The possibility that the malaria plasmodia and especially Plasmodium falciparum may at times reproduce by binary fission during their early development within the red blood cells has recently been offered as an explanation for the presence of multiple infections of these cells in many cases of malaria. The finding of numerous erythrocytes harboring two, three and four young ring forms in a blood smear which also contains thousands of erythrocytes unparasitized is known to be fairly common. It is also quite simple to demonstrate ring forms in estivo-autumnal smears possessing two chromatin dots, some of which are opposite each other in the ring, some closer together, and still others which appear juxtaposed but are distinctly separate. The common occurrence of such forms, particularly in estivo-autumnal blood films, apparently obscured the significance of their presence for many years.
Craig as far back as 1905 called attention to these forms in the three common species of malaria and interpreted them as being conjugating forms, a view which he no longer holds.