When I am called upon to treat a patient suffering from an obstruction of the bronchial tubes occasioned by mucus, which is frequently thick and opaque and puriform--an obstruction extending to the delicate bronchial ramification, and causing oppression more frequently than cough, I turn my thoughts at once to _Bacillinum_. _Bacillinum_ is a drug for old people, or, at any rate, for those whose lungs are old; for those chronically catarrhal, or whose pulmonary circulation is enfeebled without regard to the age of the subject; for those who have dyspnoea, and who cough with difficulty from inaction of the respiratory ducts; for the humid asthmatic, the bronchorrheal, who feel suffocated at night; and, finally, for those who, after taking cold, are straightway attacked with pulmonary congestion. Here, I believe, is the exact sphere of action of _Bacillinum_ as a homoeopathic remedy. _Bacillinum_ has been stigmatized as an unstable product. I consider this reproach ill-founded. _Bacillinum_ is no more unstable than _Psorinum_, which is an approved remedy in Homoeopathy. Typical tuberculous lungs contain practically almost invariable elements. Do not the microbes produced by cultivation and the animal extracts show any variation in quality, and do they not change in the long run? Like most homoeopathists who have made use of _Bacillinum_, I think it is best given in the high dilutions and at long intervals. Dr. J. Compton Burnett and Van der Berghe recommended the higher potencies--the 1000th, 100,000, etc., whereas I content myself with the 30th, which satisfies every requirement. As regards the intervals which must elapse between the doses, certain writers recommend from one to two weeks. In acute cases I generally give six globules of _Bacillinum_ 30th every two or three days; and in chronic cases of tuberculosis, etc., one dose about twice a week. We are no longer permitted to include in the same description the tuberculosis of birds and that of mammals. Although the two bacilli, as far as form and color are concerned, are absolutely identical, the evolution of the two forms of tuberculosis presents characteristics so different that we are forced to study them separately. At this day the debate is a question of words, and experts discuss whether there are two distinct genera or merely two different species.