78 



DE. BASTIAN ON THE 



ment of confusion into tlie subject wMcli was wholly needless and 

 easily to have been avoided ? 



The effects of dry heat (which is well known to be less dama- 

 ging to life) are set forth when it would have been quite as easy 

 and much more satisfactory to have given instead, or, in addition, 

 the effects of heat upon these organisms and their germs when 

 they were in the moist state *. The consequence has been that 

 these results with dry heat have been quoted by subsequent 

 writers as though they fell into the same category as others 

 which have been made with moist heat ; and differences of result 

 which, in the main, have been due to different modes of expo- 

 sure, have been ascribed to different powers of resistance on 

 the part of simple organisms and their germs. Professor Tyndall, 

 indeed, has gone so far as to speak of the "grave error" which 

 biologists have hitherto made in failing to recognize this impor- 

 tant distinction concerning germs and organisms respectively; 

 yet, as a matter of fact, the possibility of such a difference has 

 been clearly before the minds of all the principal workers on these 

 subjects from the time of Spallanzani downwards f. 



But the fallacy of all this may be seen from the fact that in 1862 

 M. Pasteur J himself found that certain of the germs or spores of 

 fungi, especially those of the common mould Penicillium, would 

 germinate after exposure to a dry heat of 121° C. (250° F.) for thirty 

 minutes, though, as he says in an earlier part of his memoir 

 (p. 60), he had proved by direct experiment tliat when im- 

 mersed in fluid, even for a few minutes, at a temperature of 

 100° C, all such germs were killed. Seeing that, according to 

 the experience of Dallinger and Drysdale, their spores and spo- 

 rules, in the dry state, were no better able to resist the momentary 

 influence of 121° C. than of 148° C, and that Pasteur found 

 spores which could resist a dry heat of 121° C. even for tJiirtT/ 

 minutes were yet invariably killed when immersed in boiling water 

 for two or three minutes, there is no reasonable ground whatever 



* It would have been perfectly easy to have put one or two drops of the fluid 

 into a small tube, to have hermetically sealed it, and then to have heated it for 

 10 minutes or more to different degrees before subjecting the fluid to a prolonged 

 microscopical examination upon a carefully prepared slide. 



t In my ' Ev^olution and the Origin of Life,' 1874, pp. 141-168, Spallanzani's 

 views on the subject are set forth and duly considered, as well as all other 

 evidence that was at the time available. 



\ Ann. de Cbira. et de Phys. t. Ixiv. pp. 92-99. 



