226 



Prof. H. C. Bastian on the Heat 



[Mar. 20, 



observers who have supposed they have found Bacteria surviving after 

 boiling have made the mistake which I should have done at one time, and, 

 in fact, have confused the Brownian movements with true living move- 

 ments." Some eminent biologists do not now (in reference to the experi- 

 ments cited in my lasb communication) suggest that the organisms found 

 in the infusions were dead and had been there before the fluids were 

 boiled : they express doubts concerning that which seems formerly to 

 have been regarded as established, and now wish for evidence to show that 

 the germs of Bacteria and Vibriones are killed in a boiling infusion of 

 hay or turnip, as they have been proved to be in " Pasteur's Solution " 

 and in solutions containing ammonic tartrate and sodic phosphate. 



With the view of removing this last source of doubt more effectually, 

 and also of refuting the unwarrantable* conclusion of M. Pasteur, to the 

 effect that the germs of Bacteria and Vibriones are not killed in neutral 

 or slightly alkaline fluids at a temperature of 212° P., I almost imme- 

 diately after the reading of my last communication commenced a fresh 

 series of experiments. 



Nearly two years ago, in my ' Modes of Origin of Lowest Organisms,' 

 I brought forward evidence to show that Bacteria, Vibriones, and their 

 supposed germs are killed at a temperature of 140° P. (60° C.) in neutral 

 or very faintly acid solutions containing ammonic tartrate and sodic phos- 

 phate, and also evidence tending to show that these living units were 

 killed in neutral infusions of hay and in acid infusions of turnip at the 

 same temperature. 



The crucial evidence adduced concerning the degree of heat destructive 

 to Bacteria, Vibriones, and their germs, in the saline solution, was of 

 this nature. The solution had been shown to be incapable of engendering 

 Bacteria and Vibriones (under all ordinary conditions) after it had been 

 boiled, although it still continued capable of supporting the life and 

 encouraging the rapid multiplication of any of these organisms which were 

 purposely added to it. Some of this boiled solution, therefore, was 

 introduced into flasks previously washed with boiling water ; and when 

 the fluids had sufficiently cooled, that of each flask was inoculated with 

 living Bacteria and Vibriones — in the proportion of one drop of a fluid 

 quite turbid with these organisms to one fluid ounce of the clear saline 

 solutionf. These mixtures containing an abundance of living organisms 

 were then heated to various temperatures, ranging from 122° P. (50° C.) to 

 167° P. (75° C.) ; and it was invariably found that those which had been 



* Seasons for this opinion have been fully set forth in ' The Beginnings of Life,' 

 vol. i. pp. 374 et scq. ; or the discriminating reader may at once find my justification 

 for this expression by reading pp. 58-60 of M. Pasteur's memoir in ' Ann. de Chim. et 

 de Physique,' 1862. 



t Fuller details concerning these experiments may be found in the little work 

 already mentioned at pp. 51-56, and also in ! The Beginnings of Life,' vol. i. pp. 

 325-332. 



