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Notice of the Result of an Experimental Observation made re- 

 garding Equivocal Generation. By F. Schulze, Berlin. 



Since the question respecting generatio rtquivoca has at- 

 tracted the attention of naturalists, the development of livino- 

 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 necessar\ con- 

 dition for the primary formation of infusoria from decom|v;sin"- 

 organic matter, so that the mere circumstance of covering an in- 

 fusion 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 vegetable organisms ? And in this point of viev.- 

 new direct experiments were considered to be very desirable. 

 The difficulty to be overcome consisted in the necessity of beino- 

 assured, first, that at the beginning of the experiment there was 

 no animal or germ capable of development in the infusion ; 

 and secondly, that the air admitted contained nothing of the 

 kind. For this purpose I constructed the apparatus represented 

 in Plate I. fig'. 2. 



I filled a glass flask half full of distilled wate-, in which 1 

 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 vio- 

 lently, and thus all parts had reached a temperature of 212° 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. 

 Ey means of the boihng heat every thing living, and all germs 

 in the flask or in the tube'-, 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 during the summer, to that of 

 heat. At the same time I placed near it an open vessel, with 



