The Cholera Germ

A Calcutta letter Htf '. There is good reason to believe tliat the visit to Calcutta of the Germán cholera commisslon has been fruitful of a very important disoovery. The in vestigations mude by the commission in Egy pt last year had already indicated the existence in all trne oases of cholera of a peculiar microscopio parasite, or baeillus, as it is termed In medical langoagth In all cases which came undur their examination, Dr. Kuch and lus colleagues observed these parasites in great numbcr, both in the intestines of the persons who had died of cholera and in the dejecta of cholera patients. The same parasites were uniformly found in all cholera cases examined in India. Moreover, although loolied for with minutenesa and care, no parasite corre9ponding to thein could be found in eonncction with other diseasiis, such as dysentcry and di irrhea, which have some resemblauco to cholera. The fact, thcrefore, of the close relation betweon the parasite and the disease of cholera would seem tobe ilaced beyond a doubt The coincidence would not ín iiself, however, as is obvious, warrant us In regarding the parasite as tlie cause of the malady; it may bethe consequence. From a ftirther discovery made by the commission in Calcutta, there is no reason to believe that the relation of parasite to the disease is one of cause; in short, that the parásito is the longsought-for cholera germ. While the commission was in Calcutta a sporadic outbrcak of cholera of great intensity occurred in the native quarter of the town, in the neighborhood of a dirty tank or pond. On examining the water in this pond Dr. Koch and nis colleagues discovered to their joy that it swarmed with the parasite which they had hltherto failed to find outside the human subject. Tlie water had been used, accorJIng to Indian habits, both for diinking and bathlng purposes by the pcople among whom the outbreak bad ocuncd. It was further observed thatus the outbreak subsided coiucidently the water became clear nf UvO -' ¦ Here was a great step in the furtherance f the inquiry as to the eüolojry of cholra. Another step, and the artificial propgation of the di.sease by means of the )arasite successfully accomplished, the ommission could havereported toPrince iismarek the completion of one of the most important discoveries ever made in medical science. But the last link com)leting the chain ofevidencehasyet to be orged. All theattemptsof Dr. Koch and lis colleagues to artificially propágate cliolera by means of the parasite, whether bund in the water or in the human subect, have been without sv.ccess. Many experiments have been made with a view o reproduce the disease by inoculation in animáis, but all have failed. Matter containing the parasite lias been mingled with the föod of mice, safe. aud dogs, but their lealtli hasapparently not been disturbed. l'he nrgument from analogy meanwhile joes strongly to show that in a parasite which a pair of Germán spectacles has revealed the cholera germ has at length yiekled up the dark mystery of existence. To Dr. Koch t feil some years ago to discover the parasite, or bacillus, which causes the disease of splenetic fever in aumals, and later to make tbc still more important discovery that tubercular consumption wasalso caused by a bacillus peculiar to it. Other investigations have further traced to a parasite the malady among fowlsknown as "chicken cholera," while there is strong reason to believe that the malaria associated witli the Roman campagna is alsoof a parasite origin. These cases leadto the belief that the true exciting c iiise of cholera has been fonnd in the paiasite di.-covered by the commission.