424 
EXTRACTS—NATURAL HISTORY. 
which it afterwards emitted. On the'strength of this proof of the power of plants 
to give out what they before had taken up, a new theory has been founded, im¬ 
porting that in this respect they resemble animals, taking in food by one set of 
organs, and after appropriating to themselves by assimilation such parts of it as 
may be suitable for their sustenance, disgorge the refuse by the same or some 
other organs, into the earth. The necessity of a rotation of crops, is accounted 
for on this hypothesis—the plants discharging their foeces into the earth con¬ 
taminate and render it unfit for the support of plants of the same kind following 
on the same spot. 
Appearances and Influences of the Moon. —It is generally believed, 
especially in the neighbourhood of Paris, that the moon in certain months has a 
great influence on the phenomena of vegetation. They give the name.of “red 
moon” (lune rousse) to the moon, which, beginning in April, becomes full either 
about the end of that month or in the course of May. It is maintained that 
during these two months, when the sky is clear, the leaves and buds exposed to 
this light become red, that is to say, frozen, although the thermometer in the 
free atmosphere, should stand several degrees above the freezing point; and that 
if the rays of the moon be intercepted by clouds, and prevented from reaching 
the plants, the same effects do not take place, under circumstances perfectly 
similar in other respects with regard to temperature. No one had supposed, 
befox’e Dr. Wells, that terrestrial substances, excepting in the case of very rapid 
evaporation, may acquire, during the night, a different temperature from that of 
the surrounding air. This important fact is now well ascertained. We cannot, 
therefore, judge of the degree of cold with which a plant is affected during the 
night by the indications of a thermometer suspended in a free atmosphere. Tlje 
plant may be strongly frozen, although the air remaius constantly several degrees 
above the freezing point. In the nights of April and May, the temperature of 
the atmosphere is frequently only four, five, or six centrigrade degrees above 
Zero. When this happens, plants exposed to the light of the moon, that is, to a 
clear sky, may be frozen, notwithstanding the indications of the thermometer. 
If the moon on the contrary does not shine, in short, if the sky be cloudy, the 
temperature of the plants does not fall below that of the atmosphere, and they 
will consequently not be frozen, unless the thermometer indicates Zero. It is, 
therefore, quite true that a plant may be frozen or not, according as the moon 
be visible or concealed behind clouds. The moon’s light is, in this case, only 
the index of a clear atmosphere, and it is in consequence of the clearness of the 
sky that the nocturnal congelation of plants takes place; the moon contributes 
to the effect in no way whatever, for although she might be hid under the 
horizon, the effect would not be different.—M. Arago. — Field’s Nat. Mag. 
Microsetia ruficapitella. —In the autumn, the leaves of the rose-tree, on 
their upper surfaces, are very often marked in various directions with broad 
brown lines, having a narrow black one running down the middle. This curious 
appearance is caused by the small caterpillar of a minute moth (Microsetia) 
which feeds inside the leaf when full grown, the caterpillar is nearly two lines 
long, of a yellow-orange colour with a brown mark down the back, the head very 
flat, and sharp, and light chocolate. The brown mark on the leaf is caused by 
the drying of the epidermis, from the insect having eaten the parenchyma, or 
substance of the leaf beneath. The black one is caused bv its egesta which, 
during its young state entirely stop up the mine. When full grown, which is 
