Page:Popular Science Monthly Volume 59.djvu/205

Rh vivax, every 48 hours. Another form, giving rise to a more malignant type of malaria, is Laverania malariæ, which probably sporulates every 48 hours. Tn some types of the disease it is supposed that two or more

The young sporozoites (a) penetrate red blood corpuscles and grow at the expense of the hæmaglobin (b—d). Spores (c—f) are finally formed and the growth products (melanin) are liberated. These spores, or merozoites, enter new blood cells and repeat the process (auto-infection). When taken into the stomach of the mosquito Anopheles, the parasites become much larger, some develop male gametes (o, p, q) on the Polymitus form {p); others, female gametes (r—u). These conjugate (v) in the stomach of Anopheles, and the copula (w) penetrates the epithelial lining of the stomach and ultimately lies suspended in the body cavity (x—zz). When mature, the parasite forms spores (A), which form, in turn, naked sporozoites (B). The sporozoites are liberated into the body cavity, and finally penetrate the salivary gland of the mosquito (C), from which they are emptied out with the fluid from the gland into the blood of a human host.

species may be present at the same time, and, sporulating at different intervals, may give rise to irregular attacks.

Until 1896, the life history of the parasite, as outlined above, was regarded as incomplete because of the perplexing form discovered in