30 
4 
growth in rich soil. Were this the csist Ifumn/us v/ou\d mean 'little 
moist earth,' a nonsensical name to apply to a plant. 
Du Cange, in his Glossarium mediae et infimae Latinitatis gives the 
forms Jiunilo^ humulo^ htimelo^ humolo, humuhis^ and, under one of them, 
says, *'ex Gall. Jioiiblon^ quod a Latino lupulum formatum, elisa litera 
/."! This, although pretty bad etymologizing, was good enough for 
the period at which it was put forth, and is of value as showing that 
Du Cange considered these low Latin words as borrowed from a 
living language, as is indeed the case. They are probably, as 
Skeat (Etymol. Diet.) states, of Teutonic origin (O, Du. hommell, 0. 
Norse huniall, Swed., Dan. and Norweg- humle), although similar 
names for the hop are to be found in the Slavonic dialects, and in 
Finnic and Tartaric. Other Teutonic names for the hop are: 0. H. 
Ger. hopfo, M. H. Ger? hopfe, hoppe, Ger. hopfen, Flem. hoppe 
(whence O. Eng. hoppe, Eng. hop), Du. hop, Skeat would connect 
these two forms, and derive the latter from the Aryan root kap, 'to 
undulate,' 'bend,' in allusion to the twining nature of the plant, and 
the former from this same root nasalized — kamp. 
W. R. G. 
Botanical Notes. 
The Coloration of Autumn Leaves.— Mr, H. C. Sorby, who has for 
several years been studying the subject of the coloration of autumn 
leaves, gives (in Nature) the following conclusions in regard to it. 
As a general rule the color of leaves in their normal condition de- 
pends on a variable mixture of two perfectly distinct green pigments 
and of at least four perfectly distinct yellow substances. The deveb 
oi)ment of the autumnal tints is mainly due to the disappearance or 
change of the green constituents and to the production of highly- 
colored pigments by the oxidization of previously existing very pale 
or colorless substances. It is, in fact, due to a more or less complete 
loss of the vitality which previously counteracted these chemical 
changes, and the order in which the tinis are developed can be easily 
explained, if we assume that the death of the leaves takes place some- 
what gradually. The first visible effect of the reduced vitality is the 
change in the green pigments. In many cases they appear to be 
converted into colorless products, since the resulting bright yeiloNV 
leaves dififer from the normal green in the absence of chlorophyll, and 
merely contain the usual previously existing yellow pigments. At 
the same time it is quite possible that an increased quantity of some 
of these yellow substances may be formed as a product during the 
change, but of this there is no positive proof. In the case of such 
trees as the alder, the chlorophyll does not thus dirappear, but is 
changed by the presence of a weak acid into a very stable brownish- 
green product which resists further change. The production ot 
bright yellows or dull browns thus clearly depends on whether the 
chlorophyll does or does not disai)pear before being modified by the 
action of acids, as may be verified experimentally by exposing suitabl 
*It is well to note here, however, that Nemnich (Allgemeines Polygl^^tten 
Lexicon der Natur-geschichte) gives hymel ^% the Persian name of the plant. 
