EXPERIMENTAL CONDITIONS 61 



developing organisms showing that 100 C. for 

 one minute has been sufficient to kill them. 



Again, where Moulds (Penicillium) have devel- 

 oped freely, in one of these test flasks, and have 

 produced at the surface crowds of acrospores, I 

 have well shaken the contents of such a flask and 

 have then inoculated some minims of the solution 

 into another sterilised flask containing some of the 

 fresh test solution, and have boiled it for five min- 

 utes, and in another even only for one minute. I 

 have two such flasks now before me, and after 

 several months they still show no sign whatever 

 of any developing Mould. Even one minute's ex- 

 posure to a temperature of 100 C. has therefore 

 been sufficient to kill the acrospores of these 

 Moulds that have been developed in and from 

 tubes previously heated to 130 or 135 C. 1 



In regard to the Plates, I may say further, that 

 they begin with organisms taken from tubes that 

 had been heated to 125 C., and go on to organ- 



1 This is entirely in accord with previous knowledge. De 

 Barry, for instance, speaking of the death-point of the spores 

 of Fungi in water or watery vapour, says : " It has not been 

 shown that any can under these circumstances survive a tem- 

 perature of 100 C." (Fungi, Mycetozoa, and Bacteria, 

 Translation, 1887, p. 347). 



