Note 31 — PHILOSOPHY OF LIFE. (continued 3)

Schlegel appears to have believed in the theory of equivocal generation. But microscopic research and experiments forbid us any longer to believe that fermentative or putrefactive matter spontaneously gives birth to living creatures. Such matters do but furnish the necessary circumstances for hatching the germs or ova which are present in such immense numbers in the atmosphere. The doctrine of equivocal or spontaneous generation seems conclusively refuted by the experiment of Schulze, detailed in volume 23 of Jameson’s Journal. “I filled a glass flask half full with distilled water, in which I had mixed various vegetable and animal substances. I then closed it with a good cork, through which I passed two glass tubes, bent at right angles, the whole being air-tight. It was next placed in a sand-bath and heated until the water boiled violently, and thus all parts had reached a temperature of 212° Fahrenheit. While the watery vapor was escaping by the glass tubes, I fastened at each end an apparatus which chemists employ for collecting carbonic acid; that to the left was filled with sulphuric acid, and the other with a solution of potash. By means of the boiling heat, every thing living and all the germs in the flask or in the tubes were destroyed, and all access was cut off by the sulphuric acid on the one side, and by the potash on the other. I placed this easily-moved apparatus before my window, where it was exposed to the action of light, and also, as I performed my experiments in the summer, to that of heat. At the same time I placed near it an open vessel with the same substances that had been introduced into the flask, and also after having subjected them to a boiling temperature. In order now to renew the air constantly within the flask, I sucked with my mouth, several times a-day, the open end of the apparatus filled with solution of potash; by which process, the air entered my mouth from the flask, through the caustic liquid, and the atmospheric air from without entered the flask through the sulphuric acid. The air was, of course, not altered in its composition by passing through the sulphuric acid into the flask; but if sufficient time was allowed for the passage, all the portions of living matter, or of matter capable of becoming animated, were taken up by the sulphuric acid and destroyed. From the 28th of May until the early part of August, I continued uninterruptedly the renewal of the air in the flask, without being able, by the aid of a microscope, to perceive any living animal or vegetable substance, although, during the whole of the time, I made my observations almost daily on the edge of the liquid; and when at last I separated the different parts of the apparatus, I could not find in the whole liquid the slightest trace of Infusoria, Confervæ, or of Mold. But all the three presented themselves in a few days after I left the flask open. And the open vessel too, which I placed near the apparatus, contained on the following day, Vibriones and Monades, to which were soon added larger Polygastric Infusoria, and afterward, Rotatoria.”—Trans.