S'JUDIES ON FliRMENTATlON. 97 



ferment might easily have multiplied to such an extent as to 

 make the discovery of the spores that had been sown a matter 

 of some difficulty, since those spores would have been lost 

 amongst the great number of cells of ferment. This was, pro- 

 bably, one of the causes which led to the mistaken notion that 

 such spores underwent conversion into cells of ferment. Now 

 although botanists describe several varieties of i^eniciUiam 

 glaucum, we do not suppose that the cause of the difference 

 between our results and those obtained by M. Trecul can be 

 attributed to our having operated upon a different variety of 

 penkilUuin from that which he used. Supposing that there 

 had been a great difference between our two varieties, still 

 M. Trecul declares that he has realized the phenomenon with 

 numerous varieties of this fungus. 



M. Trecul expresses himself as follows : "I have used spores 

 oi peniciUium of several varieties in these experiments : Firstly, 

 thick, green, elliptic spores of a variety of penicilUum that grows 

 on lemons ; secondly, elliptic spores of a bluish colour and 

 smaller than the preceding, of another variety oipenicillium found 

 on lemons ; thirdly, spherical spores of the variety ievrnQdi penicil- 

 Uum crustaceum ; fourthly, spores of the 2ienicillium that develops 

 on the yeast of beer.* 



This criticism of M. Trecul's opinions was written on the 

 occasion of a discussion at the Academy, after we had been 

 induced to read over again the remarks which he had published 

 on the subject. We were so impressed by the positive manner 

 in which his conclusions were stated, that we asked ourselves, 

 once more, which of us could be mistaken, and once more, also, 

 we applied ourselves to fresh experiments, which we conducted 

 with every possible precaution, following, as far as we could 

 without falling into the errors of which we accuse the learned 

 botanist, the mode of procedure that he adopted. As his descrip- 

 tions struck us as being at times insufficient, we resolved to ask 

 him for certain explanations vim voce (November 3rd, 1873), 

 which he gave us with the greatest willingness. 



* Comptes rendus des Seances de VAcadeinie des Sciences, t. Ixxv • 

 p. 1220; Nov. 18, 1872. 



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