Then it was alleged that the entozoa, the worms found in the bodies of animals, were self-produced, without eggs, until the microscope discovered that one could lay 60,000 eggs.

Strauss, however, adhered to the idea that as the tapeworm, as he supposed, was self-produced, so man was originated by the primeval slime.

So also Professor Vogt, and M.Tremaux develop their animals from the land, and the latter accounts for their various qualities from the various qualities of their respective birthplaces, the crop being conditioned by the soil.

But Mr.Darwin derives all his organisms from the sea.
Electricity in its galvanic form was for a while the agent to fire the earthly or marine mud with the vital spark; and Mr.Crosse's experiments were supposed instances of the creation of acarii or mites in the battery bath, until it was found that the bath contained eggs and the electricity only hatched them.

Some English evolutionists still adhere to the theory of Spontaneous Generation, but the leading Germans deny any instance of it being known.