(2 
microbia found in decaying matter are derived from similar ancestors. No 
man would now be justified in practical life in acting on the possibility of a 
generate equivoca of nicrobia. A physician who finds himself in pre nee 
of infectious disease among his patients, or an agriculturist whose crop. are 
blighted, or a man engaged in the production of alcohol or sugar by fer- 
mentation, must set himself to discover what brings about the changes that 
he has to deal with; he must see that organisms are there which have 
been imported from without, and must then inquire whence they had been 
derived, The physician who has to combat an epidemic, dare not act if the 
germ were spontaneously produced in any patient. Such is the difference 
between logical possibilities and the practical work of daily life. Every 
teacher of science must lead his students to suppose that each living being 
that he meets must have had a father and a mother, or at least one or 
other of them ; and every scientific conclusion maintains that one generation 
is legitimately descended from another precisely similar. That was one con- 
sideration that led ine to warn my fellow-countrymen against developing a 
system out of logical possibilities. At the very time when we were getting 
free from the chains of former dogma, we seemed to be in danger of forging 
new ones for ourselves. 
“The second question concerning Darwinism had regard to the descent of 
man, whether from apes or some other vertebrate animal. Was there any- 
where a pro-anthropos? Inregard to this question, I thought that the existence 
of such a precursor of man was a logical possibility, perhaps a probability. 
Only I found, to begin with, that it wasa purely speculative question ; not 
one raised by any observed phenomenon. No pro-anthropos had ever been 
discovered ; not even a fragment of him. I had myself long been specially 
occupied in making pre-historic investigations to get near the primitive 
man. When I began these studies, twenty years ago, there was a general 
disposition to arrive at this discovery. Everybody who found a skull in 
a cave or a bone in the fissure of a rock, thought he had got a bit 
of him. I wish you specially to notice that the smaller the fragment of 
skull, the easier it was to make it out to be the skull of the pro-anthropos. 
It was never thought of where the entire skull was in hand. When the 
upper part of the cranium alone—the calvarium without the face and the 
base, as in the case of the Neanderthal skull,—was discovered, it was easy, 
by changing its horizontal position, by elevating either the anterior or 
posterior part, to give the impression that it had belonged either to a being 
of a superior or inferior race. You can make the experiment with any calva- 
rium. If you make a series of diagrams of skulls, placing them over each 
other, you may make them appear similar or dissimilar, according as you 
choose one or another fixed point for bringing them into relation. I should 
like to impress upon you that every discovery of that kind should be 
received with caution and scrutiny. In my judgment no skull hitherto 
discovered can be regarded as that of a predecessor of man. In the course 
of the last fifteen years we have had opportunity to examine skulls of 
all the various races of mankind,—even of the most savage tribes—and 
among them all no group has been observed differing in its essential 
characters from the general human type. So that I must say that an 
anthropological teacher has not occasion to speak of a pro-anthropos except 
as a matter of speculation. But speculation in general is unprofitable. As 
Goethe says,—‘ A speculating fellow is like a beast on a barren heath led 
about by the Evil Spirit. The day before I gave the address in Munich 
to which I have referred, Haeckel had gone so far as to propose to introduce 
into our schools a new system of religious instruction based upon the doctrine 
of the ‘Descent of Man’; and [I still think it necessary to guard against 
the danger of constructing systems of doctrine out of possibilities, and 
making these the basis of general education.” 
