THE CAUSE OF CONSUMPTION.

Globe, Volume XXIV, Issue 2563, 26 June 1882, Page 3

THE CAUSE OF CONSUMPTION.

Professor Tyndall has communicated a letter to the “ Times,” in reference to an address before the Physiological Society of Berlin, by Dr. Koch, on “ The Etiology of Tubercular Disease.” Professor Tyndall says that Koch first made himself known by the penetration, skill, and thoroughness of bis researches on the contagion of splenic lever. By a process of inoculation and infection be traced this terrible parasite through all its stages of development and through its various modes of action. This masterly investigation cansed the young physician to be transferred from a modest country practice, in the neighborhood of Breslau, to the post of Government Adviser in the Imperial Health Department of Berlin, From this department has lately issued a moat important series of investigations on the etiology of infective disorders. Koch’s last inquiry deals with a disease which, in point of mortality, stands c.t the head of them all. If, he says, the seriousness of a malady be measnred by the number of its victims, then the most dreaded pests which have hitherto ravaged the world—plague and cholera included—must stand far behind the one now under consideration. Koch makes the startling statement that one seventh of the deaths of the human race are due to tubercular disease, while fully one-third of those who die in active middle ago are carried off by the same cause. Prior to Koch it had been placed beyond donbt that the disease was communicable j and the aim of the Berlin physician has been to determine the precise character of the 'contagion which previous experiments on inoculation and inhalation had proved to be capable of indefinite transfer and reproduction, He subjected the diseased organs of a great number of men and animals to microscopic examination, and found, in all cases, the tubercles infested with a minute, rod-shaped parasite, which, by means of a special dye, be differentiated from the surrounding tissue. It was, he says, in the highest degree impressive to observe in the centre of the tubercle cell the minute organism which had created it. Transferring directly, by inoculation, the tuberculous matter from diseased Animals to healthy ones, he in every instance reproduced the disease. To meet the objection that it was not the parasite itself, but some virus in which it was imbedded in the diseased organ, that was the real oontagiam, ho cultivated his bacilli artificially for long periods of time and through many successive generations. With a speck of matter, for example, from a tuberculous human lung, ho infected a substance prepared, after much trial, by himself, with the

view of affording nutriment to the parasite. Here he permitted it to grow and multiply. From this new generation he took a minute sample and infected therewith fresh nutritive matter, thus producing another brood, Generation after generation of bacilli were developed in this way, without the intervention of disease. At the end of the process, which sometimes embraced successive cultivations extending over half a year, the purified bacilli were introduced into the circulation of healthy animals of various kinds. In every case inoculation was followed by the reproduction and spread of the parasite and the generation of the original disease. Koch determines the limits of temperature between which the tubercle-bacillus can develop and multiply. The minimum temperature he finds to be eighty-six degrees Fahrenheit, and the maximum 104 degrees. Ho concludes that, unlike the bacillus anthracis of splenic fever, which can flourish freely outside the animal body in the temperate zone, animal warmth is necessary for the propagation of the newly-discovered organ* ism. In a vast number of cases Koch has examined the matter expectorated from the lungs of persons affected with phthisis and found in it swarms of bacilli, while in matter expectorated from the lungs of persons not thus afflicted he has never found the organism. The expectorated matter in the former oases was highly infective, nor did drying destroy its virulence. Guinea pigs infected with exi peotorated matter which has been kept dry for two, four, and eight weeks respectively, , were smitten with tubercular disease quite as virulent as that produced by fresh expectoraration. Koch points to the grave danger of i inhaling air in which particles of the dried sputa of consumptive patients mingles with dust of other kinds.