On filaria / by Joseph Bancroft.

  • Bancroft, Joseph, 1836-1894.
Date:
[between 1880 and 1889?]
Catalogue details

Licence: Public Domain Mark

Credit: On filaria / by Joseph Bancroft. 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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    g The stomoxys-fly, distended with blood, it is not difficult to capture on sunny walls. It may be distinguished from the common house-fly by the set of its wings, more divergent posteriorly, and lying with their tips resting on the wall. When captured* the sharp penetrating beak at once confirms its generic title. These flies are a great annoyance to horses in summer, gorging themselves with their blood, but I never found filariai taken up, except in the instance referred to, and then I had seen the fly feed on the dog. Dogs clean themselves of fleas and lice by biting, and so probably acquire the parasite; they frequently also snap at flies. Feeding experiments with various insects, containing blood, are however wanting, to trace the life history of the parasite; and from careful scrutiny, knowledge may be gained that would be of the greatest help in understanding what is wanted to arrive at the history of the human filaria. The embryo of F. immitis has no sheath, and is more active than the embryo of F. sanguinis hominis. In dissecting dogs known to have embryos in their blood, the portal circulation should be searched, in case the parent worms, not being found in the heart, are obstructed in their progress by the capillaries of the liver. When F. immitis is extracted from the heart, and placed in a vessel of blood or blood-serum, it writhes about with a slow motion, and as the coils rise above the level of the liquid, they appear pure white, as if greasy. A dead or injured worm rapidly becomes stained red. The worms have much rigidity while alive, and at times cause the death of their bearer, by rupture of the ventricle when hunting. There is no history of the filaria of the dog living in the human subject. I have examined the blood of many dogs belonging to the aborigines of this colony, but failed to find the parasite.* It has yet to be deter- mined if the embryos of F. immitis observe the periodicity in activity, shown by Manson to obtain in F. sanguinis hominis. In the sheaths of the tendons and burses, about the knee joint of the great kangaroo, there are often found worms as large as those in the dog, but not of such rigid texture. They are easily seen when the hind-quarters are skinned. The embryos of this worm never, so far as I have examined, enter the blood-vessels, but are plentiful in the synovial secretions of the bursse inhabited. How the embryos are transferred from their resting place is not known ; but I would expect that the mosquito, probably the large grey sort, has the power of pene- trating into the bursa? with its piercer. The ease with which the mosquito penetrates our trousers when tight over the knee, would indicate the possibility of this being the case, as the kangaroo sits with the integuments tense over the knee joint. The parasitic fly, that lives among the hair of the kangaroo, may play some part in the life history of this worm. None of the smaller species of kangai^oo in this neighbourhood have any worms near the knee. * Since found in the blood of blackfellows' dogs, June 1889.