430 TRANSACTIONS OF THE CANADIAN INSTITUTE. (Vou. VIII. 
ever appeared in them so long as they were contained in such air- 
excluding vessels. 
The discovery of oxygen and its properties led those who accepted 
spontaneous generation to claim that in ‘these experiments of Spallan- 
zani and others, one of the most necessary factors, namely oxygen, was 
excluded, and thus their results did not confute the idea of spontaneous 
generation. The discussion on the subject went on on this basis 
through the early years of the last century but it was closed only on 
the publication of the results of Schroeder and Dusch in 1854 and of 
Schroeder in 1859. These observers found that when, ‘instead of her- 
metically sealing by fusion the necks of the vessels containing infusions 
of animal or vegetable matter, the mouths were closed with plugs of 
cotton wool, the infusions, which were heated as in Spallanzani’s experi- 
ment, did not subsequently contain animalcule, although the oxygen, 
but not the organisms, of the atmosphere gained ready entrance to the 
medium through the cotton wool. 
The net result of the investigations of the last half-century has 
been to show that living matter does not originate spontaneously under 
any condition which obtains on the globe to-day, nor can it be granted 
that it may arise spontaneously in any culture medium however favor- 
able the latter may be to the generation of living forms de xovo. It is 
necessary to be thus explicit for otherwise I might be understood as 
accepting views which are still advanced in certain quarters, but which 
seem to me to be utterly untenable. 
To repudiate spontaneous generation and to believe that a living 
form did at one time in the history of the globe arise from non-living 
matter are two very distinct positions to take and yet I accept them 
both as tenable. It is not necessary to defend the first for I have already 
said enough to that end. The second position is practically that already 
taken by biologists generally. Huxley, whose address as President of 
the British Association for 1870 was a crushing refutation of the doc- 
trine of spontaneous generation, practically endorsed that position in 
language which will bear repetition here. After indicating his inability 
to hold any belief as to the primal origin of life he went on to say :— 
“ But expectation is permissible where belief is not, and if it were given 
me to look beyond the abyss of geologically recorded time to the still 
more remote period when the earth was passing through physical and 
chemical conditions, which it can no more see again than a man can 
recall his infancy, I should expect to see it appear under forms of great 
