68 



NOTICE OF THE RESULT OF AN EXPERIMENTAL OBSERVATION MADR 

 REGARDING EQUIVOCAL GENERATION. * 



By F. Schulze of Berlin. 



SINCE the question respecting generatio aquivoca has attracted the 

 attention of naturalists, the developement of living organisms has 

 never been observed in vessels from which all air had been expelled by 

 boiling, and which had been hermetically sealed. The access of air 

 has been regarded as a necessary condition for the primary formation 

 of Infusoria from decomposing organic matter, so that the mere circum- 

 stance of covering an infusion with a stratum of oil, removed that 

 condition. But the question still remained undecided, If the access of 

 atmospheric air, light, and heat to infundirten substances included of 

 itself all the conditions for the primary formation of animal or of vege- 

 table organisms ? And, in this point of view new direct experiments 

 were considered to be very desirable. The difficulty to be overcome, 

 consisted in the necessity of being assured, first, that at the beginning 

 of the experiments there was no animal germ capable of developement 

 in the infusion ; and secondly, that the air admitted contained nothing 

 of the kind. 



I filled a glass flask half full of distilled water, in which I mixed 

 various animal and vegetable 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 tem- 

 perature of 21 2 F. While the watery vapour 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 concen- 

 trated sulphuric acid, and the other with a solution of potash. By 

 means of the boiling heat everything living, and all 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, were it was exposed to 

 the action of light* and also, as I performed my experiments during 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 constantly the air within the flask, I sucked with my 

 mouth, several times a day, the open end of the apparatus filled with 



* From Jameson's Journal, Vol. 23. 



