THE BEGINNINGS OF LIFE. 381 



course, would not fail to see that he was bound to give 

 equal attention to each of these possibilities. He would 

 have no right to assume that the probabilities were 

 greater in favour of the one mode of explanation than 

 they were in favour of the other; this was the very 

 subject in dispute this it was which had to be proved. 

 When, therefore, it was definitely ascertained by M. 

 Pasteur that acid solutions employed in Schwann's ex- 

 periments yielded negative results as far as organisms 

 were concerned, the establishment of this fact was in 

 reality no more favourable to the one view than to the 

 other. It is what the panspermatists might have ex- 

 pected, it is true, because regarding it only as a 

 question of the destruction or non-destruction of germs 

 even they had convinced themselves that calcining 

 the air and boiling the fluids were adequate to destroy 

 all living things contained in these media. But on the 

 other hand, it was equally open to the evolutionists to 

 say, that the restrictive conditions employed were so 

 severe that they also were not surprised at the fermen- 

 tative changes being stopped and at the consequent 

 non-appearance of organisms in the solutions. When 

 positive results were obtained, however, the case be- 

 came altogether different. The rule with regard to the 

 inability of living things to survive in solutions which 

 had been raised to the boiling temperature for a few 

 minutes was absolute, so far as it had gone, and being 

 founded on good evidence, to which M. Pasteur and 

 others had assented, no one should have attempted to 



