Page:The Zoologist, 3rd series, vol 2 (1878).djvu/160

138 instead of the more accepted signification of helmenthologists, "intermediate host." He then gave some account of the mosquito after feeding on human blood. The female mosquitos, having gorged themselves, repair near stagnaut water, and remain semi-torpid for a few days, digesting the blood and voiding gamboge-coloured fceces. They deposit their eggs, which float in sooty flakes, on the surface of the water. Soon these are hatched, aud the larvae become the familiar "jumpers" of stagnant pools. The produce of Filaria, he believed, is thus taken iuto the human system with the drinking water. Dr. Mauson's method of procuring mosquitos containing embryo Filariæ was to get a Chinaman, whose blood was previously ascertained to abound with Filariæ, to sleep in a mosquito house. In the morning the gorged mosquitos were caught, and duly examined under the microscope. He thus ascertained that the blood ingested by the mosquito from a man suffering from Filaria contains a larger proportion of Filariæ than an equal quantity of blood obtained by pricking the finger of the same man. On one slide of the latter lie counted under the microscope some twenty or thirty, in the former upwards of one hundred and twenty. He remarked that all embryos do not attain maturity; and dilated on the metamorphosis of the embryo, giving drawings of the different stages as observed by himself. He concluded by remarking that the Filaria, escaping into the water as the mosquito dies, is through the fluid-medium conveyed to man. Within him it pierces the tissues of the alimentary canal. Development and fecundation proceed apace; and finally the embryo Filariæ, met with in the blood, are discharged in successive swarms aud in countless numbers—the genetic cycle being thus completed.

Dr. Gobbold then read a paper of his own entitled "The Life-history of Filaria Bancrofti, as explained by the discourses of Wucherer, Lewis, Bancroft, Manson, Sonsino, and others." This was a critical paper intended to elucidate the literary history of the discoveries of various observers, which have at length led up to a tolerably complete knowledge of the essential facts concerning this remarkable parasite. According to Dr. Cobbold, the Filaria Bancrofti is the sexually mature state of certain microscopic worms, obtainable either directly or indirectly from the human blood. It gives rise to more or less well marked diseases of warm climates, and a certain stage of the growth and metamorphosis of the worm takes place through the medium of blood-suekiug insects. Dr. Cobbold concluded by offering some suggestions as to the best means of checking the ravages of these parasitic plagues; adding a notice of the various authors who have written on the subject.—