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TABLE OF CONTENTS OF VOLUME FIRST.
Assistant Professor of Physical Diagnosis in the University of Penn-
Professor of Theory and Practice of Medicine in the Columbian Univer.
sity, Washington, D, C.
DISEASES OF THE LUNGS.
BY JAMES T. WHITTAKER, M.D.,
Etiology.—The bacillus tuberculosis, the one fixed fact in the pathology of the disease, is now universally regarded as the acknowledged centre about which all the phenomena of the disease must revolve. Thus, the etiology of tuberculosis is the life-history and habits of the tubercle bacillus, including the conditions most favorable or unfavorable for its reproduction and growth in the body; its symptomatology, the effect it produces in the body. The definite diagnosis is the recognition of the bacillus in the discharges or tissues, and the therapy the use of the agents which will destroy it, or will render the soil of its selection infertile for its growth. Whatever views, theories, or hypotheses will not fit in with this fact are relegated as obsolete lumber to chapters on the history of the disease.
Invasion by Inheritance. The first question in etiology in point of time and one of the first in importance is the question of heredity or hereditary transmission of the disease. The older writers felt no hesitation in assuming a direct transmission of tuberculosis from parent to child. The very fact that the offspring of tuberculous parents were most frequently affected with the disease was sufficient proof of the rôle of heredity. The question with them was merely a question of percentage. Statistics in this connection varied according to the range of ancestry or relationship included in the list. Thus, according to Williams, of one thousand and ten cases of the Brompton Hospital report, which included only parents, the influence of heredity gave an average of 24.4 per cent., while Pollock's one thousand and two hundred cases, which included parents, brothers, and sisters, furnished 30 per cent., Cotton's one thousand cases, with the same range, 36.7 per cent., and Fuller's three hundred and eighty-five cases, which embraced grandparents, uncles, and aunts, 59 per cent.
reports from the same source materially reduce these percentages in the case of direct hereditary predisposition. Thus, of one thousand cases accurately studied in this regard by C. Theodore Williams 2007 but one hundred and ten (i.e., 12 per cent.) had parents affected with the disease, while brothers and sisters were affected in the case of two hundred and twenty-four, a disproportion which at once subordinates the role of heredity to that of association with affected cases.
After Koch's discovery of the tubercle bacillus the possibility of hereditary transmission of tubercular diseases was denied by the adherents of the theory of parasitic origin. But recently there has been a growing belief with some workers on the subject that the old view founded on clinical evidence was right, and various hypotheses have been started to explain this on the bacillary theory. The most startling of these views is that propounded by Baumgarten, * who is of the opinion that a child may be born with the bacillus tuberculosis in some of its tissues, and that it
may remain inactive for years or throughout life. Firket som criticises very ably the evidence in favor of the hereditary transmission of tubercular disease. Some observers (Baumgarten, Landouzy and Martin) admit the possibility of a congenital tuberculosis, the actual occurrence of which has been rigorously proved by Johne in the fatus of a tubercular cow. Landouzy and Queyrato have also established the relative frequency of tuberculosis in infants. Such a transmission may be explained in one of two ways: (a) through the semen or ovum, or (b) through the placental circulation. The first view is, as yet, purely hypothetical, for one is not allowed to generalize from Johne's observation, who found in a small number of consumptives that the tubercle bacillus was present in the spermatic tubules and beneath the epithelium of the prostate without any appreciable disease of the organs. Further, Rohlfs has inoculated rabbits with semen from consumptives with uniformly negative results. However, admitting this possibility of inoculation of the ovum from the semen or maternal secretion, proof would be required that the development of the embryo would proceed regularly. Until such proof is forthcoming, a priori considerations are against it, not only from the behavior of other diseases, but, also, since Joline has pointed out that though uterine tuberculosis in the cow did not prevent conception, yet