352 THE BEGINNINGS OF LIFE. 



five minutes after they had been hermetically sealed, by 

 the mere application of one of my fingers., which had 

 been dipped in cold water, to a portion of the glass 

 above the level of the fluid. The water-hammer effect 

 was also very obvious., in those which were tested in 

 this fashion. 



I believe that an almost perfect vacuum can be 

 produced in this way. During the first violent 

 ebullition the air is driven out of the flask by the fluid, 

 and as ebullition is continuously kept up after this till 

 the flask is hermetically sealed, there is always an 

 outpouring of heated vapour, and no opportunity for 

 re-ingress of air. But even, if in any given case, the 

 vacuum should not prove to be absolute, it does not 

 seem to me that there would be any material abate- 

 ment from the severity of the conditions which strict 

 experimentation would demand. If, on the one hand, 

 absolutely the whole of the air had not been expelled 

 from the flasks during the process of ebullition, what 

 remained would necessarily be mixed up with a very 

 much larger quantity of continually renewed steam, 

 and the effect would probably be that any living 

 things would be just as effectually and destructively 

 heated in this as if they were lodged in the boiling 

 solution itself; whilst if, on the other hand, the boiling 

 had been arrested for one or two seconds before the 

 complete closure of the almost capillary orifice at the 

 mouth of the flask, and any air had entered, it would 

 have had first to pass through the blow-pipe flame, and 



