Page:Popular Science Monthly Volume 58.djvu/585

Rh the smaller animals. Upon this question, Swammerdam took a positive stand: he ranged himself on the side of the more scientific naturalists against the spontaneous origin of life. In reference to this matter he says:

"In attentively examining the development of insects, of animals with blood, and vegetables, one recognizes that all these beings grow and develop according to one law, and one feels how false is the opinion that attributes to fortuitous causes such regular and constant effects."

In Leeuwenhoek we find a composed and better balanced man. Blessed with a vigorous constitution, he lived ninety-one years, and worked to the end of his life, lie was born in 1632, four years after Malpighi and five before Swammerdam; they were, therefore, strictly speaking, contemporaries, lie stands in contrast with the other men in being self-taught: he did not have the advantage of a university training, and apparently never had a master in scientific studies. This lack of systematic training shows in the desultory character of his extensive observations. Impelled by the same gift of genius that drove