Part 12

Beechy’s Gopher (_Citellus grammurus beecheyi_). Adult ♂ . Gradual loss of power in limbs beginning about two weeks ago. No other symptoms.

DIAGNOSIS.—Multiple myeloma. Anemia. Acute parenchymatous nephritis. Chronic ulcerative gastritis.

External Appearance.—General condition fair, hair in good condition. Fully developed animal. Muscles contained no fat.

Respiratory Tract.—Thymus, large soft gray homogeneous. Both lungs are distended, pale, homogeneous, yellow pink, boggy, do not crepitate, but contain no edema. Lymph nodes, small soft anthracotic. Pericardium contained no fluid.

Abdomen.—No adhesions. Size of liver normal or slightly small, firm and pale brown-red. Architecture irregular showing areas of perfect homogeneity and others where lobules are clear outlined by paler interstices. Gall-bladder distended, contains brown fluid. Common bile duct, patulous. Spleen, normal or slightly small, consistency soft, capsule smooth, location normal; section surface, homogeneous pale pulp, faint trabeculæ. Kidney normal in size and shape, capsule smooth, strips easily, smooth brown surface; section surface glistening, opaque; consistency firm; thickness of cortex normal and of medulla normal; homogeneous cortex, glomeruli not visible.

Adrenal.—Narrow, brown, opaque cortex; pale brown, opaque medulla. Bladder, small quantity of cloudy urine showing albumin, bile and many granular casts, few hyaline casts. Teeth carious broken; mouth pale. Stomach distended; serosa and wall pale, contained gas; mucosa pale, flat, translucent except in pyloric segment where it is slightly thickened, irregular, opaque and there are several saucer shaped depressions covered with black, shiny material; these seem like sluggish ulcers. Intestinal tract throughout seems normal save for its pallor. Few natural fecal masses in lower gut.

Skeleton and Muscles.—All bones are irregular in thickness, very brittle and show in their length irregular swellings made up of periosteal growth and probably increase in marrow. The latter is pale yellow with punctate hemorrhages. Skeleton seems too soft to give support, but there is little deformity.

Microscopy.—Bone section shows a myelomatous growth of costal marrow, new myelocytes predominating. The cells are packed in disorderly fashion through the marrow. They are chiefly lightly granular but a few distinct promyelocytes are found. The hyperplasia is invading cartilaginous bone with absorption. In some places cartilage is of fetal type. Perichondrium is active but there is no round cell infiltration. Ossification is imperfect at costochondral junctions. Kidney shows granular and vacuolar degeneration of epithelium with flattening of tubular lining. Nuclei are for most part normal. Epithelium of tufts and Bowman’s capsule is likewise granular and vacuolated. Distal and discharging tubules seem to be most affected. No well defined casts are found.

Liver.—The fine markings mentioned in the notes correspond to areas of infiltration of large pale mononuclears without granules. There is no fibroblastic or polynuclear increase around them. Very small necroses seen in hepatic lobules. Very slight increase of connective tissue is noted.

This seems to be a tumor of true myelocytic origin; none of the cells was of the plasma type as usually depicted. The second case stands in the files as a myeloma, yet the full description and slides have been mislaid. It is cited briefly for record.

Samoli Ostrich (_Struthio molybdophanes_). Adult ♂ . Would not eat for three weeks.

Diagnosis.—Tuberculosis of lung, liver, spleen, kidney, mesenteric and cervical lymph glands. Myeloma of periosteum of pelvis.

Skeleton and Muscles.—Large tumor mass lying on inside of pelvis measuring about ten inches by twelve inches with a thickness of about four inches. It is sharply defined and separated from adjacent muscle by a capsule. Inner border is directly below the peritoneum, and outer border lies directly on bony pelvis. Traced to its origin it seems to come from pelvis yet tumor peels off bone easily, leaving a rough surface. The tumor is soft and succulent, of a red gray color and contains some fat and much irregularly placed masses of bony tissue.

SECTION V DISEASES OF THE LYMPHATIC TISSUES INCLUDING SPLEEN

Since we have followed diseases of the blood from the simple anemias to a place where mononucleosis in the circulatory system and in the fixed tissues is the prominent feature, another step reaches the area whence most of these cells emanate—the lymphatic system. The anatomical and physiological position of the lymphatic circulatory apparatus is closely analogous in the classes under discussion, and it stands in an anatomico-clinical sense, closer to the hematopoietic system than to any other structures, throughout the whole animal creation. This anatomical division of the circulation is closely comparable, for pathological purposes, in the mammals whereas in the birds one finds noteworthy variations. In the class Aves lymphatic radicals are extremely numerous, the plexuses in the extremities and thorax perhaps being complemental for the rather scantily supplied blood vessels. About the fibulo-tibial and femoral muscles the tiny lymph vessels form an extraordinarily dense and intricate lacework, a replica of which may be found in muscles of the upper limb, while in the pelvis and thorax a rich plexus is distributed around both kinds of blood vessels and also lies within the walls of air sacs. The air sac walls in the chest display lymphatic lines very well in birds that have been for many years exposed to railway dust, the natural pearl gray glistening membrane looking as if black pepper had been evenly dusted over it. The lymph glands or compound nodes so easily discovered in mammals are practically absent in birds. Along the large thoracic vessels and in the pelvis of some anserine and struthious varieties, small illy defined masses of lymphatic tissue may be discovered by careful search but they do not possess nodal arrangement and capsule. Lymph follicles on the other hand, are quite numerous in the respiratory, and especially, the intestinal tract. Groups of follicles may also be found in the lining of the upper ends of these tracts in such situations that the names faucial, pharyngeal, or even tubal tonsils are justly applied. I do not find any reference to a lingual tonsil in birds, but this structure is found, with of course many modifications, down as far as the monotremes. The lymphoid tissue of the nasopharyngeal region is so placed in animals as to be exposed to aerial and food infections, just as it is in man. It is, however, noteworthy that chronic inflammations leading to hypertrophy or to obstruction have not come to our attention. There is only one diagnosis of chronic tonsilitis in our records, a determination based upon the nodular red-brown prominence of the tonsillar region, but there were no true hypertrophy and areas of fibrosis combined with necroses as seen in human medicine; this case concerned a Chacma baboon.

HYPERPLASIA.

In so far as the reaction to infectious or toxic agents is concerned there seems to be a fairly uniform character through the mammalian groups, but in the Aves there are a few differences worthy of mention. It is at once admitted that these observations upon birds are based upon a very few sections of isolated lymphatic tissue, but they are supported by records of the changes in nodes in mucous membranes and viscera, and by those in the spleen. The first and perhaps most noteworthy difference is in the paucity in birds of large mononuclears of the endothelial type. Their position in chords, sinuses and germinal centres is taken by deeply staining mononuclears, of the size and general character of large lymphocytes as seen in the blood. The hyperplasia in the follicles is much more dense but it is outdone by that in the chords. Since the nodal tissue of birds is not so sharply delimited by some sort of capsule, it is but natural that the hyperplasia should be diffuse; in the intestinal wall it may extend laterally twice or thrice the width of the normal follicle. Necrosis, unless the disease be mycotic, tuberculous or parasitic, is uncommon.

It may be well to discuss for a space the reaction to infection of the thoracic and intestinal lymphatics in mammals. The amount of lymphadenoid tissue in the mediastinum is very great in some mammals, notably the Ungulates, while in others, the Rodents and Primates, for example, it is not so plentiful. Nevertheless the gross and minute changes are usually of the edemato-exudative type—large, pink, soft, moist glands. In the abdomen, on the other hand, one usually finds well outlined, firm, yellow nodes in the mesentery and behind the peritoneum. This is not only to be discovered in various chronic diseases of the intestine but even in acute, so-called toxic enteritis seen in carnivores from food poisonings. One must therefore ask if the local nodes abundant in the intestinal mucosa do not take up the poisons which cause the acute hyperplasia and are in turn backed up by the stalk glands. Even in so acute and overwhelming a disease of the intestine as hog cholera (which we have not had here) the glands retain their general structure, although hemorrhagic, while in late stages they become firm, sharply outlined and pigmented. In birds there may be swelling of the omental bursæ, but as there are no lymph glands no masses are found.

The response on the part of the lymphatic tissues as a system, or some large section of this system, is shown in the following figures. It is our practice to include in the diagnosis general acute or chronic lymphadenitis or inflammation of a large drainage area. Acute changes have been mentioned 103 times, in which the important orders are represented as follows: Primates 21, Carnivora 46, Ungulata 15, Rodentia 3, Marsupialia 13, Pinnepedia 4. Chronic changes are mentioned 43 times as follows: Primates 7, Carnivora 19, Ungulata 14, Marsupialia 1, and Pinnepedia 2. This great proportion among the Carnivora does not indicate that they have more lymphatic structures for such an advantage is probably possessed by the Ungulata, but perhaps should be interpreted as an evidence for this order of the ready response to irritation on the part of the tissues in question. They probably suffer more, as we shall see later, with inflammation affecting drainage tracts. The hyperplasias or inflammations included in the figures above most often accompany gastroenteritis, pulmonary diseases or long standing infectious processes such as arthritis, while there are also lymphatic enlargements both local and general, associated with skeletal degenerations (rachitis-osteomalacia) and with thyroid disease. The former may be described as lymphadenitis, the latter as lymphatic hyperplasia.

Unlike lymphadenitis, a condition associated with some definite infectious or toxic cause, systemic hyperplasia of the lymphatic tissue may be apparently primary and causeless. In a pathological and clinical sense alike these hyperplasias are protean in their manifestation, making a satisfactory classification extremely difficult. For our purposes they are divisible into acute and chronic, associated with an increased number of circulating lymphocytes and without such a lymphocytosis.

The first, acute systemic lymphatic hyperplasia, is known in man as status thymicolymphaticus, a well recognized condition chiefly encountered in youthful males having some of the stigmata of the opposite sex. There is no record, nor have I any recollection of a pathological state in a wild animal comparable to this condition.

If acute generalized lymph node increase be associated with lymphocytosis, acute lymphatic leucemia exists; there is no case in our records. Chronic enlargement of lymph nodes with increase of circulating mononuclears is chronic lymphatic leucemia; a case of this has been cited under leucemia.

LYMPHOMATOSIS.

Chronic enlargements of the lymphatic tissues without leucemic blood present a bewildering number of varieties, the best known names of which are Hodgkin’s disease, aleucemic leucemia, pseudoleucemia and lymphomatosis. On occasion they are at first localized tumors, being generalized only late in the course; under these circumstances they are usually classed with neoplasms in the form of leucosarcoma and lymphosarcoma. Examples of lymphatic disease answering the above description are limited to two, but even these must be explained in certain particulars. There has already been quoted under leucemia a case of a common Marmoset (_Callithrix jacchus_) which was probably aleucemic leucemia of the myeloid variety; the enlargement of lymphatic nodes was trifling. The case to be cited answers in most respects to the descriptions of systemic lymphomatosis, but there were found two conditions, enteritis and parasitism, which might be responsible for sufficient general toxemia to stimulate lymph nodes and follicles to a state of active growth. Even accepting these two cases as examples of this group, it is very plain that chronic systemic primary lymphatic hyperplasia is an exceedingly rare entity in wild animals. There has been no case resembling Hodgkin’s disease of man.

California Hair Seal (_Zalophus californianus_). Young ♂ four months old. Appeared to be in good health, no loss of flesh or activity.

DIAGNOSIS.—Lymphomatosis. Fatty degeneration of kidneys. Emphysema. Chronic follicular and catarrhal enteritis. Nematodes in intestines.

External appearance good. Both lungs distended and are tense; it seems almost like a spastic dilatation—a simple emphysema—beneath pleural surface are many minute petechiæ. Lung mottled red and gray. This color is present on section. Lobules clearly outlined and separable with fingers. Bronchi and vessels widely open, the latter containing small amount of fluid blood. Lymph nodes—Mediastinal, tracheal and those visible in neck are variously but definitely enlarged, firm, irregular and roughly nodular, both in appearance and to touch. On section they are red and gray, follicular border not preserved and merging with medulla; connective tissue visible; gray juice expressed. Pericardium normal. Epicardium, glistening, transparent and pale. Heart position, size and interior normal. Abdomen contained no adhesions or fluid. Pale brown-red, firm liver with smooth surface and sharp edges; markings not clear; section surface smooth; watery blood expressed from section. Gall-bladder normal, contents limpid, brown. Common bile duct patulous. Somewhat enlarged spleen, soft, yet resilient; capsule smooth; section surface pulp homogeneous brown- purple; follicles gray, slightly enlarged, clear, sharply outlined; trabeculæ faintly visible, more prominent where they are near follicles. Kidney normal in size, shape and location, with smooth, pale brown surface; capsule smooth, strips easily, section surface glistening, consistency soft yet resilient; thickness of cortex slightly wide, of medulla normal; individual lobules clear yet no increase of connective tissue between; pyramids quite pale; top of medulla a little darker; cortices, pale, striæ quite faint and seem irregular; glomeruli not visible. R. Adrenal—In upper pole are two cysts about 1.5 and .8 cm. across; no scar at this point. L. Adrenal— Wide pale purple, regular homogeneous cortex under very dense capsule; medulla reddish brown, homogeneous, quite bloody. In left adrenal is a pale gray, fairly well outlined area between medulla and cortex at upper pole about 3 mm. across.

Stomach.—Contains glass and stones; mucosa, soft, smooth, flat, yellow and pink, translucent rugæ; cardia about normal; pylorus, valve prominent but probably not hypertrophied. Duodenum—Beginning at pylorus and extending through to ileum where follicles commence, intestine contains small amount white, creamy material, serosa negative, mucosa smooth flat, pale pink, translucent. There are small nematodes, probably uncinaria, some of which are attached quite firmly. Here and there throughout the gut are bits of thickened mucosa or submucosa, 2–5 mm. across. Some of these have a tiny opening from which clear fluid can be expressed. Ileum shows smooth flat translucent mucous membrane; empty; individual follicles faint but discernible. Colon reddened mucous membrane, nematodes and little mucus. Pancreas, soft, normal in size and position, color pink gray. The lymphatics of peritoneal cavity are all enlarged; most of retroperitoneal are also. Regional lymph glands are also enlarged. The description given for mediastinal answers here. The glands of mesenteric stalk present chain of sausage-like masses. Glands in mesentery are but slightly affected. Glands within and without peritoneum at kidney are especially enlarged. Large gland behind stomach and pancreas and in front of upper end of spleen is much enlarged, thick and roughly circular; it shows much fibrosis. The regional glands are distinctly enlarged but proportionately not so much as the internal ones. Smear of juice expressed from peritoneal glands shows large and small lymph cells in about proper proportions. There are a few plasma cells. No granular cells.

Smear from bone marrow shows enormous number of premyelocytes and mast cells. Polynuclears in their early stages are not numerous. Small groups of lymphocytes, lightly packed together, noted here and there. Blood smears unsatisfactory.

Microscopical.—Lung shows distended vesicles with considerable congestion of septa and in some places red blood cells in alveoli.

Kidney.—Glomeruli contracted, relatively anemic; capsule negative; epithelium throughout in state of granular degeneration probably fatty; connective tissue not increased.

Intestines.—Show slight hyaline change in muscle fibres and nodular degeneration and disappearance of protoplasm, leaving bare nuclei and outline of the cells; submucosa loose; mucosa shows infiltration of round and plasma cells, diapedesis, degeneration and desquamation of epithelium. Section of ileum shows a hyperplasia of lymph follicles with active centre in which large endothelial cells predominate. Small swellings in submucosa consist of chronic granulation tissue, but there is no foreign body and no evidence of preëxistence of a lymph follicle.

Lymph nodes loosely arranged but in places solidly small lymphoid; chords and sinuses contain chiefly small lymph cells in which are some mast and plasma cells; follicles small and loose, and centres contain chiefly large lymph and plasma cells; connective tissue not increased yet there are some fibroblasts in follicles.

Spleen.—Shows almost entirely hemorrhagic pulp; blood destruction not active; follicles large and made up of about equal mixture of small lymph, plasma and large lymph cells; connective tissue prominent probably because of excess of blood around it.

LOCAL HYPERPLASIAS.

In this group and touching the purely hyperplastic, come the hypertrophies of the lymphadenoid tissue of the nasopharynx; this can be disposed of by stating that no true chronic hypertrophies have been seen. With most cases of gastroenteritis in ungulates, and many in carnivores, there is a swelling and redness of the tonsillar region but an exudative or necrotizing process does not occur.

THYMUS.

The thymus is rarely visible in our specimens but when found has usually been normal. An increase in size and a decrease of consistency of this organ is noted in marasmus (inanition) from failure of care of the young by the parent, but so far as can be determined this has not been adequate to cause tracheal compression. In a few cases of rachitis in the canines, the organ is large and pale along with the rest of the lymphatic system. In one of the tumors of the mediastinum to be discussed, the suspicion arose that the growth originated in the thymus; adenomata and sarcomata have been described in the lower animals.

TUBERCULOSIS.

Tuberculosis of the superficial lymph glands is rare as an independent lesion in the lower animals. Dr. C. Y. White was fortunate in seeing a monkey with a chain of fibrocaseous nodes in the cervical region, upon which before death he offered the suggestion that it was of tuberculous nature. In Primates almost all drainage glands exhibit some miliary or caseous process. One monkey rejected upon the tuberculin test had what was apparently a primary lesion in the glands at the tracheal bifurcation. In the Ungulata, lymphatic tuberculosis assumes two forms, the caseous and the cellular. The former is generally understood while the latter is more uncommon. It is occasionally seen in the “fungous tubercle” of cows, but we have seen it in deer and in another order, Carnivora. In the latter, tuberculosis being uncommon, examples in the lymph nodes were noted but twice, once caseous and once solid; this latter was made up of firm, homogeneous yellow pink masses of glands in the mediastinum, showing under the microscope solidly packed epithelioid and giant cells.

Lymphatic tuberculosis in the birds is rare; only one case is recalled (unfortunately record cannot be found) as small yellow, discrete firm nodules in the mediastinum and neck. The minute picture was of a solid arrangement of large vacuolated mono- and polynucleated cells which were so packed with bacilli that the preparation could not be decolorized.

TUMORS.

The neoplastic enlargements are represented by a lymphosarcoma of the mediastinum in a Dorcas Goat; there were secondary growths in the liver, the kidney and several isolated lymph glands. Secondary growths from original tumors not in the lymphatic system are curiously rare, certainly much less frequent than is found in the human being. In ninety-two tumors which are known to give metastases, only three involved the lymphatic glands and only one of these could be considered as involving nodes not in the ordinary drainage pathway.

THE SPLEEN.

The spleen is an organ whose exact position in the scheme of things remains mystifying through the whole series of animals. Its functions have been arrived at largely by exclusion, somewhat by conjecture and speculation, while the acceptably proven duties are indeed few. Although this is not the place to enter into a discussion of all the points at issue concerning the anatomy and function of the organ, a few facts might be mentioned of comparative and perhaps pathological value. While the spleen has been looked upon always as the origin of blood cells in the embryo, cases in man are on record where no spleen was discovered, a condition suggesting that its absence is not incompatible with life; that such is the case is obvious for experimental or therapeutic removal of the organ is well known.

It was suggested by Virchow that at times the spleen assumes the duty of the bone marrow and the swelling of the viscus in certain anemias seems to support this statement. However, there is no physical relationship between the size of the animal and that of the spleen, nor between the available quantity of bone marrow, the obvious richness of circulating blood and amount of lymphatic tissue. This is well shown in the water mammals which have a great deal of blood in vessels and viscera yet their spleen is relatively smaller than birds of somewhat comparable size (the ostrich, for example). The Carnivora and Rodentia among the mammals, have quite large spleens proportionately, while comparable birds, Accipitres and Striges, have relatively small ones, and an absolutely small amount of marrow.