is
experimentally proved and that which is still in the region of
speculation. As to the latter, Virchow by no means imposes silence.
He is far too sagacious a man to commit himself, at the present time
of day, to any such absurdity. But he insists that it ought not to be
put on the same evidential level as the former. 'It ought,' as he
poetically expresses it, I to be written in small letters under the
text.' The audience ought to be warned that the speculative matter is
only _possible_, not _actual_ truth--that it belongs to the region of
'belief,' and not to that of demonstration. As long as a problem
continues in this speculative stage it would be mischievous, he
considers, to teach it in our schools. 'We ought not,' he urges, 'to
represent our conjecture as a certainty, nor our hypothesis as a
doctrine: this is inadmissible.' With regard to the connection between
physical processes and mental phenomena he says: 'I will, indeed,
willingly grant that we can find certain gradations, certain definite
points at which we trace a passage from mental processes to processes
purely physical, or of a physical character. Throughout this
discourse I am not asserting that it will never be possible to bring
psychical processes into an immediate connection with those that are
physical. All I say is that we have _at present_ no right to set up
this _possible_ connection as _a doctrine_ of science.' In the next
paragraph be reiterates his position with reference to the
introduction of such topics into school teaching. 'We must draw,' he
says, 'a strict distinction between what we wish to _teach_, and what we
wish to _search for_. The objects of our research are expressed as
problems (or hypotheses). _We need not keep them to ourselves; we are
ready to communicate them to all the world_, and say "There is the
problem; that is what we strive for." ... The investigation of such
problems, in which the whole nation may be interested, cannot be
restricted to any one. This is Freedom of Enquiry. But the problem
(or hypothesis) is not, without further debate, to be made _a
doctrine_.' He will not concede to Dr. Haeckel 'that it is a question
for the schoolmasters to decide, whether the Darwinian theory of man's
descent should be at once laid down as the basis of instruction, and
the protoplastic soul be assumed as the foundation of all ideas
concerning spiritual being.' The Professor concludes his lecture thus:
'With perfect t