A case of filaria sanguinis hominis nocturna / by Charles Williams.

  • Williams, Charles, 1827-1907.
Date:
1893
Catalogue details

Licence: Public Domain Mark

Credit: A case of filaria sanguinis hominis nocturna / by Charles Williams. 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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    by chilling, the haemoglobin leaves the red corpuscles, and is diffused through the plasma, which in consequence becomes thick and viscid ; and that the gastric secretions in the stomach of the mosquito act on the haemoglobin exactly in the same way, and so bring about the necessary thickening of the blood which provides a mechanical condition that enables the filaria to quit its sheath. In other words, the thickened plasma offers a resis- tance to the sheath, whilst the filaria is making vigorous efforts to burst through, which at last it accomplishes. It is not improbable that the gastric secretion may also act in softening the sheath. After the loss of the covering, and by careful watching of the head, Dr. Manson has made out that the animal is pro- vided with a thick stumpy tongue or proboscis (a, Fig i), which is alternately covered and uncovered (Fig 2) by a six- lipped retractile prepuce (b, Fig. 1), that occasionally a short and extremely delicate filament (c, Fig. 1) is shot out and'retracted from the tip of this tongue-like organ. He considers the filament (c) is a feeler of some sort; the tongue (a) a borer; and the lipped prepuce (b) a dilator and hold-fast, and that they operate in this manner: When a weak poinr|in*the tissues of the mosquito has been discovered by the sense filament, the tongue is thrust out and a shallow pit formed ; the tongue is then withdrawn, the prepuce being slipped over it. The prepuce- covered tongue is then thrust into the shallow pit, and the FIC 2