Show TUBERCULAR DISEASE F Important Experiments The following letter bv Erof sor Tyndall appeared in the mesi Saturday Sat-urday On the 24th of March 1882 an address very Berona public import was delivered by Dr Koch before the Physiological Society of Berlin It touches a question in which we are all at pieaent interested tdat of experimental ex-perimental physiology ard I may therefore he permitted to give some account of it in toe Times The address ad-dress a cDpy of which has been courteously cour-teously sent to me by its author is entitled The Etiology of Tubercular Dibeaae Koch firet made himself known by penetration skill and thoroughness tho-roughness of hid researches on the contagium of splenic layer By a process of inoculation and infection ne traced this terrible parasite through all its stages of development and through ita various modes or notion no-tion This masterly investigation caused the young physician tD be transferred from a modest country practice in the neighborhood of Breslau to the poet of government adviser in the Imperial Health Department De-partment of Berlin From this department has lately been iasued a most important series of investigations on the etiology of infective disorders Kochs last inquiry in-quiry deals with a disease which in point of mortality stands at the head of them all If he says the seriousness serious-ness of a malady be measured by tbe number of its victims then the most dreaded pests which bave hitherto ravaged the worldplague and cholera chol-era included must stand far behind the one now under consideration Koch makes the startling statement that oneseventh of the deaths oi the human race are due to tubercular i disease while fully onethird of those who die in active middle age are oar ried ofl by the same cause Prior to Koch it had been placed beyond all doubt that the disease was communicable communi-cable and the aim of the Berlin physician phy-sician has been to determine the precise character of the contagium which previous experiments on inoculation inoc-ulation 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 ex-amination and found in ail oases the tubercles infested with a minute rod shaped parasite which by means of a special dye he differentiated from the surrounding tissue It was he say in the highest degree impressive im-pressive to observe in the centre of I the tubercle cell the minute organism organ-ism which had created it Transferring Transfer-ring directly by inoculation the tuberoulous matter from diseased animals an-imals 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 contagium he cultivated his bacelli artificially for long periods of time and through many successive generations With a speck of matter for example from a tuberculous human Jung he infected in-fected a substance prepared after much trial by himself with the view of affording nutriment to the parasite para-site Here he permitted it to grow and multiply From this new generation I gen-eration 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 auccesiva cul tivations extending over half a year the purified bacilli were introduced into the c rculation of healthy animals ani-mals of various kinda In every case inoculation was followed by the reproduction re-production and spread of the parasite and the generation of the original disease Permit me to give a further though still brief andHketchyacooun of Kochs experiments Of six guinea pigs all in good health four were inoculated with bacilli derived I originally from a human lung which in fiftYJour days produced five successive suc-cessive generations Two of the six animals were not infected In everyone every-one of the infected cases the guinea pig sickened and lost flesh After thirty two days one of them died and after thirtyfive days the remaining five were killed and examined In he guinea pig that died end in the three remaining infected ones strongly pronounced tubercular disease dis-ease had set in Spleen liver and lungs were found filled with tubercles tuber-cles while io the two uninfected animals an-imals no trace of the disease was discovered dis-covered In a second experiment six out of eight guinea pigs were inoculated in-oculated with cultivated bacilli derived de-rived originally from the tuberculous lung of a monkey bred and rebred for ninetyfive days until eight generations gen-erations had been produced Everyone Every-one of these animals was attacked while the two uninfected guinea pigs remained perfectly healthy Similar experiments were made with cats rabbits rate mice and other animals ani-mals and without exception it was found that the injection of tbe parasite para-site into the animal system was followed fol-lowed by decidedand in most cases virulent tubercular disease In the cases thus far mentioned inoculation had been effected in the abdomen The place of inoculation was afterwards changed to the aqueous humor of the eye Three rabbits received each a speck of bacilli culture derived originally from a human lung affected with pneumonia Eightynine fdaya had been devoted to the culture of the or u = ganam The infected rabbits rapidly lost flesh and lter twentyfive dnye were killed and examined The lungs of every one of them wre found charged with suberoes Of three other rabbits one rHcnvttl nn injection of pure blood serum in the aqueous humor of the eye white the other two were infected in a similar way with the same serum containing contain-ing bacilli derived originally from a diseased lung and e tjected to nine tyone days cultivation After twen tyeight days the rabbits were killed The one which had received the injection in-jection of pure serum was found perfectly healthy while the lungs of the two others were found overspread over-spread with tubercles Other experiment are recorded in this admirable esaay from which tbe weightiest practical conclusions may be drawn Koch determines the limits of temperature between which the tubercle bacillus can develop and multiply The minimum temperature tempera-ture he finds to be 86 ° Fahrenheit and the maximum 101 He concludes con-cludes that unlike the bacillus an tllracis of splenic fever which can flourish freely outside the animal body in the temperate zone animal warmth is necessary for the propagation propaga-tion of the newlydiscovered organism organ-ism In a vast number of oases Koch has examined the matter expectorated ex-pectorated from the lunge of persona affected with pathigU and iound in it swarms of bacilli while in matter expectorated ex-pectorated from the lungs of persons not thus afflicted he has never found tbe organism The expectorated matter m the former cases was highly infective nor did drying destroy its virulenca Guinea pigs infected with expectorated matter which had been kept dry for two four and eight weeks respeotiyely were smitten with tubercular disease quite ag virulent as that produced by fresh expectoration Koch points to the grave danger of inhaling air in which particles of the dried sputa of consumptive patients mingles with dust of other kinds It would be mere impertinence on my part to draw the obvious moral from these experiment In no other conceivable way than that pursued by Koch could the true character of the most destructive malady by which humanity is now assailed be deter minea And however noisy the fanaticism of the moment may be the common sense of Englishmen will not in the long run permit it to enact cruelty in the name of tenderness tender-ness or to debar ua from the light and leading of such investigations a3 that which is here sn imperfectly described de-scribed |