The rapid increase in the quantity of the remedy applied in the course of time is something that has no parallel. Koch gives an explanation, but leaves it to the future to be confirmed. We have no previous instance in case that his explanation should prove correct. Reasoning from analogous application of our remedy, we are led to assume that _smaller_ quantities of the substance would suffice to cause mortification of the remaining tuberculous tissue. Koch on the other hand uses larger and larger doses to reach a result. He admits inurement to the remedy within certain limits only. Koch has made a difference between pulmonary consumptives and those suffering from tuberculosis of the bones and joints, etc. He was able to inject larger quantities in the latter than the former, for the quantity injected in the case of pulmonary consumptives was .001 ccm.; in other tuberculous cases .01 ccm. Koch selected pulmonary consumptives for his experiments, whose sputum contained tubercle bacilli, so as to make no error in the diagnosis, and to ascertain by killing the bacilli contained in the sputum, whether the diseased tend toward restoration. As the remedy does not kill the bacilli, so a diminution of the bacilli can only be obtained in that manner, that the tissue of the lungs undergoes certain changes, which cause its properties to be such, that the bacilli are no longer able to exist or propagate in them. Then a so-called immunity results which we know of in other similar diseases. We know that anyone who has had the measles or scarlet fever rarely is again attacked by the same, as a rule he is permanently proof against them. In the same way as vaccination protects from small pox, an injection of Koch's remedy acts against pulmonary consumption. Koch makes a cautious statement: "On the other hand it is possible, from analogy with other infectious diseases that those who are once cured become permanently exempt." Koch reaches this result, that beginning phthisis can with certainty be cured with his remedy. On the other hand, advanced consumptives, in whose lungs large cavities already exist, may possibly be improved but can not be cured. However he provokes the idea, that perhaps his method of treatment together with a surgical operation, that removes all gangrenous matter from the lungs, may yet have beneficial results in the end. The idea is not entirely new to treat lung diseases with the aid of surgery; unfortunately the operations have heretofore been thought too risky. Perhaps we will now have a new branch in operative technic, surgery of the lungs. Koch advises to conduct this lung surgery after the manner of operating empyema. This is an operation performed in the case of suppurative pleurisy to remove the pus from the pleural cavity. This operation has been successfully carried out for a long time.