In such instances, the direct reception of the bacilli into the lymph-current is assumed rather than demonstrated from a knowledge of the possibilities of absorption and an appreciation of the conditions in the glands. That an actual growth of tubercles from the wall of the intestinal {104} lymphatics may take place has long been known, and Ponfick has recently discovered that tubercles may be found growing from the wall of the thoracic duct. The possibility of the direct admission into the lymph-current of the infective element in tuberculosis is thus apparent, and its indirect entrance into the blood-current is equally obvious. That the bacillus of tubercle may be directly received into the blood-current is likewise evident from the observations of Weigert, who found tubercles growing from the walls of the pulmonary blood-vessels, venous as well as arterial. This discovery of a tuberculosis of the blood-vessels was confirmed by Klebs, who had found a tuberculosis of the azygos veins. The occurrence of multiple miliary tubercles of the pulmonary veins, especially near the place of entrance of smaller branches, has been asserted by Mügge,[74] although appearances similar to those described by him may be met with, due simply to the agglomeration of white blood-corpuscles and their necrosis. Such a condition simulates very closely the miliary tubercle, but is usually analogous to the appearances figured by Virchow,[75] and described by him as one of the phenomena of coagulation. In his observation the white bodies were adherent to the red clots, and were with them drawn from the pulmonary artery. [Footnote 74: _Virchow's Archiv_, 1879, lxxvi. 243.] [Footnote 75: _Die Cellular Pathologie_, 4te Auflage, 1871, 184.] With the admission into the body, and the colonization of the tubercular bacilli, their effects may either be progressive until the death of the individual is occasioned, or, with the cessation of the growth of the bacilli or a possible modification of their noxious properties, recovery may ensue. The history of scrofulous glands, as well as that of circumscribed pulmonary inflammation in scrofulous persons, both presumably of a tuberculous nature, show that the effects of an invasion of the parasites may be overcome.