Page:Tropical Diseases.djvu/49

i] fed in Rome on patients suffering from tertian malaria were forwarded in suitable cages to the London School of Tropical Medicine, and on their arrival were set to bite my son, the late Dr. P. Thurburn Manson, and Mr. George Warren. Shortly afterwards both of these gentlemen, neither of whom had been abroad or otherwise exposed to malarial influences, developed characteristic malarial fever, and malarial parasites were found in abundance in their blood both at that time and on the occurrence of the several relapses of malarial fever from which they subsequently suffered.

The mosquito-malaria theory has now, therefore, passed from the region of conjecture into that of fact.

In the lumen of the stomach: travelling vermicule stage.—When crescent-containing blood has been ingested by certain species of mosquito belonging to the Anophelinae, those crescents that are mature, and that are not obsolescent, are transformed into the two types of sphere already described—hyaline and granular; that is, male and female. The hyaline spheres then emit their filaments or microgametes, which, breaking away, approach and seek energetically by butting and boring to enter the granular spheres. At one point on the surface of each of the granular spheres a minute papilla is projected to meet, as it were, a corresponding attacking microgamete. At this point one of the latter contrives to enter, and, after momentarily causing considerable perturbation in the contents of the sphere, comes to rest and vanishes from view. Although the granular sphere may be subsequently energetically attacked, no second microgamete can effect an entrance. For a short time after this act of impregnation the granular sphere or