1S78.] 
PLANT-GROWTH IN DARKNESS.-THE ABEC AND EARLY PURPLE PEACHES. 
181 
the inner circumference for the heating of the 
atmosphere as it ascends. The pipes or tubes are 
thus kept at the same high temperature with a 
considerably less quantity of water, thus heat¬ 
ing the air more rapidly as it ascends through 
their inner circumference. A rapid and con¬ 
tinuous circulation is also maintained, by means 
of an outer pipe or tube connected with the 
body at its lowest point and highest centre, 
upon which is attached a chamber to allow 
for expansion; and by means of a short 
tube placed vertically therein, and passing 
through it at its base, and rising above the 
water-level, a current of air is allowed to 
ascend, which, coming in contact with the 
steam, condenses it more rapidly, thus pre¬ 
venting any waste of water and the possibility 
of the upper tube becoming empty; this also 
acts as an overflow, in case too much water 
has been put in. 
Usually petroleum or one of the mineral oils 
is used ; but when gas is burnt, a chamber 
partly filled with water is so placed that the 
whole of the burnt or hot air given off in 
combustion is conducted over the surface of 
the water, by which it becomes purified, so 
that it is not either injurious to health or 
vegetation. This can also be had fitted to the 
petroleum stove, if desired. These stoves can 
be made in any size or shape.—M. 
PLANT-GROWTH IN DARKNESS. 
rjgNKOFESSOR RAUWENHOFF has re¬ 
cently published in the Archives Ne'er - 
landaises the results of his researches 
into the causes of the abnormal development 
of plants growm in darkness, of which the 
following is a summary :— 
“ The abnormal elongation of stems is partly 
to be attributed to an excessive growth of 
the pith, combined with an imperfect develop¬ 
ment and slight thickening of the elements of 
the vascular bundles. The anatomical differ¬ 
ence between green and blanched stems is 
especially apparent in the slight thickening of 
the walls of the epidermal, woody, and liber 
cells, in the number and radial dimensions of 
the vascular bundles, the absence of the sheath 
in the vascular bundles of monocotyledons, and 
the relatively greater development of pith. 
The defective thickening of the cell-walls is 
not, as has been supposed, due to the absence 
of the colouring matter of chlorophyll, because 
the walls of the pith-cells are often very thin. 
Moreover, the parenchymatous cells of the 
bark and epidermis sometimes attain an extra¬ 
ordinary size. The preponderating influence 
of the pith is, however, not the sole cause of this 
abnormal elongation, since it is also traceable to 
other sources, including the whole fundamental 
tissue collectively—to the bark as well as to 
the pith, since hollow stems also exhibit this 
extraordinary elongation in darkness. The ver¬ 
tical position of blanched stems is determined 
by the absence of heliotropism. 
“In a word'the anomalies presented by stems 
growm in the dark are the effect of negative 
geotropism, uninfluenced by heliotropism, and 
favoured by the slight thickening of the cell- 
walls ; because growth, that is to say, the 
division and enlargement of cells, is not 
dependent on the presence of light, but pro¬ 
ceeds, often by preference, in the dark; 
because negative geotropism acting on a stem 
in active growth induces vertical elongation; 
and because heliotropism retards growth, as 
inflection is the consequence of feebler longi¬ 
tudinal growth on the side turned towards the 
light. The cause of the inequality exhibited 
by different plants with regard to elongation 
in the dark is probably owing to diverse 
degrees of turgescence of the cells, and the 
relative tension of the tissues. Etiolated leaves 
differ anatomically from green leaves of the 
same size not only in the absence of chlorophyll 
and starch—except in the cells of the stomates, 
which always contain abundance of starch—• 
but also in the slight thickening of the walls 
of the vascular tissue, and especially in the 
non-development of spongy parenchyma.” 
THE ABEC AND EARLY PURPLE 
PEACHES. 
)HEN planting fruit-trees of any kind, 
it is of the greatest importance to 
have the varieties true to name ; but 
it sometimes happens that we may get varieties 
the very opposite of what have been ordered, or 
desired—early kinds turning out to be late, and 
vice versa. This is a state of things one must 
make the best of when the mischief is done. But 
it sometimes happens that one is advised to 
plant new fruits, not proved, and also to give 
others a trial which have proved to be all that 
can be desired elsewhere. I have more than 
