68 



DE. BASTTAN ON THE 



riment was made. I ascertained first of all, therefore, that the 

 fluids destined to be employed under certain definite conditions 

 as nourishing fluids were capable of acting efBciently as such, and 

 that under those particular conditions they never of themselves 

 behaved in such a manner as to make it possible to think tliat a 

 de novo production of living matter would occur therein. This 

 source of doubt being' eliminated, one could watch the efi'ects of 

 inoculating such fluids with living Bacteria and of subsequently 

 heating the mixture to different degrees, and draw tolerably safe 

 conclusions therefrom. Without such a precaution it is obvious 

 that, in the present state of this question, great mistakes might 

 be made, since efi'ects possibly due to the germinality of the fluids 

 as such might be attributed to a supposed survival of the germs 

 which had been heated in the inoculated fluids. I feel by no means 

 sure that some of the recent investigators working in Prof Cohn's 

 laboratory have been quite so mindfal of this point as they should 

 have been. 



I believe my experiments to have shown that a temperature 

 of 140° F. (60° C.) is destructive to Bacteria, Yibriones, Torulse, 

 and their germs in a neutral saline solution, and that the same 

 temperature is also destructive to Bacteria, Vibriones, and their 

 germs both in a neutral hay-infusion and in an acid turnip-infu- 

 sion. Even if we allowed the opposite interpretation to stand 

 in regard to those cases with the organic infusions in which there 

 was some room for doubt, we should still have to raise the death- 

 point only to 158° F. (70° C), and this, too, when the exposure 

 to such a temperature had only been prolonged for five minutes. 



Not the least countenance was given to M. Pasteur's notion 

 that Bacteria- and Vibrio-germs could resist a higher temperature 

 in neutral than they could in acid fluids. If there was any diff'e- 

 rence as between neutral hay- and acid turnip-infusion, it seemed 

 slightly in the other direction. 



These experiments were supposed to hold good, as I pointed 

 out at the time, for " germs " as well as for the parent organisms*. 

 The nourishing media were inoculated with a fluid in which Bac- 

 teria and Yibriones were multiplying rapidly, so that we had a 

 right to infer that they were multiplying in their accustomed 

 manner. I then said, " These experiments seem to show, there- 

 fore, that even if Bacteria do multiply by means of invisible gem- 

 mules, as well as by the known process of fission, such invisible 



* Proceed, of Royal Soc. vol. xxi. p. 227. 



