112 Chronicles of Science. | Jan. 
the anther tube rises to about four millimetres above the extreme 
points of the corolla, and if the same be touched, pollen, in lumps, 
issues from the summit, the anther-tube at the same time undergoing 
a remarkable twisting. After a short interval this is repeated. The 
style gradually becomes elevated above the summits of the anther- 
tube, and by the time it projects about four or five millimetres beyond, 
the irritability has completely disappeared, having lasted at the most 
about twenty-four hours. When the styles are visible it is too late 
for instituting experiments. These phenomena are produced solely 
by the contraction of the filaments of the stamens, which on each touch 
instantly contract, and after a little, resume their former length. The 
expulsion of the pollen depends upon the anther-tube being drawn 
downwards upon the style by the contracting filaments, and then pushed 
up again. 
The subject of the functions of vascular tissue causes some difference 
of opinion among botanists, some saying that although containing air 
at most seasons, they are filled with sap in spring, while others affirm 
that when once formed they contain only air. M. Gris has applied 
Fehling’s solution, which deposits a red precipitate when boiled with 
avery small quantity of glucose, thus indicating the presence of an 
essential element of the sap. On plunging for a few moments into 
such a boiling solution, thick fragments of the wood of chestnut, beech, 
poplar, laburnum, &c., at the commencement of spring, and afterwards, 
cutting thin sections for the microscope, the precipitated oxide of 
copper is found clothing the inner face of the large vessels, and form- 
ing reddish threads visible to the naked eye. 'The precipitate is also 
abundant in the cells of the medullary rays, whence M. Gris concludes 
that the so-called lymphatic vessels (at all events in spring) contain a 
sap either identical with, or closely analagous to, that found in the 
cellular elements of these stems. The spiral fibres of the reticulated, 
annular and spiro-annular, and other similar vessels of herbaceous 
plants, also present, in their interior, the red precipitate when similarly 
treated. 
With regard to one class of vessels concerning which very con- 
siderable modification of opinion has been necessary since their first 
discovery by Schultz, viz. the laticiferous tissue, M. Lestiboudois has 
instituted a systematic series of experiments, the results of which he 
communicates from time to time to the ‘Comptes rendus.’ He has 
established beyond doubt the existence, in certain plants, of vessels 
containing coloured liquids, and that these vasa propria are not mere 
excavations in the tissue, permeated by a thread of granuliferous tissue, 
but that, though probably at a late period, a delicate wall is developed, 
which constitutes it a distinct vascular system, though notin all points 
a counterpart of that of the blood-vessels of animals; nor do they fulfil 
precisely the same purpose. While not, however, regarding the contrac- 
tility of these vessels as proved, he considers that he indisputably 
makes out a circulation of the liquid contents, not regularly from one 
point to another, but in such a manner that the granules are driven 
into all the ramifications of a more or less complicated network. In 
