATE LXXIII.
w&arasfe
*iw<\ifjr "^ ;%, y • i StfSrf^B •¥ i$
*fc*fc»» iw^^&^aiS^UJ&V
fe^S^S?^^^
•»>-• . f x'***>»»>5v: »**«&,*?>>>• i
S^|4'!S^T%f^
ll "S«^
X-~ tJL ••'* *«• V> ',
&.^wte&Js4
sS^aww^^w'l ^
JKiw?-Y'i^W
r^t^^w^
***<•
e*
pIG 43 — section showing intensive nodular growth FIG. 44. — Section showing individual follicles of more
with concentric compression of the surrounding tumor malignant type infiltrating surrounding tumor tissue,
tissue. X40. X130.
i** rrr1"" • VHY '^^*y«''<^* - &23J3&
^^>
» •• • • « -
FIG. 45. — Section showing encapsulated nodule of papillar type lying in tumor tissue of alveolar type. X94.
BULL. U. S. B. F. 1912.
PLATE LXXIV.
r'lHj
KIG. 46. — Section of floor of the mouth showing tumor cells infiltrating and destroying basal membrane. Splitting
of elastica. X260.
Km. 47. — Drawing of section showing normal thyroid tissue isolated in a bone space surrounded by tumor tissue.
BULL. U. S. B. F. 1912.
PLATE LXXV.
Fi«.48. — Section showing infiltration and destruction of cartilage. X136.
if v /i * r. r1 i
•• • '/*&$$
•J$m&>
^^ j$- <&<*•''*
FIG. 49. — Section showing involvement and destruction of bone. Xl^
BULL. U. S. B. F. 1912.
PLATE LXXVI.
pIG 50. — Section showing involvement of aortic wall. Tumor alveoli between elastic lamellae of media. X260.
FIG. 51. — Section "showing- infiltration of individual muscle fibres. Cells within the sarcolemma. X500.
BULL. U. S. B. F. 1912.
PLATE LXXVII.
1 V -vT*. Jt* « - r J »•*• TA
^^1^
iy&syQ
Fio.52. — Primary tumor of thyroid region. Alveolar type. X136.
FIG. 53. — Section of metastasis on the tip of the jaw; from the primary tumor shown in figure 52. X136.
BULL. U. S. B. F. 1912.
PLATE LXXVIII.
FIG. 54. — Photograph of metastatic tumor in the rectal wall
Normal size.
FIG. 55. — Microscopic section of re
mucosa over surface of tumor. X86.
sis showing attachment to the intestinal wa
FIG. 56. — Section of rectal metastasis showing tendency to the formation of papillar nodules. X86.
BULL. U. S. B. F. 1912.
PLATE LXXIX
^v
J^^^Bre-^tty* \\ J*:**44* Jr-
Hi(;,57. — High power section of rectal metastasis showing infiltration of the muscularis mucosa. X160.
fe^^r^aii
FIG. 58. — Section showing peculiar type of fish thyroid tumor which may be compared with plate 2, figure 6, of
Laiighans' article on malignant disease in the human thyroid. X160.
BULL. U. S. B. F. 1912.
PLATE LXXX.
FIG. 59. — Section of fish thyroid tumor resembling the proliferating struma of I,anghans as illustrated in plate 2,
figure 12, of his article. X160.
FIG. 60. — Section of proliferating struma in man; original case of Langhans to be compared with figure 58. X160.
BULL. U. S. B. F. 1912.
PLATE LXXXI.
FIG. 61. — Papillar type in fish thyroid tumor resembling malignant papillar type in man, as illustrated in I<anghans'
article, plate 7, figure 32. X160.
Fir,. 62. — Section o
figure 60. X160.
•„ T %M«PE *r w *
original case; to be compared with
BULL. U. S. B. F. 1912.
PLATE LXXXII.
FIG. 63. — Fish thyroid tumor showing tubular type resembling- the struma of Geisslar, as illustrated in plate 6,
figure 27 of L,anghans' article. X160.
•fai fefV^:
FIG. 64. — Section of fish thyroid tumor. Solid type. From five-months-old domesticated brook tro
BULL. U. S. B. F. 1912.
PLATE LXXXIII.
Kir;. 65. — Section of fish tumor closely resembling the so-called struma nodosa, with "Wachstum centrum" of
Aschoff. X160.
FIG. 66. — Section of struma nodosa from a human thyroid gland ; to be compared with figure 64. X160.
BULL. U. S. B. F. 1912.
PLATE LXXXIV.
FIG. 67. — Infiltrating thyroid tumors in the gill region of a wild white fish (Coregonus c/ufaeiforniis.)
:«S* 2»
m -$*>
.1^- T«A1
8 ''**• * ' ;<r «' /''^ *^2i
l^i^iiei.ySHw
§
FIG. 68. — Microscopic section of the tumor shown in figure 66. Infiltration of wall of vein. Cell nests in lumen. X136.
BULL. U. S. B. F. 1912.
PLATE LXXXV
i<;. 69.— Photograph showing tumor in a wild brook
PIG. 70. — Low power photomicrograph of the tumor of
trout \SalveHnusfontinalis. )
figure 68. Note the large nodule within the tumor mass.
^ °
N°te the Spindle Cel1 character of the tl"»or
BULL. U. S. B. F. 1912.
PLATE LXXXVI.
*
KIG. 72. — Massive thyroid tumors in wild Satnw sebago 4 years old, caught in Sebago I,ake. Maine. Largest fish
observed with tumors. Natural size.
>
FIG. 73. — Smallest tumor fish, domesticated brook trout 5 months old. Natural size.
BULL. U. S. B. F. 1912.
PLATE LXXXVII.
FIG. 74. — Photograph of longitudinal section of lower jaw of landlocked salmon; illustrated by figure 72.
t
FIG. 75. — Section showing alveolar type of tumor. Wild landlocked salmon. Illustrated by figure 71. X160.
BULL. U. S. B. F. 1912.
PLATE XC.
BULL. U. S. B. F. 1912.
PLATE XCI.
FIG. 84. — Section of wild Wisconsin brook trout. Raw liver feeding- 12 months. Focal development carcinoma of the
thyroid. Small group of follicles with columnar epithelium. Reduced colloid. Hyperaemia about follicles. At periphery
normal unaltered thyroid follicles. XS6.
FIG. 85. — Wild Wisconsin brook trout. Raw heart feeding 12 months. Beginning carcinoma of the thyroid. XS6.
BULL. U. S. B. F. 1912.
PLATE XCII.
*r~
••
^.
' '
,.
J- "
Fi«. 86.— Section of wild Wisconsin brook trout from same experiment. Natural food 12 months. Normal thyroid. X86.
A
£P;/-J
'Svatt
,C^''' •
IIP'
w
-
"• JP ' • » ' -
f; X \ »/j -
' ^ ' '• "'• /
'r* • t" ' j&**—f . '
f • / "T3fc-i.'.
?Sr
,
iaiFi/
• •-•<^rr
:^>>:f "<v;^-
%%^/1 ' "K^-tO r/%^-'- :- •
>-:'i::\--*v-
m
*-,
/
:^
s^Sl
:.87. — Section of wild Wisconsin brook trout. Cooked liver feeding 12 months. Normal thyroid.
BULL. U. S. B. F. 1912.
PLATE XCIII.
- .. , *-***•
»
Km. 88. — Wild Wisconsin brook tront. Fed marine fish 12 months. Normal thyroid. X86.
\ >
. jCfr .- : <t-W-^
-^K ^
"" >»•
KiG.89. — Wild Wisconsin brook trout. Vegetable food 12 months. Normal thyroid. X86.
BULL. U. S. B. F. 1912.
PLATE XCIV.
.1 V
\ V! <\
v^
FIG. 90. — Low power section at median line through thyroid region of wild Wisconsin brook trout, showing well-
developed carcinoma of the thyroid infiltrating surrounding structures, bone and cartilage. After 18 months raw liver
feeding at Craig Brook. Experimental induction of carcinoma of the thyroid. X13.
PLATE XCV.
BULL. U. S. B. F. 1912.
FIG. 91. — Section of thyroid showing spontaneous recovery from carcinoma of the thyroid. Early stage. Wild
Wisconsin brook trout. Fish No. 2099 A. X86.
FIG. 92. — Section showing spontaneous recovery from experimentally induced carcinoma of the thyroid in wild
Wisconsin brook trout. Fish No. 2099 B. X86.
BULL. U. S. B. F. 1912
' ..
PLATE XCVI.
FIG.
and heart
93. — Section thyroid region domesticated yearling, Cold Spring Harbor hatchery, kept in old troughs. Raw liver
feeding. Well developed hyperplasia. X86.
ft* ~^V $f$ jJH& ^~***~~ ' -~-~* <-->^****^S — -^v _ ^.,. -a*^^*^^^^ * '" *
mft^~ *• "Virs* -' " "
FIG. 94. — Yearling domesticated brook trout. Cold Spring Harbor hatchery. Same lot of fish as figure 93. Kept in
water of Church Spring. Raw liver and heart feeding. Normal thyroid. X86.
BULL. U. S. B. F. 1912.
PLATE XCVII.
FIG. 96. — Marked hyperplasia domesticated brook trout used as control for figure 97. Fish 1040, table ix. X86.
FIG. 97. — Fish from same lot treated by adding in continuous concentration potassium iodide in the water 1 : 5,000.000.
Marked regression of hyperplasia at the end of 13 days. Fish 1039, table ix. X86.
PLATE XCVIII.
BULL. U. S. B. F. 1912.
FIG. 98. — Marked hyperplasia domesticated brook trout used as control for figure 99. Fish 1070, table ix. X86.
FIG. 99. — 'Fish from same lot treated by addinsr in continuous concentration potassium iodide in the water 1 : 5, 000. 000.
Marked regression of hyperplasia at the end of 27 days. Fish 1069, table ix. X86,
BULL. U. S. B. F. 1912.
PLATE XCIX.
FIG 100— Hybrid yearling salmon. I,arge protruding tumor showing marked change with reversion toward normal
type as the result of treatment with iodine added to the water by continuous flow in the proportion of 1 : 5,000,000
days. Great visible reduction in size of tumor. Fish 1083. table ix. X86.
FIG. 101. — Section through tumor retrograding as the result of treatment with potassium iodide added to the water
by continuous flow in a concentration of 1 : 5.000,000, at the end of 31 days. Large area showing organization by connectiv
tissue, previous hemorrhage in substance of tumor induced by treatment. Great reduction in size of tumor. I
table ix. X136.
BULL. U. S. B. F. 1912.
PLATE C.
*~
FIG. 102.— Control for figure 103. Fish 1090. table xn. XS6.
FIG. 103. — Domesticated brook trout from the same lot as figure 102. treated with bichloride of mercury added by
continuous flow to the water in the proportion of 1 : 5.000.000 for 12 days. Disappearance of hyperplasia. Marked reversion
to the normal type. Fish 1089. table xn. XS6.
BULL. U. S. B. F. 1912.
PLATE CI.
-
~t..
i
FIG. 104. — Control for figure 105. Fish 1085. table xn.
^/^••1^P"»-/
Ijfc 1
"f YK-* ! f
WSL/
S***fis < /
wwm *<••*«•'•,
vasr r^5j
U
'«»,?Hte^ ' *•
^ *»i )" <>
v 3^' r ^ '*% »A I ' "~""^^*.--
i-w)(Mii 1OT
TfD^'-Vi
.c5vi^^-/
p
L43^N!
$
, v •
V
<ra *
JU-5? o
v. \ V W
mKff
, m W^-'|/
|^
&r,
jiA. /
asSMT!/ ? I
!H$IJ/ /
KIG. 105. — Domesticated brook trout from the same lot as fisrure 104. treated with bichloride of mercury added by
continuous flow to the water in the proportion of 1 : 5,000.000 for 14 days. Disappearance of hyperplasia. Marked
to the normal type. Fish 1084. table xn. X86.
BULL. U. S. B. F. 1912.
PLATE CII.
v
mgk^.
FIG. 107. — Section through margin of large tumor retrograded under treatment with bichloride of mercury 1 : 5.000,000
added to the water for 18 days. Marked atrophy of tumor cells, remnants of nests of cells in marginal connective tissue
presenting a picture similar to regression of carcinoma in mammals. Fish 1065, table xn. X86.
BULL U. S. B. F. 1912.
PLATE CIII.
,.-1(- ion— Section through tumor of two-year old brook trout treated with bichloride of mercury added by continuous
flow to the water in proportion of 1:5.000.000. Result at the end of 11 days. Great reduction in size of tumor. Reversic
of tumor tissue to the normal type. Fish 1144. table xn. X86.
r*'
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JSP*
**&£
r., ..^,_- ,,-«'-yVt, ttptMilt'A,-
i •?«.:•.«* ."iss/ssr^^Krs^
•Jf^^p*^^ v*s .>-:•>
p,G i(j9 —Domesticated brook .rout. Visible tumor. Marked diminution in size of the tumor and ma
tumor tissue with reversion toward normal, as the result of treating for 22 days with arsenic trioxide added
flow to the water. Note marked change in epithelium. Fish 2036. table xiv. X86.
rked chanKe in
by contm
BULL. U. S. B. F. 1912.
PLATE CIV.
~v,
'- *
FIG. 110. — Section of thyroid of dog 21 used as control for dog 16, figure 111. Received same water as dog 16 but
^^P^*^**' ?*%SWr4S
FIG. 111. — Section of thyroid of dog 16. Marked enlargement of the thyroid, well developed hyperplasia as the result
of drinking water in which were suspended scrapings from fish troughs in which carcinoma of the thyroid in fish was
prevalent. X160.
BULL. U. S. B. F. 1912.
S
^wSP ^
!
[J1C CIIU UI I1VC IlUJIllIlSi 1HJII1 UIlIlJ^-lllK WtlLtl i
arcinoma of the thyroid was prevalent. The same
BULL. U. S. B. F. 1912.
s .r%
Fu;. 114. — Section of thyroid of dog 20 used as control for dogs 22. 16 and 17. Received the same water as dogs 16, 17
and 22, but. like control dog 21, boiled before drinking. X160.
*^cm&
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Fu: 115. — -Dog 22. Section of enlarged thyroid. Well developed hyperplasia after drinking water five months with
suspended scrapings from infected fish troughs. The same experiment and result as dog 16. figure 111. and dog 17,
figure 112. X160.
BULL. U. S. B. F. 1912.
PLATE CVII.
Fie;. 116. — -Section of normal thyroid of adult female dog. mother of dogrs 15. 16, 17, 20, 21 and 22, used as control for
dogr 18. figure 117. Received same water but boiled before drinking. X160.
fc ^»
>•., ^•..•'•J^|,Y
'
:;g
Fit;. 117. — Section of markedly enlarged thyroid of adult dog 18. Result after five months drinking water in which
were suspended scrapings from fish troughs in which carcinoma of the thyroid in trout was continually developing. X160.
BULL. U. S. B. F. 1912.
PLATE CVIII.
Kit;. 118. — Section near periphery of enlarged thyroid of dog 18. The process is less intensive than near the center
ns illustrated in figure 117 and 119. Columnar epithelium, marked papillary growths into distorted alveoli. Colloic
absent. X160.
BULL. U. S. B. F. 1912.
PLATE CIX.
V
X»r* Xfc.,
r »•» *? *v • > -
FIG. 120.— Normal thyroid gland of rat 32 used ns control for rat 115. figure 121. X160.
'^C
_»,\» r |J? rV jIV
Ab>*<.^! ••T»T »T*V.'J»TA »••".*• 7. »« IV*. »
f 90 days, from drinking water with suspended set
it conducted in Buffalo. X160.
•*•-* ^-»*-^ • f A ^v: r ».» »•••••
FIG. 121. — Hyperplasiaof thyroid in rat at the end of
nfected fish troughs from Craig Brook, Maine. Experitneii
BULL. U. S. B. F. 1912.
PLATE CX.
• V* . --'. •-( 'v
FIG. 122. — Section of dog's thyroid showing tubercle with FIG. 123. — Section showing head of nematode inclosed in
cross section of nemntode in capsule. X70. tubercle. X550.
__3&d&«
! f • ' -CT "'/F^t • .^»V "
v^'^Vr- ^
£.«'. f^ftaK\J
••u ..«•*•" » -•>>
•1
FIG. 124. — Cross section of nemntode in center of tubercle,
in dog's thyroid. X130.
feg«x^4Jftf3PrvV v<^ ^v
.#>. •-.*?• ,>V / N^> > ./*
^ -*J«3L^ AlHf AA!. Afc "A;.- ^ — • .
FIG. 125. — Healed tubercle showing no evidence of
nematode. X130.
L.,-
^:> vJ^Ma?
ir'' ^^ilfe^
•f ' M- ^1* ^'^ ," ,^» ^~ *_?*•* lr ^« *«* "*• . * *- * . r *\
:TT » •-«.»•.'>«•'' ^~ »*• »*_**'*^ _^^^M^^^ * • ,
FIG. 126. — Section of tubercle in fish showing spaces
evidently occupied by nematode. X240.
FIG. 127. — Section showing healed tubercle in fish.
X130.
CARCINOMA OF THE THYROID IN THE SALMONOID
FISHES : : : By Harvey R. Gaylord and Millard C. Marsh
From BULLETIN OF THE BUREAU OF FISHERIES, Volume XXXII, 1912
Document No. 790 : : : : : : : : : : : : : : Issued April 22, 1914
WASHINGTON
GOVERNMENT PRINTING OFFICE
1914
UNIVERSITY OF CALIFORNIA LIBRARY
BERKELEY
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