Part 33

Undulated Grass Parrakeet (_Melopsittacus undulatus_) ♂ . Medullary carcinoma of thyroid. On opening the body a mass 10 × 6 × 4 mm. is found in the upper thoracic region on the right side. A similar mass measuring 5 × 3 × 2 mm. lies in similar position on the left side. They are identified as thyroid glands only from their position and from the numerous large vessels which radiate from them. An especially large vessel leads directly to the heart. Long axes extend anteroposteriorly. The masses are of a firm gelatinous consistency, the color of carpenters glue in lower portions, shading off to a dirty canary yellow above. They have a translucent appearance in lower portions. The surface is fairly smooth, adherent latterly and posteriorly. They are well circumscribed. At one end of the histological section thyroid tissue is easily identified. It varies from normal in that its spaces are often very large, contain villus projections or may be completely filled by large compound granule cells with no colloid. Other acini are atypical and contain typical colloid. Continuous to such thyroid tissue is a very large, rounded tumor. It consists of round cells with round nuclei in which many mitotic figures may be seen. An arrangement into acini cannot be made out nor is colloid material abundant. In one or two places an irregular collection of such material may be seen with peripheral vacuolization but its confines are always indefinite. As far as section goes the mass is well encapsulated but the lymphatics are infiltrated by the tumor cells. The tumor, too, is sharply separated from the relatively normal thyroid. Irregularly scattered through section are remarkable cells with nuclei three or four times the size of other nuclei. They may be hyperchromatic or normally staining. (Figs. 38 and 39.)

The THYMUS BODY is a structure encountered in our specimens with greater regularity than is the case in human autopsy experience. However, no great size of the gland is observed, and there is no record or recollection of anything which could resemble an enlargement suggesting status thymicolymphaticus nor has a tumor with this organ as its origin been observed. In one case only did the thymus present what was believed to be an unusual size. An adult Gray Lagothrix (_Lagothrix lagotricha_) died with an acute intestinal infection. Its thymus was a large, soft, deep pink body lying in the anterior mediastinum, running up to the clavicular joints and down along the sternum. The death had ample explanation without any state of this organ. The thymus body has not been found enlarged in association with thyroid disease.

The SUPRARENAL or ADRENAL BODY is an organ of essentially the same general construction in the two classes here studied except that in birds the cortical portion may be imperfectly developed and in some of the lower groups is decidedly narrow. This outer zone may indeed be entirely missing since tissue comparable to it is distributed elsewhere in the body, notably with ganglia along the vertebral column. The organ is infrequently the seat of alterations, detectable either grossly or microscopically. Congestion and small hemorrhages are rather common in acute infectious disease especially when the respiratory system is involved, but these rarely destroy tissue or materially reduce the chromophilic cells. These circulatory disturbances have, however, been predominatingly among the mammals although birds have suffered with infections to a high percentage. The medulla is much more often the seat of congestion while, when hemorrhage has occurred, the cortex is apparently always involved. Lipoidal reduction has been seen in a few mammals, Primates and Carnivora, once to a state of complete exhaustion. More serious lesions have occurred eleven times, and since the cause and meaning of disease in this body are so vague it seems well to recite briefly each one.

A Weeper Cebus (_Cebus capucinus_) suffered for several months with constantly but slowly increasing skeletal deformity of the osteomalacic variety. He died after moving him to a new cage, his end being hurried by a scalp wound. At autopsy the skeletal condition was determined to be of the above named kind. The organs were in good condition. The adrenals were decidedly enlarged for a monkey of this size, measuring 1.8 cm. in length. The medulla was a solid, brownish, homogeneous portion covered with a very narrow, barely discernible cortical zone. This was apparently due to a uniform hypertrophy of the cells of the medulla. The testes were slightly atrophied and fibrotic. A Black Spider Monkey (_Ateles ater_) had a history of stiffness of legs for six months. This was probably a sign of osteomalacia since at autopsy this condition was found together with a secondary anemia, chronic gastritis, acute enteritis and brown atrophy of heart. The adrenal was knob-shaped, the cortex was wide, brown, regular, the medulla small gray-purple. “Histologically the capsule of the adrenal is thicker than is commonly seen in Primates and connective tissue bands between the units of the zona glomerulosa are somewhat stouter than common. The cells of this layer take the stain a little more deeply than usual, but are otherwise negative. The layer separating cortex and medulla is occupied by a band of well formed connective tissue which is not proceeding inward but outward and so encroaching upon the zona reticularis as to remove it completely in places, in others to make isolated islands of its cell groups. Fine lines of connective tissue are penetrating from this into the middle layer but not disturbing it as yet. The connective tissue septa penetrating the medulla are somewhat wider than one would expect but show no activity in their growth. The medulla is somewhat broken up, vacuolated and the chromophilic cells are not especially prominent, indeed some of them seeming to have undergone necrosis.” A puma (_Felis concolor_) died after a sickness of two weeks from acute gastroenteritis with its usual visceral associations, including acute nephritis, and with calcifications in the adrenals. These structures were quite firm and nodular, on section tough and resilient. “The cortex is irregular, brown, with paler brown medulla. Areas of calcifications appear as small dots, as linear formations and in some places seemingly around blood vessels. Histological section shows marked vacuolization of cells, particularly of cortex. There is a diffuse overgrowth of connective tissue which has become hyaline. Here and there small calcareous deposits may be seen but no massive areas as mentioned above.”

A Himalayan Thar (_Hemitragus jemlaicus_) came to his end, after a history of convulsions, from nephritis, which had resulted in general edema including the serous sacs, and an associated cardiac dilatation. His adrenal was egg-shape, of normal size, with a wide, irregular dull brown cortex and a homogeneous opaque, darker brown medulla. “Histologically the cellular structure of the cortex is partly destroyed, partly dropped out and partly disturbed by overgrowth of connective tissue. This connective tissue is quite prominent in the medulla where it is surely increased although it is made more prominent by absence of cells, some of which have been degenerated and some dislodged.” A Japanese Macaque (_Macacus fuscatus_) after drooping three weeks presented at autopsy the following numerous lesions: anemia, chronic atrophic gastritis, atrophy of heart muscle with regeneration, hemosiderin pigmentation of liver, perilobular fibrosis of liver, chronic diffuse nephritis (subcapsular type), congestion of spleen, fibrillar fibrosis of spleen, hemosiderin pigmentation of spleen, local amyloid infiltration of spleen, calcareous infiltration in medulla of adrenal. Grossly the adrenal showed a thick, orange yellow cortex and small solid, brown medulla. “Histologically the organ appears normal in all respects save for the presence of a few small irregular areas of calcification in the medulla. These occur apart from any recognizable necrotic or fibrous areas. In one place one appears to lie within the lumen of a blood vessel. No fibroses or special congestions found anywhere in the organ and cells show normal details and normal numbers of vacuoles.”

A California hair seal (_Zalophus californianus_) which had been refusing food and having loose stools for about ten days presented after death the following diagnosis: Hypernephroma of adrenal, chronic hypertrophic enteritis with acute exacerbation, hemorrhagic splenitis, passive congestion of liver, congestion and edema of lungs with catarrhal pneumonia, acute fibrinous pericarditis, chronic lymphadenitis, chronic interstitial nephritis. His right adrenal seemed about normal, being 5 × 2 × 1 cm. with a narrow, dull yellow cortex and a large mottled gray-brown medulla. The left one was 5 × 3 × 1 cm. The upper pole is swollen and contains in its centre a spherical tumefaction which is red, mottled, sharply outlined, with a suggestion of a capsule and slightly firmer than surrounding organ. “Histological section shows a capsule of very noticeable thickness but possibly not much in excess of normal. The cortex particularly in its deeper layers is much injected and in some places there has been hemorrhagic diffusion. In many places in the zona fasciculata, more especially near the periphery, there is breaking up of the cell tubes with an infiltration of large round cells and some chromatophilic cells. In other places this seems to have gone on to fibrous tissue increase and necrosis of the cortical fibrous cell types. The connective tissue layer below the cortex is wide and the spaces filled with blood. This connective tissue also surrounds islets of medullary cells which are not specially chromatophilic. The mass in the medulla is made up of varying sized alveoli surrounded by rather rare, highly vascularized connective tissue and enclosing islets of medullary cells. These alveoli may be subdivided by septa. Hemorrhage has occurred into many of them. The individual cell masses are made up of groups of rather large cells with illy defined margin, a granular, opaque but not vacuolated protoplasm. They have a bladder-like nucleus in which the centrosome is large and prominent. Definite mitotic figures could not be found, but mitosis is probably present. A few cells with double nuclei were seen and one with four. In many of these large islands the centre has gone to pieces from hemorrhage or necrosis. Some of the vessels are thrombotic and one shows a very pronounced periarteritis.” A brown cebus (_Cebus fatuellus_) was killed because of a poor tuberculin test chart. His organs were negative except the right adrenal body which was 3 × 1.5 cm., or four times the size of its fellow. It was a tense body with a smooth, mottled, deep yellow surface. On section there were deep yellow islands separated by pale brownish septa; the structure did not resemble adrenal. Histological section showed a hypernephroma of vacuolated cell type, roughly alveolar. Two other cases, which because of their microanatomy are to be called hypernephroma can be added to those just cited. One occurred in an undulated grass parrakeet (_Melopsittacus undulatus_), the other in a black duck (_Anas obscura_). As illustrative of this tumor the former will be cited in brief. “Hypernephroma of adrenal with hemorrhage into body cavity. A tumor approximating in size the head of the host extends from the region of the internal genitalia and adrenals lying more on the right than on the left side extending fully to cloaca and shoving all abdominal viscera forward. It has a pedicle springing from between the two upper lobes of the kidney where adrenals and internal genitalia are not distinguishable. Tumor is coarsely lobulated, well encapsulated, nowhere adherent. It has a pale, dirty yellow color, richly marked by red lines of congested vessels. It is fairly soft, _i.e._, about consistency of normal liver. Upon incising, the cut surface bulges markedly, is a dirty gray-yellow, blotched with darker gray areas, shows no internal hemorrhages or markings of special import. No metastases noted to any other organ. Microscopic section shows a light capsule surrounding the tissue of the tumor. The latter has a very scanty fibrous reticular framework showing no orderly or purposeful arrangement. Upon and between the reticulum, irregular and for the most part elongated collections of cells are placed. At times these present an elongated fascicular form, but this is not by any means a prominent feature. The cells themselves are large, rounded or polygonal, have coarsely granular cytoplasm which only in rare cases contains vacuoles. Nuclei of these cells stain very poorly, but it can be made out that they are of large epithelial type and of vacuolar appearance.”

A somewhat unusual tumor was encountered in a Polar bear (_Ursus maritimus_), an adenocarcinoma of the adrenal, when judged purely by its histology but a secondary tumor in the lung displayed the more familiar picture of large vacuolated cells as seen in hypernephroma. The diagnosis follows: “Scirrhous adenocarcinoma of adrenals, secondary carcinoma of lymph glands, secondary hypernephroma of lung, secondary carcinoma of diaphragm, acute mucopurulent bronchitis, acute catarrhal enteritis, chronic diffuse fibrous cholecystitis, cholelithiasis, slight acute interstitial pancreatitis, follicular hyperplasia of spleen with fibrosis, hydrothorax, hydropericardium, chronic hypertrophic osteoperiostitis, encysted trichina in diaphragm, fatty infiltration of diaphragm, chronic diffuse nephritis, chronic productive lymphadenitis, pigmentation of lymph gland. Both adrenals are smaller than normal, of woodeny consistency, the pale cortex and medulla are poorly separated from each other. The cut surface shows gray white and tawny mottling and occasional calcareous points. Histological section shows an extra capsule of fibrous tissue containing highly distended veins; the lining contains masses of tumor cells, many of which are necrotic. It is distinctly denser in type than normal and more abundant in places showing a proceeding fibrosis. Parenchyma shows but few irregular islands containing non-neoplastic cells, some of which are highly vacuolated, others are not. Interstitial tissues in peripheral parts are often grown together with the deeper portion where are intermixed tumor areas. The latter consist of small round acini of variable size lined by cells of active type. Nuclei are large and hyperchromatic, cytoplasm broad and disintegrating. Parts show necrosis and hemorrhage. Upon search transitionals from non-neoplastic to neoplastic cells can be discovered in same fasciculus.”

SECTION XII THE SKELETON AND ITS JOINTS

The bones with their articulations have been the subject of extensive study and research by zoologists in the direction of classification and evolution. Adaptation of the osseous construction to the needs of the animal is well appreciated biological knowledge. For example, the keel of the sternum in birds affords broad origins for the flying muscles, the pectorals, which also insert on the alæ of this bone and on the clavicle, and in addition use these latter formations as fulcra. So too the extremities of quadrupeds are angular in their upper two segments for the purpose of supplying a direct action of the flexors employed in running and leaping. The thick masseter muscle of carnivores is accommodated in the deep zygomatic fossa. Many other examples might be cited, but these serve to direct attention to the adaptation of function and construction. Pathological changes in our materials are however too few to permit conclusions as to possible relation of zoological position and development except such as may refer to deformity incident to the degenerative processes—rickets, osteomalacia and osteogenesis imperfecta, and in these conditions the alterations are merely passive accommodations to weakened support in order to obtain comfort. To put the matter in other words, it would seem that, aside from the diseases just named, there is no outstanding change in the skeletal tissues peculiar to zoological orders that might indicate vulnerability of the system or the methods of response to injury or disease.

EFFECTS OF TRAUMA.

There must be considerable reserve or reconstructive power in the bones of animals since it is a common thing at autopsy to see unmistakable evidences of repair of fractures, dislocations and inflammations. Some illustrations are introduced to exemplify this healing ability, one of which was found in an animal shot by a hunter, the other an incidental autopsy discovery. Even though there be no definite relationship between the zoological order and osseous disease, it is interesting to record a very simple observation. Animals with long extremities, especially when the bones are quite near the skin, have a rather high incidence of fractures and inflammations. Thus the ungulates have of all orders the highest percentage of these traumatic and infective lesions; herons and gallinaceous birds follow the ungulates. Marsupials, primates and carnivores, in this order, are susceptible to inflammations but not to fractures. Bones are often broken, among the Cervidæ, Bovidæ and Camelidæ, when as they are chased by mates, they fall upon the slippery floor of the cages; or again the mounting of a small animal by a large buck may crush the former to the earth. Two cases of fractured pelvis have been seen in antelopes from a fall with extended hind legs.

It would seem that repair is usually satisfactory if the animal has a quiet retreat where callus may form and union occur. A heron is known to have broken both bones of the leg; at autopsy a very insignificant circumferential callus remained, the member being as straight and strong as normal. Figure 40 shows the femur of a deer shot by a hunter; the shortening was considerable, but function was doubtless good because the hunter could perceive no limping as the animal ran. The most interesting fracture among our records was an intracapsular fracture of the hip in a Huanaco (_Lama huanacos_) shown in Figure 41. This animal slipped on the ice in December and was thought to have broken something near the hip, but it limped around without any great show of pain until the following May, when it died of meningitis secondary to an _otitis media et interna_. At autopsy an unhealed, complete fracture of the neck of the right femur was found, apparently separating the head from the neck, the former being dislocated to the upper angle of the obturator foramen. Everywhere about the joint callus had been thrown out, but not in a manner to effect a junction of the broken ends nor to seal the edge of the acetabulum to the femoral neck. This was probably due in part to the irregularity of the line of fracture and to the interposition of the upper part of the dislocated head between the lower rim of the acetabulum and the surgical neck of the bone. When the specimen was fresh traces of capsule were found over the upper half of the acetabulum. While it is usually difficult to decide the manner in which these injuries effect their damage and deformity, it might be ventured to explain this case as due to extreme posterolateral extension of the leg driving the head of the femur downward and inward, rupturing the capsule and the ligament bridging the acetabular notch, to rest on the pubis at the upper edge of the obturator foramen where it could find a sort of joint cavity made by the pubic and ischial segments of the old acetabulum, but about an inch and a half below its normal location.

Another injury to the hip joint was noted in a Livingstone’s eland (_Taurotragus oryx livingstonii_). This beast was not positively known to have fallen, although it was suspected that such an accident had occurred by reason of sudden inability to rise. At autopsy, death having succeeded on signs of shock, a complete upward and backward dislocation of the right femoral head was found; there was also an intracapsular rupture of the left round ligament, but on this side the femoral head had not left the acetabular cavity.

Many other fractures have been observed but generally without interesting features. The conclusions which may be drawn from our experience are that animals with long bones, and liable to chase have the greatest liability to fractures, and that the healthy beast, given seclusion and quietude, possesses great ability to heal its broken bones. Pathological fractures are occasionally seen. (Consult notes on cretin wolves.)

Before entering upon a discussion of the most important of osseous lesions, rickets and osteomalacia, certain inflammatory states may be appropriately described.

INFLAMMATIONS.

Hypertrophic osteoperiosteitis: A male lion (_Felis leo_) at the Garden three years died, after being out of condition for a long time, from chronic ulcerative pulmonary tuberculosis with terminal pneumonia, nephritis and enteritis. Both hind feet had been observed as enlarged and apparently painful for some weeks before death. Upon dissection the bones of both hind feet are the seat of extensive hypertrophy, and the periosseous fibrous tissues are thickened. A large mass about the size of a small orange lies attached to the outer side of each ankle. The hypertrophic periosteitis extends up the tibia a distance of about three inches and the fibula for about the same distance. These two bones are adherent to each other for about 1½ inches. The joint between them and the tarsal bones is apparently perfectly free. The calcaneum is the bone most severely involved; on this is a large rounded mass which extends on the bone for a distance of about 2½ inches. The small bones of the foot are more or less severely involved but are not bound together, the joints being practically free. The terminal and next phalanges are entirely free from disease while the metatarsals are severely involved and grown together into one large mass. On section this appears as a mass of spongy bone lying on top of the cortex. In the dried specimen this looks very like old pumice stone. Histological section shows the periosteum raised from the bone by mononuclear infiltration. The bone marrow spaces are filled by a very delicate gelatinous material. The lamellæ are thickened. A photograph of the foot with a normal example is given. (Fig. 42.) (See also Tuberculosis section—Carnivora.)

A cockatoo died from acute miliary tuberculosis; the upper thoracic and lower cervical vertebræ are involved in an S-shaped scoliosis which reduces the height of the thorax by perhaps a centimetre. Thorough dissection was not made, the trunk being kept as a museum specimen and for study in event another avian scoliosis occurred; but from palpation, separation of the muscles and stretching of the spinal column it does not appear that a tuberculous osteitis of the vertebra existed. It seems that this may be due to congenital deformity or old injury.

A white-nosed coati (_Nasua narica_) suffered with generalized tuberculosis which also affected the wrist joint with a caseous and ulcerative arthritis.