Repository: UIHistories Project: Board of Trustees Minutes - 1886 [PAGE 303]

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297 The most characteristic post mortem phenomenon is the rapid softening, decay and deliquescense of the body, the whole of which may be converted, in an hour or two after death, into a dirty fluid mass which the rotten skin is barely sufficient to hold together. This breaks at a touch, allowing the fluid contents to escape. I have now demonstrated by a great variety of cultures and experiments that a large percentage at least, and quite probably nearly all of the minute sperical granules abundant in the fluids of the body and alimentary canal of the diseased cabbage worm are genuine bacteria belonging to the genus Micrococcus. In form the micrococci of the cabbage worm are usually strictly spherical, although in the alimentary canal a patch will occasionally occur in which they are of a slightly oval outline. The micrococci of the fluids of the diseased larvae seen in the field of the microscope are mostly separate spheres, but a considerable percentage of them are attached in pairs, as if in process of division. Barely a short chain of four, six or eight may be seen. In the stomach they occur not infrequently in compact patches or zoogloea-like masses. In size the individuals vary from .5 i± to 1.25 /J. in diameter, the small forms being commonest in the blood and the larger in the stomach. Individual larvae differ, in fact, with respect to the size of their micrococci, in some the average of those found in the blood being not far from .75 n to 1 n, while in others they barely reach .5 <u Usually those of the stomach average 1 ^. The proof of the contagious character of this disease must be deTived in part from the phenomena of its appearance, progress, and local distribution and in part from experiments purposely made for its propagation. That this affection or one very similar to it attacks the cabbage worms of the old world is made likely by a chance remark in Curtis's " F a r m Insects," where, speaking of several larvae of an allied species, Pieris brassicce, he describes cases of disease and death, suddenly appearing among them, precisely like that of our common cabbage worm. In this country the disease seems to have been first noticed in the vicinity of Washington, in 1879, although little attention was paid to it, and its bacterial character was not then ascertained. In Bulletin 3, of the United States Entomological Commission, (pp. 69, 70), Dr. Eiley remarks, while discussing some experiments made with yeast on the cabbage worm: "An incident connected with these experiments which I made is, however, well worthy of being mentioned, because it shows how very easily single experiments may lead to false hopes and conclusions. A certain proportion of the last-named larvae—the proportions differing in the different lots treated—perished before or while transforming to the chrysalis state. They became flaccid and discolored, and after death were little more than a bag of black putrescent liquid. I should have at once concluded that the yeast remedy was a success, had I not experienced the very same kind of mortality in previous rearing of this larvae, and had I not, upon returning to the field from which the larvae in question were obtained, found a large proportion similarly dying there."