OCCURRENCE OF ARCHEBIOSIS 147 



The requirements, underlying all attempts to prove the " spon- 

 taneous generation" of living matter by flask experiments with 

 superheated fluids, are of two kinds. We have (a) to ascertain as 

 far as possible, by preUminary trials, the lowest amount of heat, 

 and the duration of its application, which is necessary for the 

 destruction of pre-existing Uving things within the experimental 

 vessels. And we have (6) to see whether it is possible that fluids 

 submitted to the lowest necessary amount of heat to ensure the 

 destruction of all pre-existing life can still, by subsequent treatment 

 under what are at the best only very unfavourable conditions, be' 

 induced to engender living matter. 



Everything of course turns upon these words " lowest necessary 

 amount of heat." 



The destructive and deteriorating influence of heat upon the 

 organic fluids with which experiments have to be made must be 

 obvious to all ; and the ultimate deteriorating results may not be 

 very different where recourse is had to one process of heating at 

 a high temperature, or to several successive heatings at rather 

 lower tempei-atures as in the "discontinuous process" adopted by 

 Tyndall. No one need doubt the truth of the naive remark of 

 Fischer ' when he says, " Infusions of organic substances, if they 

 be only boiled long enough, will remain sterile for years." 



The essential question is, therefore, what is the lowest necessary 

 amount of heat to ensure, on the one hand, that all pre-existing 

 living things shall be killed and to avoid as far as possible extreme 

 deterioration by heat of the fluids employed. It has now been 

 thoroughly brought home to us how impossible it is to arrive at a 

 trustworthy and generally acceptable conclusion in regard to this 

 question. In death-point experiments (a) the barrenness of the 

 fluid may merely mean that the organisms are inert rather than 

 dead. I freely admit this as a possibility, and moreover, judging 

 from the past history of this question, feel certain even if there 

 were a new basis of agreement in regard to the death-point of 

 micro-organisms in any particular fluid, that this common point 

 of agreement would be immediately renounced, by many, directly 

 some experimenter claimed that from such a basis he had demon- 

 strated the ' spontaneous generation ' of living matter. He would 

 doubtless be told that 'spontaneous generation' was a chimera, 

 and that he had only succeeded in resuscitating germs which all 



' " The Structm-e and Functions of Bacteria," Trans., rgoo, p. 51. 



