Note 3 — Chapter XI

Every reader of physiological works knows how easy it would be to multiply examples of this kind to any extent. Thus it is held by physiologists, that the sporules of fungi are universally diffused through the atmosphere, ready to vegetate whenever an opportunity presents itself: and that a single individual produces not less than ten millions of germs. It is held also that innumerable seeds of plants still capable of vegetation, lie in strata far below the earth's surface, finding the occasion to vegetate only by the rarest and most exceptional occurrences.—Carpenter, Manual of Physiology. 1851, Art. 44.