Third-That while unsanitary conditions, as crowding, impure air, improper food, high subsoil water, trades involving irritation of the air passages, riotous living, and the presence of wasting diseases, may greatly facilitate the invasion of the bacillus into the system, yet in themselves cannot possibly produce this distinct disease.

MORBID ANATOMY OF TUBERCULOSIS.

DR. F. B. WYNn, of Indiana State Board of HEALTH.

Bacteriology has opened the eyes of sanitary science to a new world for conquest. Whereas we were blind, now we see. The invisible enemies of mankind are found to be more numerous and more terrible than those seen. But of the many tribes of unseen foes, none is so numerous and enduring, none so widespread, powerful and hostile to man and beast as those which rally under the standard of tuberculosis. This greatest sanitary body of the Western Hemisphere has wisely and opportunely chosen as chief topic for consideration its greatest enemy. To the writer has been assigned the duty of reading the scripture as laid down in the book of science-the mere narration of facts. To others falls the preaching of the sanitary gospel-the plan of campaign against the foe. The character and allies of our adversary have been already graphically set forth. It remains for us to describe the wounds and devastations produced. So accustomed are we to them that we are not terrified as by an onslaught from cholera, which attacks a city to-day and to-morrow leaves it depopulated. Yet the tubercle bacillus has slain its thousands where the cholera germ has slain a single victim. It is only as we study the nature, frequency and extent of these ravages that we are brought to a full realization of the terrible enemy with which we have to cope.

It is but a few years since the lungs were supposed to be the exclusive seat of tuberculosis. Microscopical, culture and inoculation studies have since shown that scarcely an organ or tissue is exempt from attack.

GROSS FEATURES OF TUBERCLE.

The sine que non of tuberculosis is the tubercle germ. It is the bacteriological unit as the tubercle is the anatomical unit of the disease. The former constitutes the exciting cause; the latter represents the resulting sequence of changes, constructive and destructive in character, provoked primarily by the tubercle bacillus, secondarily by other microorganisms. The tubercle is nearly always present, but does not invaribly characterize tuberculous changes. The etymological significance of the term tuberculosis is fullness of tubercles, or nodules.

In its gross features tubercle varies according to its age and tissue environment. Young tubercles are gray, old ones white or of a yellowish cast. They range in size from a pin point to a pea, the average being that of a millet seed. In bovine tuberculosis the nodules are much larger, often attaining the dimensions of a walnut or an orange.

HISTOLOGY OF TUBERCLE.

The evolution of a tubercle begins with the invasion of a tubercle bacillus. The rapidity of growth will depend on the number of germs, the kind of tissue invaded, its tone and individual vulnerability. There occurs first a rapid multiplication of the fixed cells, which are large and from their epithelial-like appearance spoken of as epithelioid cells. Generally they contain one or two nuclei; occasionally many nuclei, constituting giant cells. Notwithstanding the exuberance of cell proliferation, new capillary formation does not take place within the nodule. It remains a non-vascular growth.

Alteration in the vessels around the tubercle occurs sooner or later. leading to extensive emigration of the white blood corpuscles. They collect in great numbers at the periphery of the nodule, and many infiltrate more or less throughout its entire extent. The changes thus far are progressive. The tubercle has reached its full development, and further changes are likely to be retrograde. The cells at the center gradually die out-first the small, later the large ones. The nuclei shrivel and disintegrate. Ultimately the cellular substance may be transformed into a hyaline or granular mass, abundant in fat granules, cheeselike in appearance. Change in color likewise takes place from gray to white or yellow. This is known as caseation.

In the meantime nature has busied herself in trying to eradicate the diseased area. The rim of small round cells around the tubercle is gradually transformed into fibrous connective tissue. Nature thus attempts to isolate the focus of infection by throwing about it a sanitary wall. That it often proves effective no pathologist of wide observation will demy.

Not infrequently tubercle is invaded also by pus germs. Suppurative softening results, known as "mixed infection."

With these general considerations of the morbid anatomy and histology of tubercle we may now take up some of the multifarious organic and tissue changes which result from tuberculosis.

RESPIRATORY SYSTEM.

The common impression among the laity that tuberculosis is exclusively a lung disease arises partly from its gravity when present in these vital organs, and partly from the fact that in other organs and tissues the disease often takes a different name.

Chronic phthisis is by far the most common type of pulmonary tuberculosis. Beginning at one or both apices, it travels downwards, infecting radially, contiguous tissue by the lymph channels, more remote parts through the blood current, or by aspiration of the tuberculous matter through the bronchial tubes into different portions of the lung.

Small areas of pneumonic inflammation always attend chronic phthisis. These occur in connection with the bronchioles and around the tubercles. If the tubercles are very numerous, this inflammatory infiltration may become so extensive as to solidify the entire lung tissue, just as in acute pneumonia. The air-spaces fill with blood corpuscles, epithelial cells and fibrin, which, together with the tubercle, undergoes caseation and softening, with the production of cavities. The destructive process arises in most cases from the invasion of pus germs, although to a certain extent ulcerative changes may be brought about by the tubercle bacillus.

The cavities may be no larger than a hazelnut, or occupy an entire lobe. When freshly formed they have ragged walls, covered by caseous, necrotic and purulent debris. Chronic cavities have well-defined fibrous walls, with occasional bends passing from side to side and supporting partly destroyed blood vessels. From ulcerations of these vessels they often dilate at points and burst, with resulting hemorrhage. In nearly all cases of pulmonary tuberculosis the pleura, bronchi and bronchial glands show tubercular involvement, as well as inflammatory effects provoked by pus micro-organisms. In every case of phthisis there are tubercular masses or cavities which have been more or less completely isolated by fibrous tissue encapsulation. Cure may be effected in this

way.

With some individuals this conservative effort is manifested wherever tubercular infection appears. Sanitary barriers are thus thrown up which inhibit the advancement of the disease. This form is known as fibroid phthisis, and such persons often live years. The lung may become shrunken and puckered till its respiratory capacity is practically nil, while the opposite lung is voluminous in proportions.

Acute phthisis, or galloping consumption, is secondary to a tuberculosis focus, which may be a cavity in the apex or a softened gland. By aspiration during respiratory or coughing efforts, softened tubercular matter is drawn into greater or less areas of the lung substance. So, from numerous new foci and the attendant round-celled infiltration and exudation, the lung may become solidified, as in acute pneumonia. The resemblance on section may be striking, and the closest search necessary to discover the miliary tubercles. More characteristic are the latter stages of the disease, when caseation and softening give a yellowish background, with the coarse pigmented network of connective tissue.

Secondary tubercular ulcers of the larynx and epiglottis are frequently seen by the throat specialist, and familiar to us all in the rasping, whispering voice so often noted in the last stages of phthisis.

LYMPHATIC SYSTEM.

In tubercular disease of the lymphatic glands, one of three sets is usually infected the cervical, bronchial, or mesenteric. These are the gateways to the lymphatic system. Catarrh or abrasion of the mucous membrane is favorable to the entrance of germs. Hence whooping cough, measles and chronic intestinal disorders in children open the gates, as it were, for the entrance of the bacilli to the gland. The glands of the neck are most frequently involved. Fortunately, the disease is generally local, and tends to spontaneous cure. From septic infection the cheesy masses frequently break down, discharge, and healing takes place slowly, with the production of puckeirng scars, so often observed on the neck. The bronchial glands are frequently involved. Northrup found them infected in all of one hundred and twenty-five tubercular children examined post-mortem. The danger of tubercular adenitis in this region is of perforation into one of the great vessels at the base of the heart leading to general tuberculosis, or of penetrating the œsophagus, bronchial tubes, pleura, or pericardial cavities, and so cause disastrous extension of the disease.

Tubercular disease of the mesenteric and omental glands is common. Out of one hundred and twenty-seven fatal cases of tuberculosis, one hundred showed involvement of these glands. In another group of one hundred and forty-four children dying of mesenteric tuberculosis, fortyfour had no ulceration of the intestines. The inference of practical value Ito us as sanitarians is that infection took place in these cases through the absorption of infected food-probably milk.

It would seem that the lymphatic glands are more frequently the seat of tuberculous disease than any other organ in the body. In scarcely a case of pulmonary phthisis do they escape secondary involvement, and it has just been shown that they are often primarily affected.

SEROUS MEMBRANES.

The modern trend of opinion is that most cases of pleurisy are tubercular. Fiedler aspirated one hundred and twelve cases of pleurisy with effusion, of which sixty-six were found to be tuberculous. Of four hundred and fifty-one cases of pleurisy collected by Sears, 39 per cent. manifested tubercular disease. Osler found 32 per cent. clearly tubercular in character out of one hundred and one consecutive cases. Unquestionably, inoculation tests with the effusion would have shown a much larger proportion. Although gross appearances and microscopic examination may oftentimes fail to reveal a tubercular basis, all careful observers are impressed by the frequency with which pleuritic cases with effusion afterwards manifest outspoken tuberculosis.

The exudate in these cases is usually sterile; opalescent or greenish in tint, again hemorrhagic or sero-purulent. The microscope shows few leucocytes, and the bacilli are difficult to detect. Inoculation experi

ments upon animals are important for diagnostic purposes. Tuberculous pleurisy arises by direct extension from the lungs or bronchial glands, rarely from neighboring tuberculous bone.

Tuberculous peritonitis is a primary disease in a small proportion of cases. The Fallopian tubes and intestines are common sources of infection: rarely it arises from the same condition in the prostate and seminal vesicles. The acute form is marked by a sero-fibrinous or sanguineous exudate, and the entire membrane is found studded with miliary granulations. The chronic type is more frequent. Large caseous nodules develop, which may sometimes be felt through the abdominal wall. The exudate is usually purulent, and may become sacculated, ulcerate and discharge into the bowel, abdomen, or through the abdominal wall. In the sclerotic type the omentum oftentimes becomes drawn into a dense puckered mass, and occlusion of the bowel results from adhesive bands.

DIGESTIVE SYSTEM.

Through abrasions of the tongue, and bathing the organ in matter expectorated from the tuberculous lungs, small tubercular areas form. These coalesce and break down, leaving a grayish, punched-out ulcer.

The tonsils are frequently the seat of tuberculosis-primarily infected through food, secondarily by sputum contaminated from other lesions. Strassmann found the tonsils invaded in thirteen out of twenty-one autopsies on tuberculous subjects; another authority in all of fifteen cases. Schlenker believes the majority of the cases of tuberculosis of the cervical gland arise through infection of the tonsils. The exposed position of the latter, and the frequency with which they are abraded and diseased. would support this view.

By direct extension from the larynx, a painful ulcerative pharyngitis often arises. Adenoids of the naso-pharynx may occasionally be tubercular. Consumptives unavoidably swallow more or less infected sputum with their food. Infective material may thus be transplanted from the lungs to any portion of the gastro-intestinal tract. Esophageal tuberculosis is rare. The most frequent source of infection is the bronchial glands. The writer recently made an autopsy in which enlarged tuberculous glands had by pressure caused esophageal obstruction and death by starvation.

Miliary tubercles of the gastric walls occur, secondary to intestinal disease, but ulceration is rare.

In a majority of cases intestinal ulceration is of a tuberculous nature. Primary tuberculosis of the intestine is limited almost exclusively to infancy-infection taking place through milk from a tuberculous animal. Secondary bowel tuberculosis is exceedingly frequent in adults. Frerichs found intestinal ulceration in 83 per cent. of two hundred and fifty cases of chronic phthisis. In another series of one thousand cases, the bowels were affected in five hundred and sixty-six.

The regions chiefly attacked are the lower portions of the ileum, the cæcum and colon. The disease begins in the lymph nodes of the intestinal wall. Individual nodes of Peyer's glands are destroyed by tubercular ulceration, while others remain intact, giving to the patch an irregular, worm-eaten appearance. This is in marked contrast to typhoid fever, in which there is uniform ulceration over the entire area of the plaque. Ulceration extends along the course of the vessels, transversely around the bowel. Hence they are sometimes spoken of as "girdle ulcers." By coalescence of ulcers, extensive areas of the mucosa become destroyed. The tuberculous process extends to the muscular layer, and frequently tubercles may be seen just beneath the peritoneal covering of the intestine. Perforation of the bowel, peritonitis and cicatricial stenosis, with symptoms of obstruction, are not infrequent complica

Fistula in ano often develops in tuberculous patients. Out of six hundred and twenty-six patients suffering from pulmonary tuberculosis, thirty-three, or 5 per cent. had fistula.

NERVOUS SYSTEM.

Acute tuberculosis of the brain membranes is the most frequent and important of all meningeal affections. The disease is largely confined to childhood, between the ages of one and five, although adults may be attacked. In a few cases the affection seems primary, but almost invariably it arises from some pre-existing tuberculous lesion, as of the lungs, lymphatic glands, bones or joints. The tubercular poison gains entrance to the blood and is carried to the vessels about the base of the brain; hence the disease is often spoken of as basilar meningitis. The walls of the vessels, especially about the Sylvian fissure and optic chiasm, become infiltrated with minute, miliary tubercles, which produce more or less occlusion and inflammation. There may be only a turbid serous exudate, or again it is fibrino-purulent in character. The lateral ventricles are distended with fluid, constituting acute hydrocephalus.

Tuberculous brain tumor generally develops in youth. The growth is very slow and associated with tuberculosis of other organs. They vary in size from a pea to a lemon, and are nearly always attached to the membranes. They are grayish or yellowish cheesy masses.

The insanity of phthisis is a clinical condition, familiar to every medical officer connected with the care of the insane. Every hospital for insane contains many patients suffering from pulmonary phthisis. In many of these the insanity is directly traceable to tuberculosis. Of one hundred and six insane patients suffering from tuberculosis, Mickel found thirty-six whose insanity was clearly due to this cause.

GENITO-URINARY SYSTEM.

The genito-urinary organs may be invaded by tuberculosis singly, successively or simultaneously. So far as our knowledge goes the disease seems frequently primary in these organs.

The brilliant surgical attainments of modern gynecology have added much to our knowledge of tuberculosis of the female gentalia. Winckel states that 1 per cent. of tuberculous cases is of these parts. Kelley found a tubercular condition in about 8 per cent. of all tubes and ovaries removed. From microscopical examination it was demonstrated that many of the cases of supposedly simple salpingitis were in fact tubercular. The Fallopian tubes are not infrequently affected primarily.

The disease begins at the peritoneal extremity as a catarrh in which the gray nodules soon appear, undergoing successively caseation and ulceration. From here the diseased process may extend to the cavity of the uterus and vaginal walls. The ovaries are less frequently attacked.

Tuberculosis of the testes is a common affection both as a primary and secondary disease. It begins as a dense nodule at the back of the organ, in the epididymis or testicle proper. The nodules increase in size and number and may lead to the utter destruction of the organ. The disease may ascend along the vasdeferens, involving successively the seminal vesicles, prostate and bladder. The prostate gland rarely escapes in uro-genital tuberculosis. Through invasion of pus germs from the urethra it becomes the seat of mixed infection. An abscess forms which burrows extensively and opens into the urethra or rectum.

The kidney is not infrequently involved in generalized tuberculosis, the whole renal substance being infiltrated by miliary nodules. In primary disease of the organ the tubercles are generally found just beneath the mucous membrane covering the pyramids. Extension occurs into the pelvis and throughout the pyramids, ultimately involving the cortex.