On the Metamorphosis of the Filaria Sanguinis Hominis in Mosquitoes, Especially with Reference to Its Metamorphosis in the Anopheles Rossii and Other Mosquitoes of the Anopheles Genus *This paper was read at the recent meeting of the British Medical Association.—Ed., I. M. G.

now, prevented the confirmation of Manson's discovery, lie was able to prove that in a certain species of the culex genus of mosquito (Culex Ciliaris. Linn.) the metamorphosis of the filaria required seventy to twenty days for its accomplishment. The important difference between his results and those of Dr. Manson is, that whereas Manson stated that only seven days were required for the metamorphosis of the filaria in the mosquito, Bancroft found that in his mosquitoes more than double that time was necessary; and he comes to the conclusion, therefore, that Manson must have been in error in his estimate of