254 THE MONTESSORI METHOD
they have come from real objective observation and from logical thought. These are simple things, but rarely found in one man.
Does it not seem strange, for instance, that after the discovery by Laveran of the malarial parasite which invades the red blood-corpuscles, we did not, in spite of the fact that we know the blood system to be a system of closed vessels, even so much as suspect the possibility that a stinging insect might inoculate us with the parasite ? Instead, the theory that the evil emanated from low ground, that it was carried by the African winds, or that it was due to dampness, was given credence. Yet these were vague ideas, while the parasite was a definite biological specimen.
When the discovery of the malarial mosquito came to complete logically the discovery of Laveran, this seemed marvellous, stupefying. Yet we know in biology that the reproduction of molecular vegetable bodies is by scission with alternate sporation, and that of molecular animals is by scission with alternate conjunction. That is, after a certain period in which the primitive cell has divided and sub-divided into fresh cells, equal among themselves, there comes the formation of two diverse cells, one male and one female, which must unite to form a single cell capable of recommencing the cycle of reproduction by division. All this being known at the time of Laveran, and the malarial parasite being known to be a protozoon, it would have seemed logical to consider its segmentation in the stroma of the red corpuscle as the phase of scission and to await until the parasite gave place to the sexual forms, which must necessarily come in the phase succeeding scission. Instead, the division was looked upon as spore-formation, and neither Laveran, nor the numer-