Aids to pathology.

  • Campbell, Harry (Physician)
Date:
[1910]
Catalogue details

Licence: In copyright

Credit: Aids to pathology. Source: Wellcome Collection.

Provider: This material has been provided by The University of Leeds Library. The original may be consulted at The University of Leeds Library.

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    221 Filaria Sanguinis Hominis.—The adult foiin of this womi_ IS known as the Filaria Bancrofti, and the em- bryonic form as the Filaria nocturna. Filaria Bancrofti.—This form is confined to the lym- phatics. The female is about 3^ inches long, the male only about half this size. Eeproduction is viviparous, the female discharging her embryos mto the lymph, by which they are carried mto the blood-stream by way of the thoracic duct. Ftlana Noctarna.—The snakeUlie embryo is about ^^A^^^^*^ breadth about the diameter of a red blood-corpuscle. The head is provided with a short spme, and a circlet of hooked lips. The organism is imprisoned within a long loose sac mside which It can be seen to wriggle, but from which it is powerless to escape, so long as it remains in its human host. The embryos are present in the surface bloodvessels durmg sleeping hours only—whence the name F noc- turna; when the patient awakes they gradually retire to the ungs and larger bloodvessels. The cause of this re- DJarkable periodicity is unknown. If a filarial patient changes his hours of sleep from night to day, the periodicity changes correspondingly. r j As these filarias cannot further develop in the human host, they probably soon die, unless they are removed to an intermechate host This latter is a species of mosquito {Culex fashgans), which swallows the filaria when sucking human blood. In the mosquito's stomach the embryo escapes from the sac which has hitherto enclosed It and bores its way through to the thoracic muscles, where it comes to rest. By about four weeks' time it has grown considerably and then, resuming its travels, it reaches the proboscis, and returns to another human hos when the insect stmgs. It now passes to the lymphatics where it matures into the Filaria Bancrofti. The sexes then come together, and the yoimg are born rilanasis.--In the large majority of cases the presence of filanae m the human body gives rise to no obvious TT^r:- .1 ^«T-.y. however, the mature worm nay b ock the lymphatics, or the female may dischargT instead of embryos, unhatched ova which are large enough