If infection from tuberculous domestic animals in general does not appear to be frequent, it must by no means be under-rated. Perlsucht of cattle and the caseous changes in the lymph glands of pigs are of so frequent occurrence that they deserve close attention. If, now, we follow the tuberculous bacilli which have got into the lungs by inhalation, into the skin by wounds, into the intestinal canal by swallowing, in their further conduct in the body, we see that they often remain for a long time-sometimes even permanently-in the place of their first establishment. From herds' of epithelioid cells they form little knots which enclose giant cells, and regularly from the centre out, fall victims to coagulationnecrosis. The appearances which are conditioned upon the gradual growth of such a herd, and the regressive changes which always keep step with it, have been described in detail in a former section. The first sign of the spreading of the tuberculous process into the neighboring region is the formation of similar knots in the neighborhood of the primary herd. The way, also, in which the migration of the bacilli from the first herd to the place where the secondary knots arise, is to be conceived, I have also already suggested. The following appears to me to be the simplest explanation of this proceeding. The tuberculous bacilli, since they possess no motion of their own, can only be moved along by elements possessing the power of motion, or by currents of liquid. But since the tuberculous knots have no vasal2 and one cannot see how other liquids, which are in motion can get into the tuberculous herd and sweep away bacilli from them, nothing remains but the wandering cells, which according to experience, act the same part in other disease-producing bacteria, which those elements perform, that provide for the transport of the bacilli. The cell, laden with a bacillus only goes on until, under the influence of the parasite, it loses its power of motion. On the spot where the cell came to a stand-still a new tuberculous knot must arise. In this manner groups of tubercles form, which melt, perish, and cause destruction in the well-known manner. With the supposition that the wandering cells may be the bearers of the bacilli, we see in the most natural manner the connection with the farther excursions which the tuberculosis bacilli make in the body in almost all cases. When the wandering cell moves in the tissue-passages and must rely on its own power of motion, then the distance which it travels is only a short one and the newly arising infectious herd must lie in the neighborhood of the point of departure. But as soon as the wandering cells move in the lymph-vessel and the lymph-stream comes to their help in their movement, then they travel greater distances, as is seen not seldom, in the tubercles spreading themselves out in the course of the lymph-vessels. But very often then the tuberculous bacilli are swept away still farther in the lymph-vessels and led into the nearest lymphglands, where in like manner as in the first place of infection they call forth the formation of knots and caseous degeneration. The changes conditioned upon this in the gland-tissue appear usually to hinder a further progress of the bacilli by the way of lymph-passages. But by this no insurmountable barrier is placed in the way of the progress of the bacilli. They can, under special conditions, get into the stream of the blood. This happens when, as Ponfick has shown, the tuberculosis attacks the thoracic duct, and reaches the interior of the same; 1 Collection or clusters. 2 Outlet or inlet vessel. the tuberculous bacilli are then led direct from the lymph-stream into the bloodstream. * The relation is similar between the tuberculosis of animals, above all of perlsucht, and tuberculosis in man. These also must, on account of the identity of the parasites on which they are conditioned, be held to be identical with human tuberculosis in spite of the differences in the anatomical behavior and in their clinical course. It has, to be sure, been stated, especially with reference to perlsucht, that the transmission of this disease to man has not yet been certainly proved. On the other hand the following may be said: On account of the very slow development of the disease, the place and time of the infection and therewith the source of the same can no longer be confidently stated, when the first plain symptoms appear. On this account in the frequent inhalationtuberculosis the mode of infection can be determined in a scientific manner only in comparatively few cases. Still less will this be possible in the much rarer cases of intestinal tuberculosis arising from the use of flesh or milk of cattle suffering from perlsucht, because here the uncertainty is heightened by the easily possible confusion with other much more frequent kinds of infection. It is therefore very questionable whether ever a case of human tuberculosis can without criticism be attributed to the use of the meat or milk of tuberculous animals. But if one thinks, that to the most various sorts of animals (cats, rabbits, guinea pigs, field mice) by inoculation with masses of perlsucht and the pure cultures gained from them, a disease can be generated with the greatest regularity which anatomically is exactly like the disease caused by inoculation with tuberculous masses, and which kills the animals with the same certainty as the last, then it is not to be expected that man should be an exception to this disease-poison. If in the course of further investigations again a difference between the perlsucht and the tuberculous bacilli should show itself, which would compel us to consider the same as only near relations, we should even then have all cause to hold the perlsucht bacilli as suspicious in the highest degree. From the hygienic standpoint the same measures must be taken against it as against the infection through tuberculous bacilli, so long as it is not proved that man can bring perlsucht bacilli in contact with skin-wounds without danger, that he can inhale the same or bring their spores into his intestinal canal without becoming tuberculous. So far as is known to this department, the disease among cattle has not increased in number of cases in Rhode Island during the past year. There is, however, no probability that the number has decreased in any large measure, although the knowledge of the means by which the disease may be lessened or prevented, is much more largely disseminated than at any previous time. The Report upon Tuberculosis, a 38 page pamphlet, prepared by the Secretary by request, and presented to the General Assembly at the January Session of 1889, has been quite freely distributed throughout the State. The final pages of that report may very prop. erly be re-printed in this connection: CONCLUSIONS. A consideration of the opinions of eminent veterinarians presented in the foregoing pages, and the results of personal inquiry and personal observations, seem to warrant the following propositions : a. Tuberculosis is the most extensively distributed and most destructive disease now extant upon the earth. b. Mankind and the lower animals are alike the victims of the disease. C. Mankind and the brute creation are alike more largely susceptible to, and proportionately more frequently the victims of, the disease, under the circumstances of advanced civilization. d. Tuberculosis is communicable from animal to animal and from the lower animals to mankind, and vice versa, under all conditions of existence. e. The disease is communicable from animals to man usually by means of uncooked or partially cooked flesh and milk; from man to animals by the ingestion of the sputum of a consumptive person. f. Tuberculosis is communicated from one animal to another by means of the ingestion of milk, or of the sputum or expectoration of an animal so diseased, or may be transmitted by heredity, and possibly by the inhalation of the breath of an animal affected with pulmonary tuberculosis. g. A tuberculous animal, if introduced into a herd of healthy cattle, will often affect the whole herd sooner or later. h. A healthy animal introduced into a herd of tuberculous cattle, will, usually, sooner or later, become affected with the same disease. i. Tuberculosis may therefore be hereditary or infectious. The progeny of animals, so diseased, will sometimes show an incipient development at the time of birth, and at varying periods of a few weeks or months thereafter. j. The specific cause or agent, (the bacillus tuberculosis), may remain dormant in the progeny of tuberculous animals for several years under circumstances and surroundings favorable to the best health and most vigorous functional activity of the animal. k. Close confinement in a very warm atmosphere, imperfect ventilation, lack of proper exercise in the open air, too early and too frequent breeding, the interbreeding of animals hereditarily predisposed, and too free use of stimulating or fermenting food, the forcing methods for the greatest production of milk, deprivation of a sufficient amount of healthful food; in short, whatever lowers the tone of the vital powers, promotes the development of tuberculosis. 1. Usually the first noticeable symptoms are, a short dry cough, (in occasional cases no cough occurs untill the disease has reached an advanced stage), a shortness of breathing upon being hurried, tendency to premature birth or early dropping of offspring, swelling of the joints attended with lameness, nymphomania in cows; but an early positive diagnosis is in many cases impracticable in the living animal. m. A positive diagnosis can be reached in the more advanced stages of the disease, when tubercular matter can be obtained and the inoculation of healthy animals therewith be resorted to. n. In the later stages the rational symptoms, loss of flesh, unthriftiness of appearance, diminution and thinning of the milk, difficult breathing attended with cough, and especially if there is present any enlargement or tenderness of the udder, will declare the disease; and the milk of such animals can not be used with safety. 0. Upon the appearance of the earliest symptoms of tuberculosis every cattle owner, for the public safety and his personal interest, should secure an examination of the animal by a competent veterinarian, and if the case is suspicious only, the animal should be isolated until a positive diagnosis can be made. p. When an animal has been found affected with confirmed tuberculosis, public safety requires that such animal should be destroyed, and that those animals exposed to its infection, should be quarantined and watched. q. The presence of tuberculosis among the bovine animals of Rhode Island, is a menace to the public health and prosperity of the State, and the General Assembly should provide compensation for the owners of such cattle as are destroyed to prevent the spread of such disease, not only among cattle but among the citizens of the State. r. Facts already known seem to warrant the assumption, that not less than five in every one hundred of the milch cows in the State, above five years of age, are affected in some degree with tuberculosis. 8. The disease is much less liable to be communicated during the earlier stages, either by the milk or otherwise, the liability at all times depending largely upon the part of the body in which or upon which the tubercles are situated. t. Immunity from the infection of tuberculosis through the use of flesh as food, may be secured by thorough cooking; and the milk of cows, by a half hour's boiling, may also be made safe for use as food. Respectfully submitted, CHAS. H. FISHER, Secretary. |