RACE: Among all the aboriginal peo ples, when suddenly ushered into the midst of artificial life consequent upon civilization,—and the same may be said of animals which the ingenuity of man has succeeded in bringing into captivity, —the disease is terribly fatal; one has but to look upon the record the Indian has left behind him, or to go down among the slums of the great cities, and see its ravages upon the negro race: or to visit the menageries and ask "What limits the captivity of animals?" to sec the vast destruction of this disease. in each instance it is the Great White Plague which stares him in the face: a veritable barrier to a sudden transition from a non-civilized into a civilized en vironment. So fatal is it to the black man of this country when living under the influence of city life that we believe this disease will play no little part in the solution of the race problem which confronts us.
Morbid Anatomy and Pathology. Scattered throughout an infected area are found small, non-vascular, cellular masses—tubercles of different sizes, the result of tissue reaction upon the invad ing bacilli and their toxins. The tubercles are composed of various cellu lar elements and tubercle bacilli, the former being derived from multiplica tion of the fixed connective-tissue cells of the part, from the endothelium of the blood-vessels, and from leucocytes which have migrated in large numbers to the point of attack. There is sometimes seen in the centre of a tubercle an im mense giant cell which fre quently contains bacilli; its increased size is supposed to be due to an abortive effort at reproduction with resulting in crease in size, owing to its failure of division.
In the alveoli of the lungs and the bronchial cavities of rabbits tubercles develop exclusively at the expense of the leucocytes, especially those large mono nuclear cells which arrive quickly at each focus of infection. They therefore contend that the fixed cells of the alveoli and the epithelial cells of the bronchial walls play absolutely no role in the histogenesis of the tubercles. Morel and Daloux (Archives de Mild. Exper., Mar., 1901).
As a result of nutritional failure, the centre of this mass which is farthest re moved from nourishment, the whole being a tissue of a low degree of vitality.
undergoes coagulation-necrosis; subse quent softening may occur, with break ing down; or the liquid portion may be absorbed and leave a caseous mass, which, in turn, may become impreg nated with lime-salts giving a calcareous deposit, while the whole may be capsu lated in a fibrous protecting envelope that the tissue-cells have thrown out to surround the focus of infection, thus making of it a foreign body (see colored plate). Should softening and ulceration into a bronchus take place, a cavity is formed, its size depending upon the ex tent of structure invaded. From the absorption of the toxins, the adjacent tissues to a tubercular process undergo inflammatory changes to greater or less degree, and in the lungs of phthisical patients broncho-pneumonic areas are commonly found surrounding foci of in fection.
As might be expected in a disease which may be either acute or chronic, localized or diffusely infiltrated through out a tissue, the morbid anatomy pre sents a diversity of lesions, but under lying these varied conditions there is but one and the same pathological proc ess. These naked-eye differences are dependent largely upon mechanical or physical conditions; upon location; the tissues involved; the rapidity of the process; the degree to which the tissue cells have been able to throw out their protective barriers of fibrous tissue; and the subsequent behavior of that fibrous tissue, whether it contracts, which is its natural tendency, with resulting distor tion or puckering of lung, or, if local ized, with the formation of a scar or the obliteration of a bronchus, producing dilatations, or bronchiectasy; or whether it becomes diffuse throughout a lung or lobe, giving the picture of fibroid phthisis. Thus a tubercular cavity and a tubercular ulcer are one and the same thing, their only difference being in con tour, and they both represent a tuber cular nodule in its later stage, minus its broken-down and softened centre. The ulcer may be considered a cavity divided in half.