382 THE ZOOLOGIST. 
protection, attraction, or aggression, there are still immense ex- 
ceptions to the rule. This is particularly evident to anyone who 
has witnessed the glorious autumnal tints exhibited by the foliage 
of trees along the mountain slopes of the Rhine and Danube, and 
on the shores of the Canadian lakes.* 'l'hese beautiful shades 
of red, violet, and yellow merely denote the proximate fall of the 
leaf and chemical processes incidental thereto. Many leaves— 
due to anthocyanin—are highly coloured on their under surfaces, 
a process probably which absorbs light and changes it into heat, 
and thus “in the ever green leaves of those plants in the depths 
of the forest which are natives of inclement regions, this advan- 
tage is obtained from the layer of anthocyanin developed on the 
lower leaf-surface, that every sunbeam, even in the cooler seasons, 
can be utilized to the utmost.” f 
We may probably have reached a stage in our 1 ingerieatiogs 
where suggestion may at least be valuable during a halt, and, 
where consideration may be given to facts, and attention to 
questions, which do not altogether quite advance new theories 
nor disprove older ones. Let us bring grist to the mill, even if 
others alone are capable of producing the meal; surely the 
naturalist can collate his facts, give his experience, and propound 
his views, without seeking a ‘‘ patent” for every idea, or to be 
the parent of another theory. At the present time, among many 
students of biology there seems a desire to advocate what may be 
called a personal theory. Such workers will, with the greatest 
avidity, dissect and criticise the theories advanced by others. 
But their own theory is sacred, is, in fact, ‘‘totem.” This feeling 
is almost a form of survival. According to Turner, one Samoan 
saw his god in the Hel, another in the Shark, another in the 
* Brehm has described similar autumn beauties in the woodlands of 
Western Siberia. (‘From North Pole to Equator,’ p. 130.) 
+ Kerner and Oliver, ‘Nat. Hist. Plants,’ vol. i. p. 521. A case which 
seems to imply non-utility in vegetable markings is given by Prof. Thiselton- 
Dyer :—‘‘ There is a variety of the common oak with marbled foliage. A 
tree at Tortworth has borne acorns, and these are striped. At first sight it 
might seem odd that a variation in foliage and fruit should be correlated. 
But it is not so; the marbling is due to the partial suppression of chlorophyll 
in those portions of the ground-tissue which are exposed to light; and this 
tract of tissue igs continuous in the leaves and the carpels” (‘ Nature,’ 
vol. liv. p. 293). 
