214 THE EVOLUTION OF LIFE 
fermentation in boiled and guarded fluids, had three 
years previously been brought about by me in the 
presence of a highly skilled and then sceptical 
witness, Professor Burdon Sanderson. He _  sub- 
sequently published his declaration! that positive 
results, both with acid and with neutral boiled in- 
fusions, had been obtained without experimental 
flaw; yet in spite of this testimony, and without 
even mentioning it, Professor Tyndall sought to 
decry my experiments and set aside my results. 
Meanwhile, almost at the time that the learned 
physicist was acting in this bewildering manner, one 
of the principal authorities on such subjects in 
Europe, Professor Ferdinand Cohn, was again con- 
firming my impugned experiments at Breslau; and 
was obtaining, both with acid and with neutral boiled 
infusions, those evidences of fermentation which 
hitherto Professor Tyndall had strangely enough 
failed to reproduce.? The fact was again fully 
admitted by Professor Cohn, though my interpreta- 
tion of it was still questioned. It is therefore quite 
needless for me here even to cite the other in- 
vestigators who had previously obtained similar 
results. This side of the question has, in fact, 
been so thoroughly settled by my experiments, 
and the numerous confirmations which they had 
received at the hands of others, that it would be 
1 Nature, January 8, 1873, and reproduced in Chapter xii. 
2 “Beitrage zur Biologie der Pflanzen,” 1876, p. 259. This con- 
firmation, after Professor Tyndall’s denial, was very similar in its 
opportuneness to that of Professor Sanderson after Prof. Ray 
Lankester’s earlier but similar denial and failure (Quart. Journ. of 
Microsc. Science, January 1873, vol. xiil. p. 74). 
