iin
��SCIENCEk
��[VOL. r.. No. 1
��tablisti ill a dcQuite maiuiei' the spcdQc pnlho- genic power of a micro-organ iam, wbicli, by its preaence in the blood, tissues, or alimentary canal, miiy be supijoscd, o priori, to bear a cauaal relation to the disease with which it is associated.
This pi'Oof depends ii|>on the production of characteriatic morbid plienomena by inoculat- ing susceptible animals with 'pure cultures' of the parasitic inicro-ot^anism previously found under circumstances to justify the supposition that It bears an etiological relation to the dis- ease under investigation. This Rnal proof Koch haa attempted lo obtain with reference to the 30-called 'comma bacillus,' which, ac- cording to his observations, is constantly associated with epidemic cholera, and, ader numerous failures, claims finally to have suc- ceeded. In a late number of the Deutsche medioinisc/te toochetiiKlirift, he says, —
"The expttrinicnta of Riet«ch and Nicati have been lately repeated at the Imperial board of health; a pure caltivatloa being so far dilated, that the amount Injected contained scarcely a hundredth part of a drop ol the cultivation liquid. The liquid waa Injected iDto the duodenum without previously bind- ing the ductus choledochus. With few exceptions, the animals so treated died within a space of time eiteiiding from a day and a half to three days. The mucous membrane of the small intestine was red- dened: Its conteuls wi^re walerj, colorless, or slightly reddUh tinged, and at the same lime flaky. Comma bacilli vrere found In the contents of the iiitcsUiie In a pure cultivation and In extraordinary numbers, so that the same phenomena were visible here as are Men in the cholera Intestine in its fresh state. Owing to the small quantity of Infectious matter used for injection, the idea at a elniultaneous intoxi- cation from poisonous matters contained In the culti- vaiiun liquid used for Injection is excluded." ■
Id face of the previously reported failures lo produce cholera in the lower animals, we are disposed to receive liic proof now offered with some reserve, inasmuch as the injections seem to have been made thi-ough the walls of the abdomen directly into the iatestiue. This method has, no doubt, been adopted upon llie supposition that previous failures were due to destruction of the bacilli by the acid juices of the stomach when tbey have been introduced by the month. There is nothing improbable in this supposition; but, on the other hand, the possibility' that when the mateiial is in- jected directly into the intestine the puncture made may have been a serious complication auri aource of error, nt once suggests itself.
That micro-organisms closely i-esembliiig the ' comma bacillus ' are to be found in the healtliy
< giir/eil from Hie BrUl-A «ii,l(>;,ljvuTttiil uf S'oy. £i. ISS),
��human moutb, and in the dischai'gea of patients with other forms of intestinal fiux, cannot be doubted; but that these are identical with the ' comma bacillus ' cannot be established u|>on morphological grounds alone. If one ' comma bacillus ' in pure cultures produces cholera, and another having identical morphological characters does not, wo must udmit an essen- tial difference — physiological — which, if con- stant, must be considered a specilic character, equal in value to a constant difference in form or in color. If such difference ia not constant, it will at least establish a pathogenic variety of the ordinarily harmless organism. But this is not the state of the question as regards Kocli's ' comma bacillus: ' for in his aoawcr to I'rof.T, R, Lewis of the English army medical school, who asserts that a curved bacillus, identical with the ' comma bacillus,' is found in normal human saliva; and h) Professors Finklcr and Prior, who claim to find similar organisms in ilie discharges of patients with cholera nostras (sporadic cholera), — Dr. Koch shows very conclusively that the oi^anisms referred to are not identical with the ' comma bacillus.' aU though bearing some resemblance to it. This conclusion is based both upon appreciable mor- phological differences, and upon the different behavior of the organisms when cultivated upon gelatine.
Through the courtesy of Dr. Biilings of tho army, I have recently had an opportunity to study the morphology of the ' comma bacillus,' having had in my possession for several daya a slide sent by Kocli himself to the Army medical' museum. My laboratory assistant, Dr. A. 0. Abbott, has made for me a camera lucdda drawing, which, I think, fairly represents the organiam aa seen in this slide, and which i« reproduced in fig. 1. B^h separate cell was drawn under the camera lucida: but the field as a whole is an ideal one, as I desired to show in a single figure all of the forms found in the slide. As a matter of fact, the '• commas ' aa seen at a are by far the most numerous, ami are found clustered in groups and masses; while the characteristic spirilla, such as may be seen at the centre of the field at i, are comparatively scarce. Still, in view of the intermeiliate forms, as seen at c. I cannot doubt that we have here a pure culture of a single organism, and that this organism is in truth a spirillum, and not a bacillus. If one saw only such forms as we have delineated at e. there would be no hesitation in pronouncing them bacilli; and the name 'comma bacillus,' (Vom a mor- plioiogical stand-point, applies very well to tho prevHiling form, as seen iit ". It is
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