Remarks on a fluke parasitic in the copper-head snake / by D. McAlpine.

  • McAlpine, Daniel, 1848-1932.
Date:
1891
Catalogue details

Licence: Public Domain Mark

Credit: Remarks on a fluke parasitic in the copper-head snake / by D. McAlpine. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    which is most frequented. Tliey seemed to ordinary inspection quite black, and as many of them were at least a quarter of an inch in length, there was no difficulty in seeing the oral and ventral suckers. Habits.—As the specimens were numerous and all alive, I had plenty of opportunities of observing their habits. They were seen to move along in the interior of the semi- transparent stomach at a comparatively rapid rate, by extending the body its full length, then fixing the head sucker and contracting to the fullest extent. In this way a continuous progressive movement was kept up. The same movement was seen on placing them in a little water in a watch glass, from which they tried to escape, and the amount of altei'nate expansion and contraction displayed was considerable. They also sometimes moved to and fro in the water. Usually when taken from the body and placed in a little water, or water and glycerine, they discharged the dark-brown ova in successive jerks sufficient to discolour the water or mixture. Almost invariably when taken direct from the body, and placed in water on a slide under the microscope, they were observed to jerk out the ova with considerable force, from an opening adjacent to, and immediately behind the oral sucker. In its force and suddenness, the discharge seemed like a display of fireworks. In some instances, the brown ova were so completely ejected, as to render the body white-looking to the naked eye, while in others only a very partial dischai-ge took place. It is very instructive to observe the eggs passing out of the body in Indian file, and this can be done leisurely. I placed a specimen on a slide, and a cover-glass over it, so that when gently pressed, a.constant stream of ova flowed out, quicker or slower, according to the pressure, and as long as desired. The ova discharged so near the mouth orifice would frequently fill it, then they would be sucked in and suddenly thrown out and scattered in all directions. Another movement frequently observed under the microscope, was that of apparent feeding. Every now and again, what seemed a long neck-like portion of the body would be stretched forward and the mouth opened at the same time, then the body would contract and the mouth-opening close. They assumed all sorts of shapes and proportions in moving to and fro, well seen as they moved about on a moistened slide. In water they could remain alive for some time, for several hours at least.