li 



tion, and indeed demanding a fall and final explanation before 

 satisfactory progress could be made in this direction. 



The researches to which we find Pasteur next devoting himself 

 were directed to the settlement of the much vexed question — Can 

 life originate spontaneously ? It is impossible here to describe the 

 history of this momentous controversy, but so unsatisfactory was the 

 state of scientific opinion on this question in 1860 that the Academy 

 of Sciences gave as a subject for a prize competition : " Essayer, par 

 des experiences bien faites, de jeter un jour nouveau sur la question 

 des generations spontanees." It is at this moment that Pasteur 

 enters the lists, and the circumstance that we have for more than 

 twenty years heard nothing of the doctrine of spontaneous genera- 

 tion is due to the effectual manner in which he successively hurled 

 into the dust the several champions who appeared on its behalf in the 

 intellectual tournament which followed. 



In looking back upon this period of Pasteur's career, one is dis- 

 posed to regret that his great f powers should have been so long absorbed 

 in this work of exterminating a mere superstition, but, as a matter of 

 fact, much good came of this crusade iu a number of ways. Inci- 

 dentally, experiments, which have now become classical, were made 

 on the distribution of micro-organisms in our surroundings such as 

 air and water, whilst healthy urine and the blood of normal animals 

 were, in 1862 and 1863, shown to be free from microbes and capable 

 of being preserved without alteration for an indefinite period of 

 time, provided they were collected with suitable precautions. Van 

 der Broeck had, indeed, already, in 1857 and 1858, proved that 

 grape-juice, white and yolk of egg, gall, urine, and arterial blood, if 

 suitably collected, could be preserved without change in their 

 natural condition, whilst subsequently sterile milk in its natural 

 condition was obtained direct from the udder by Lister, Cheyney 

 Meissner, and others. The spontaneous generation controversy was, 

 moreover, highly fertile in developing the general methods of bacte- 

 riological research, and many of the most familiar operations em- 

 ployed in the study of micro-organisms date from this period. 



It is almost needless to say that the prize offered for researches 

 throwing light on the question of spontaneous generation was 

 awarded to Pasteur, and in 1862, at the age of forty, he was elected 

 a member of the Academy of Sciences. 



Pasteur now returned to his fermentation studies, and about this 

 time we find him delivering an address to the vinegar manufacturers 

 of Orleans, an address which has since become famous by reason of 

 the important revelations which it contained concerning the pro- 

 duction of vinegar by new methods. He had shown that the con- 

 version of wine into vinegar is the work of a minute rod-like 

 organism, which he called Mycoderma aceti, and he was now able to 



