XII. Studies on biogenesis

The question of the origin of Bacteria and Torulœ lies so deeply at the root of some of the most important problems, not only of biology, but of pathology and practical therapeutics, that I make no apology for bringing forward the fruits of another investigation on the subject. The main question in controversy is whether these organisms originate de novo in the media where they grow, or whether they spring, like higher beings, from germs or parents like themselves.