440 



THE POPULAR SCIENCE MONTHLY.— SUPPLEMENT. 



by Prof. Tyndall as an interpretation of the ap- 

 pearance of such specks which " violates all an- 

 tecedent knowledge." This cannot be true; it 

 may be at variance with a favorite argument from 

 analogy, but, as regards the cause of the phenom- 

 enon itself, this is, and ever has been, beyond the 

 reach of "antecedent knowledge." As I have 

 elsewhere ' pointed out, living matter, like crystal- 

 line matter, can originate or come into being only 

 by a synthesis of its elements ; but because organ- 

 isms (owing to the intrinsic properties of living 

 matter) have well-known powers of self-multipli- 

 cation, the obviousness of these modes of repro- 

 duction has sufficed to cast doubts upon the 

 reality of the independent origin of the lowest 

 living units, by supplying material for the build- 

 ing up of a plausible but one-sided analogical 

 argument against the reality of that which must 

 always remain beyond the sphere of actual ob- 

 servation. 



After the before-mentioned confirmation of 

 my experiment by others in 1873, and after wit- 

 nessing the ease with which the old beliefs as to 

 the destructive influence of fluids at 212° Fahr. 

 upon ferment organisms and their germs were 

 then thrown aside," I immediately instituted new 

 inquiries concerning the death-point of such or- 

 ganisms in fluids, in order to try and ascertain 

 again whether there was or was not any justifi- 

 cation for this procedure. 



This new series of experiments, of which a 

 record is to be found in the " Proceedings of the 

 Royal Society" for 18Y3, seems to show conclu- 

 sively that the bacteria and all the reproductive 

 particles which they may possess, which were 

 purposely immersed in the organic infusions with 

 which the experiments were made, were killed, as 

 I had previously ascertained, at a temperature of 

 140° Fahr. Similar experiments were made very 

 shortly afterward, in the same manner, by Prof. 

 Cohn, of Breslau, assisted by Dr. Horvath, and 

 they also arrived at the conclusion that the com- 

 mon bacteria were killed in fluids by a brief 

 exposure of from five to ten minutes to a temper- 

 ature of 140° Fahr. Although these experiments 

 were made after mine, they seem to have been 

 executed without any knowledge of my results, 

 so that the independent confirmation which they 

 afford is all the more satisfactory. 



The method of procedure employed in these 

 experiments was of such a nature that the con- 

 clusion arrived at was, as I pointed out at the 

 time, applicable to any germs, whether visible or 



1 "The Beginnings of Life,"' vol. ii., p. 77 



invisible, by which bacteria may multiply in fluids, 

 as much as to the parent organisms themselves. 



When Prof. Tyndall was at last, after his un- 

 successful " Combat with an Infective Atmos- 

 phere," ' compelled to turn his attention from 

 this side of the subject to the heat-resisting 

 powers of living matter, in order to find some 

 hypothesis which would explain the very contra- 

 dictory results of his first and of his second series 

 of experiments, the public generally was told 

 through the Times of the 9th of June last, as 

 his audience at the Royal Institution had been 

 on the previous evening, that " the gravest error 

 ever committed by biological writers on this ques- 

 tion consists in the confounding of the germ and 

 its offspring." Though the parent organisms 

 were, as he was prepared to admit, killed at 140° 

 Fahr., it was far otherwise with the " germs," 

 which, though invisible, were described as " in- 

 durated and resistent." 



Now, it is difficult to conceive any statement 

 more hopelessly incorrect than this of Prof. Tyn- 

 dall with respect to the supposed '"error" of 

 biological writers. As above indicated, any dis- 

 tinction existing between germs and finished or- 

 ganisms in regard to their resistance to heat had 

 always been thoroughly borne in mind by me, 

 and the same may be said of all the principal 

 workers from the Abbe Spallanzani downward. 

 Moreover, in my " Evolution and the Origin of 

 Life" I devoted many pages (pp. 141-168) to a 

 discussion of all the most important facts which 

 were then known in regard to this question. 



But again our attention has been called to an- 

 other thoroughly familiar fact, as though it were 

 one which had hitherto escaped attention. In 

 order seemingly to explain Prof. Tyndall's sup- 

 position that the invisible germs whose existence 

 he postulates are really " indurated and resistent," 

 as he imagines, we have been more than once re- 

 minded that the (wholly different) desiccated seeds 

 of many plants which are provided with thick 

 and horny coats can resist the penetration of 

 water for a very long time, and can even retain 

 their vitality occasionally after they have been 

 boiled in water for four hours. 



But Prof. Tyndall tries to make even a more 

 specific use of this fact. In this Review last 

 month, after referring to some statements which 

 I have made in reference to the influence of boil- 

 ing water upon living matter, he adds : 



"But to invalidate the foregoing statements it 

 is only necessary to say that eight years before 

 they were made it has been known to the wool- 



1 British Medical Journal, January 27, 1877. 





