that observed in human tuberculosis more than in cattle tuberculosis. In fact, the disease bears many points of similarity to infantile tuberculosis in the human. There may be tuberculosis pneumonia involving large areas of the lungs, causing collapse of the marginal portion. There may be irregular-sized grayish or yellowish areas of caseation, as is so often seen in cattle; but not infrequently there are observed large numbers of miliary gray or translucent foci, showing evidence of generalization as a result of the bacilli being disseminated by the blood stream. (See Pl. II.)

The picture presented by tuberculosis of the spleen, which showed lesions in 3.8 per cent of the above carcasses, is very peculiar to one who is familiar only with cattle tuberculosis. The spleen is usually darker in color and the surface is quite rough and nodular, depending upon the number and size of the tubercles. Unlike the spleen of a tuberculous cow, these nodules occur not often on the serous membrane, but in the parenchyma. They vary from the size of a half pea to as large as a shellbark. The external pale or light-red nodules are raised above the surface of the organ and frequently show fibrous tissue bands radiating from the centrally necrotic area. (See Pl. III.)

The lesions observed in the mediastinal glands are similar to those in other glands and were noted in 1.8 per cent of the cases, while the sublumbar glands were found affected in 0.9 per cent of the carcasses. The serous membranes may show an eruption of tuberculous granulations, and these have been noted on the pleura in 0.1 per cent and on the peritoneum in 0.006 per cent of the cases. The generative organs are rarely affected. The bones, however, are more frequently attacked, those of the vertebral column, pelvis, and of the articulated extremities showing tubercular affection in 0.007 per cent of the carcasses. Tuberculosis of the muscles has been noted, but not so frequently as of the bones and joints. The lesions are usually rather limited to one region. Their aspect varies. They may be rounded, isolated nodes of the diameter of a pea or bean, composed of a fibrous capsule, with caseous contents. In other cases the muscles are sown with whitish-gray confluent tubercles, with centers that are usually calcified early in the development of the disease. The extreme rarity of lesions in the kidney is shown by the finding of but 3 cases in the 120,000 tuberculous carcasses. As examinations of the prepectoral, prescapular, and inguinal glands were not made in all instances, no percentages are given for them.

Occasionally also ulcers and tuberculous nodules are noticed on the mucosa or submucosa of the small intestines, especially of young pigs, but these likewise are rare, and when found usually accompany generalized lesions elsewhere in the body.

COMPARISON OF THE TUBFRCULOUS LESIONS OF HOGS AND CATTLE.

While the lesions in hogs may be considered in their principal features like those in cattle, there are some points of difference which may be readily noted. As the disease in the former animals is essentially a food tuberculosis, the primary seat of infection is almost universally along the alimentary canal. The submaxillary glands are more frequently affected than any other tissue in hogs, while in cattle these are quite infrequently diseased. In fact, the submaxillary glands of hogs bear a somewhat similar position to the retropharyngeal glands of cattle, although the former are more frequently affected in hogs than the latter are in bovines. The lungs are less frequently diseased and generally secondarily involved, not primarily as in cattle. Furthermore, the pleura and the peritoneum are even less commonly affected than the lungs. The liver and the spleen, especially the latter, are more often diseased in hogs. The mammary glands of hogs are less frequently affected than in cattle, while the bones, joints, and muscles are more liable to disease in hogs. The lymph glands, even those remotely situated, are more frequently affected than in cattle (with the exception of the mediastinal gland, which is only occasionally diseased in hogs), and there is a very large percentage of this disease in hogs which only shows involvement of one, two, three, or even more groups of lymph glands without regular secondary infection.

Ulcers in the intestines, while infrequent in both species, are probably more commonly observed among swine. The formation of grapelike clusters on the parietal serous membranes is quite infrequent, and when it is seen it usually results from contact with an adjacent tuberculous organ. The lesions undergo calcification much earlier in hogs, and this form of degeneration occurs as often as, if not oftener than, in cattle, and frequently takes place when the lesions are quite small. The tubercle bacilli are quite elusive on microscopic examination, but are more readily seen in our experience with hog lesions than with bovine. Finally, unlike the disease in cattle, tuberculosis of hogs is most frequently seen at the abattoirs in animals under 1 year of age, due, of course, to the fact that the majority of hogs are marketed at this age.

RELATION OF HOG TUBERCULOSIS TO MEAT INSPECTION.

The post-mortem inspection of hogs by the Bureau officials is very thorough, and is so arranged that tuberculous carcasses are quickly separated from those that are healthy. The various phases through which the hog passes after his arrival at the stock yards, where he is yarded, sold, weighed, driven to the packing house, killed, scalded, and run through the scraper, do not particularly concern us until we

meet him at the point where, lying on the traveling table, his head is almost severed from the body. Here he is examined by a veterinary inspector of the Bureau, who palpates and, if necessary, incises the submaxillary glands which have been exposed by the cut just made by the butcher for removing the head. Should these glands prove to be healthy, the hog is allowed to pass down to the rail unmolested; if on the other hand these glands are seen to be tuberculous the animal is marked and is then run into a separate compartment called the retaining room, without being eviscerated. Most of the tuberculous animals are detected here at the header's bench, our records, as previously mentioned, showing that 93.3 per cent of the tuberculous hogs support lesions in the glands in the region of the throat.

From the header's bench the hogs which have not been tagged are sent along the rail to the gutter's bench, where another veterinary inspector is stationed, whose duties consist in examining each hog, giving special attention to the viscera. His search is not limited to the detection of tuberculosis, but he must watch for any of the diseases proscribed by the regulations of the Bureau. As there is a certain percentage of hogs that show tuberculosis in the visceral organs without giving any evidence of the same in the cervical glands, the inspector at the gutter's bench is able to detect a number of tuberculous subjects in addition to those already tagged by the veterinarian at the header's table. In this case the inspector is guided by the appearance of the lesions in the liver, spleen, lungs, or visceral glands.

Another inspector has recently been installed at the point on the line where the carcasses are split, it having been found that occasionally vertebral lesions and lesions of the serous membranes will exist, even when the visceral organs are apparently normal.

Returning to the hogs which were tagged by the inspector on the heading bench, these are passed along to the retaining room, where they are eviscerated by a separate lot of butchers, using separate tools, under the supervision of a fourth veterinary inspector. By this method the affected parts or tissues are prevented from coming in contact with the healthy meats and are passed directly from the retaining room to either the " condemned" room or to the offal tanks. In the retaining room by this time there will be many hogs on the rail that are only slightly affected with tuberculosis, and these are now beheaded, split, trimmed, and passed on to the cooling rooms.

It is not a very difficult problem to pass judgment on the carcass of a hog affected with tuberculosis when the lesions are slight on the one hand, or when they are widespread on the other. Most sanitarians are agreed to pass the former class for food, after removing the diseased parts, and to condemn the latter class. In the great majority of hogs retained by our inspectors the lesions are local, even