The four cases quoted by Dr. Mersch (_Journal Belge d' Homéopathie_, November, 1894, January and May, 1895) are very instructive: The first is that of a member of the Dutch Parliament who had contracted a pneumonia which reached a chronic stage. While undergoing a relapse his expectoration assumed a rusty-red color, which color disappeared completely in three days on treatment with _Tuberculin_ 30th. The second case is that of a person who was seized, after an attack of measles, with broncho-pneumonia. On the fifth day Dr. Mersch prescribed _Tuberculin_ 6th. In a day or two the condition of the chest was completely altered. In the third case an old lady was likewise attacked with broncho-pneumonia, together with digestive troubles, and was for a long time in a serious state. After the lapse of a single night, which was a rather distressing one, under the action of the remedy the amelioration was great, and it was with difficulty that Dr. Mersch found a touch of bronchitis in the very place where the day before he had heard nothing but the tubular _souffle_. The prescription ran: _Tuberculin_ 6th, eight packets of ten globules each, one to be taken every two hours. Finally, in a fourth case, the patient was a lady of vigorous physique, and twenty-five years of age, who had capillary bronchitis, combined with the symptoms of angina pectoris. Dr. Mersch had once more had an opportunity of viewing with astonishment the rapidity with which the therapeutic action of _Tuberculin_ may be manifested in such cases. * * * * * _Bacillinum_ deserves study from two points of view, isopathically in the treatment of tuberculosis, homoeopathically in the treatment of affections of the respiratory organs without tuberculosis. To fully understand its action it is necessary to know with exactness its composition. Dr. J. Compton Burnett has christened it _Bacillinum_, because he recognized in its lower dilutions the presence of Koch's bacilli. As a matter of fact, _Bacillinum_ contains in its elements everything that a cavity of a tuberculous lung is capable of containing; that is to say, many other things besides Koch's bacillus. The bacillus of Koch is feebly pyogenetic, and the purulent contents of the cavities include pyogenetic staphylococci and streptococci, to say nothing of the organic products which play a large part in the production of the hectic fever of tuberculosis. It is a combination of toxins, then, which constitutes _Bacillinum_, and especially of toxins of a purulent nature. I lay stress upon this last fact, as it goes to sustain the opinion that I hold on the action of _Bacillinum_.