220 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
Latent Life of Seeds.* — Pursuing his experiments on this subject, 
M. 0. de Candolle finds that if seeds of maize, oat, fennel, Mimosa ]?u- 
dica, Gloxinia , and other plants, are exposed for 118 days to a tempera- 
ture of — 40° F., the majority will still germinate. The protoplasm of the 
seeds is described as not actually living, but as having reached a stage 
of inaction in which it is still endowed with potential life. 
Changes in the Tentacles of Drosera produced by Feeding-! — 
Miss L. Huie describes the remarkable changes produced in the cells of 
the tentacles of Drosera rotundifolia by feeding the leaves with white of 
egg. As the result of this stimulation the basopliile cytoplasm is used: 
up, and is represented ultimately by a very scanty eosinophilous plasm. 
The restoration of the cytoplasm is brought about by the nucleus absorb- 
ing food-material, and then excreting it into the protoplasm. 
Temporary Suspension of the Action of Chlorophyll.! — Prof. W. 
Pfeifer calls attention to the arrest of the assimilating function of chlo- 
rophyll-grains under unfavourable vital conditions, or through the action 
of reagents, which is only temporary, if these conditions last but for a 
short time. During this period they undergo no change of form or 
colour ; respiration becomes feeble, but is not entirely suspended. Iso- 
lated chlorophyll-grains can assimilate for a time when exposed to 
light. 
(3) Irritability. 
Mechanism of the Phenomena of Sensitiveness. § — Prof. A. Borzi 
sums up as follows his conclusions as to the mechanism of the motile 
phenomena resulting from a blow or from sharp concussion. 
The cause lies in special protoplasmic elements, differentiated physio- 
logically as organs for the reception and transmission of the irritation. 
They consist of very delicate fibres, and in general of cells arranged in 
longitudinal rows in the direction followed by the irritation, and consti- 
tute definite anatomico-physiological plexi. The cells have a very thin 
membrane which is very contractile, and is endowed with well-marked 
osmotic properties. Minute perforations, adapted for the passage of 
very fine protoplasmic threads, often traverse their walls. The action 
of stimuli which induce variations in the state of imbibition of the proto- 
plasm is followed by a rapid change in the turgor and tension of the 
cells, thus changing the position of the irritated organ. For the purpose 
of retaining temporarily the water expelled from the protoplasm during 
the variation in its osmotic condition, every sensitive plexus is traversed 
by intercellular spaces, which form a connected system, varying in its 
special character in different cases. Occasionally the median layer of 
the membrane of the sensitive cells is transformed into a semi-fluid sub- 
stance, and forms a receptacle for water. The gelatinisation of this layer 
sometimes fills the spaces with an absorbent colloidal substance. The 
rapidity with which the sensitive plexi respond to the action of stimuli 
depends on the presence of this substance, and on its density. The 
water which fills the intercellular spaces contains various organic sub- 
* Rep. 66th Meeting Brit. Ass., 1896, pp. 1023-4. Cf. this Journal, 1895, p. 655. 
t Quart. Journ. Micr. Sci., xxxix. (1897) pp. 387-425 (2 pis. and 1 fig.), 
j Ber. K. Sachs. Ges. Wiss. Leipzig, June 1st, 1896. See Bot. Centralbl., Ixix. 
(1897) p. 72. § 11 Naturalista Siciliano, i. (1897) pp. 168-90. 
