HELIOTROPISM OF ANIMALS §1 
desire to eramine the new and striking object;” and then 
quotes some remarks which he found in the manuscripts of 
Darwin: “Query: Why do moths and certain gnats fly into 
candles, but not into the moon when the same is at the hori- 
zon? I noticed long ago that they fly much less frequently 
into candles on a moonlight night. When a cloud passes 
over the moon, they are again attracted by the candle.” 
Romanes believes that: “The answer must be that the moon 
is a familiar object, which insects consider as a matter of 
course, and so have no desire to examine it.” 
As we have seen, it is not the “new and striking’’ object 
and “the desire to examine it” which drive the insects to 
the lamp, for they are attracted, as I have shown, also by 
the natural source of light, the sun. No reason seems to 
exist to my mind for believing that the moon is a more 
familiar object to the insects than the sun. I cannot well 
see, however, how Romanes harmonizes the phenomena of 
negative heliotropism in animals with “the desire to examine 
unfamiliar objects.” The history of science has taught us 
that confusion always reigns when anthropomorphic motives 
are brought into scientific research. Before the time of 
Galileo a body sinking in a fluid “sought its place.”’ Galileo 
and his followers put an end to the sovereignty of this 
psychology, at least in inanimate nature. Mankind has had 
no reason to regret this revolution. In biology, however, 
even at this date, protoplasmic substances still move toward 
the source of light “because of curiosity.” 
‘XIII. SUMMARY OF RESULTS 
I shall conclude by summarizing the more important 
results of my investigation: 
I. The dependence of animal movements on light is in 
every point the same as the dependence of plant movements 
on the same source of stimulation. 
1See Maca, Geschichte der Mechanik, 1st ed., p. 117. 
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