OCCURRENCE OF ARCHEBIOSIS 151 



appearance of organisms therein is to be ascribed to survival of 

 germs, or to germinality of the fluids. 



The tendency with Pasteur, and with Tyndall and others has 

 been too much altogether to ignore this latter possibility, to regard 

 it as a chimera, and one not to be seriously considered. But 

 this, as was well said by Rucker in his Presidential Address 

 before the British Association in 1901, concerning the one-sided 

 attitude of some in reference to a fundamental physical problem, is 

 "to heg the -whole question at issue; to decide the cause before it has 

 been heard." 



It is worthy of note, moreover, that my opponents in this 

 question have invariably assumed, rather than proved, various 

 points needful to give adequate warranty to their interpretation 

 of the appearance of living organisms in critical flask experiments. 



They know quite well that spores are distinctly more resistant 

 to heat than the parent organisms ; they know that the parent 

 organisms without spores are almost infinitely more common than 

 such organisms with spores ; they know that even under most 

 favourable conditions such spores will often refuse to develop ; yet 

 whenever living organisms appear in the guarded fluids which 

 have been heated far more than is necessary for the destruction 

 of the parent organisms, they invariably assume that the much 

 rarer spores have been present, and they further find it necessary 

 to assume that the spores which are often most slow to develop 

 under favourable conditions, now, in spite of the injurious heating 

 and unfavourable conditions in which they are placed, straightway 

 hasten to develop, grow and multiply. This, is surely, more like 

 begging the question at issue, than judging in accordance with 

 evidence. 



In addition to the above considerations, it may not be without 

 interest to some that attention should be called to the following 

 additional facts, seeing that they may help to show in which 

 direction the balance of evidence at present lies. 



(a) Thermal death-points and their relation to certain old flask 

 experiments. 



The dicta at present given in regard to thermal death-points are 

 these. Pasteur formerly said that a brief exposure to 110° C. was 

 sufficient to sterilise all fluids ; but now his former assistant, 

 Chamberland, as a result of investigations made between 1877 



