A 
MEMBERS OF THE MICROSCOPIC SECTION. 307 
Foraminifera, I was strongly influenced by Ehrenberg’s 
opinion that they were Bryozoa, and gave countenance to 
that opinion in a Paper on the “ Levant Mud,” published in 
the Transactions of the Manchester Literary and Philoso- 
phical Society. Thus I was, for some time at least, the 
means of diffusing an erroneous idea. On the other hand, 
a youthful, overweening confidence, and a deficiency in 
modesty and merited respect for truly great men, cannot 
be too strongly reprehended. Try to hit the golden mean. 
One of the most important studies that can claim your 
attention is that of the mysterious principle of life. Far 
be it from me unduly to check the aspirations of any phi- 
losophic student; but it may save us from uselessly ex- 
pending our strength, to remember that there are some 
subjects which must be studied under limitations; sub- 
jects which, whilst the phenomena they present demand 
the devotion of our best energies, we may never hope, at 
least in this world, fully to comprehend their cause. Life 
is one of these subjects. We cannot apprehend it; we can 
only study its functions. Its source lies beyond the field 
of our mortal experience, and, probably, we shall never 
know more of its primary nature than we do at present. 
But the microscopist has already done much to remove 
misapprehension respecting it, and will do more. When 
Leeuwenhoek commenced his researches on this subject, 
he found it loaded with absurdities, most of those who 
preceded him, from Aristotle to Philippo Bonani, believed 
in spontaneous generation; even in his day this idea was 
not only applied to the obscure lower animals, but to those 
of comparatively higher organization, such as shell-fish 
and corn-weevils ; and Leeuwenhoek found himself under 
the necessity of refuting such absurdities, by demonstra- 
ting that these objects were produced, like other animals, 
by the ordinary modes of generation. Driven from these 
positions, men were still unwilling to abandon the idea, 
VOL. XV. Ss 
