216 THE LIFE OF PASTEUR 



itself, which, put in contact with air, gives birth to grains of 

 yeast by the transformation of albuminous matter, whilst 

 M. Pasteur declares that the grains of yeast are produced by 

 germs." According to M. Fremy, ferments did not come from 

 atmospheric dusts, but were created by organic bodies. And, 

 inventing for his own use the new word hemiorganism, M. 

 Fre"my explained the word and the action by saying that there 

 are some hemiorganized bodies which, by reason of the vital 

 force with which they are endowed, go through successive 

 decompositions and give birth to new derivatives ; thus are 

 ferments engendered. 



Another colleague, M. Tre'cul, a botanist and a genuine 

 truth-seeking savant, arose in his turn. He said he had wit- 

 nessed a whole transformation of microscopic species each into 

 the other, and in support of this theory he invoked the names 

 of the three inseparables Pouchet, Musset and Joly. Him- 

 self a heterogenist, he had in 1867 given a definition to which 

 he willingly alluded : ' ' Heterogenesis is a natural operation 

 by which life, on the point of abandoning an organized body, 

 concentrates its action on some particles of that body and 

 forms thereof beings quite different from that of the sub- 

 stance which has been borrowed." 



Old arguments and renewed negations were brought forward , 

 and Pasteur knew well that this was but a reappearance of the 

 old quarrel ; he therefore answered by going straight to the 

 point. At the Academie des Sciences, on December 26, 1871, 

 he addressed M. Trecul in these words: "I can assure our 

 learned colleague that he might have found in the treatises I 

 have published decisive answers to most of the questions he has 

 raised. I am really surprised to see him tackle the question 

 of so-called spontaneous generation, without having more at 

 his disposal than doubtful facts and incomplete observations. 

 My astonishment was not less than at our last sitting, when 

 M. Fre"my entered upon the same debate with nothing to pro- 

 duce but superannuated opinions and not one new positive 

 fact." 



In his passion for truth and his desire to be convincing 

 Pasteur threw out this challenge : "Would M. Fremy confess 

 fois error if I were to demonstrate to him that the natural juice 

 of the grape, exposed to the contact of air, deprived of its 

 germs, can neither ferment nor give birth to organized 

 yeasts?" This interpellation was perhaps more violent than 



