14 i SUMMARY OF CURRENT RESEARCHES RELATING TO 
served. A fresli series of experiments on Mimosa pudica and Oxalis 
sensitiva confirm his previous statement that the irritation is not trans- 
mitted through the vesicular cells, and lead to the following conclusions. 
Impulses may be transmitted through dead portions of stems or petioles 
in which the conditions are such that a transmission by the cell- wall or 
the water in the wall only is possible. Great variations in the pressure 
exerted on portions of the plant in such manner as to set up hydrostatic 
disturbances extending throughout the entire plant are not followed by 
reactions ; hydrostatic disturbance, therefore, does not constitute an 
impulse. 
Irritability of Catasetum.* * * § — Mr. J. H. Hart contests Darwin’s state- 
ment of the irritability of the flowers of Catasetum tridentatum. He states 
that the ejection of the pollinia can be caused by other means than the 
irritation of the “ antennas ” by insects ; a concussion of the flower, the 
removal of the anther-cap, or pressure exerted on almost any part of the 
column, and especially any irritation on the margins of the stigmatic pit, 
will effect this readily if the flower is at a favourable stage of maturity. 
The expulsion of the pollen does not depend on any special irritability, 
but on mechanical action alone. The “ antennae ” are merely a pro- 
longation of the edges of the stigmatic pit. When the flower opens, they 
become turgid, stiff, and non-elastic. In this state they furnish levers 
which are amply sufficient to cause a disturbance of the grip they hold on 
the margin of the caudicle. 
Gamotropic and Carpotropic Movements of the Flowers of 
Grasses.! — Prof. A. Hansgirg finds a common type of these movements 
to be that displayed by Avena, in which the flowers, which are closely 
crowded together in the bud-condition, become widely separated from 
one another before flowering by the curving of the flower-stalk or of the 
axis of the raceme or panicle. After flowering, the ripening fruits may 
either remain in the same position, or may revert to that which the buds 
occupied before flowering. A large number of species are mentioned in 
which the carpotropic movements are especially conspicuous. 
Phyllocarpy.J' — By this term, Prof. A. Hansgirg proposes to desig- 
nate the movement which takes place of the flower-stalk, after flowering, 
in many climbing plants ( Tropseolum , Cobsea, &c.), by which the ripening 
fruit is hid in the foliage for its better protection. 
(4) Chemical Changes (including Respiration and Fermentation). 
Formation of Proteids from Asparagin.§ — By a series of experi- 
ments, chiefly on Lemna, Herr B. Hansteen has determined that when 
asparagin and grape-sugar occur together in the same cell, they combine 
rapidly, the result being the formation of proteids. If, however, the 
grape-sugar is replaced by cane-sugar, no considerable chemical combi- 
nation takes place. The contrary is the case with glycocoll ; with grape- 
sugar, this amide is inactive, while with cane-sugar, an abundant forma- 
* Bull. Misc. Inform. R. Gard. Trinidad, ii. (1896) p. 225. See Bot. Gazette, 
xxii. (1896) p. 505. 
t Oesterr. Bot. Zeitschr., xlvi. (1896) pp. 320-5. Cf. this Journal, 1893, p. 69. 
X Oesterr. Bot. Zeitschr., xlvi. (1896) pp. 401-2. 
§ Ber. Deutsch. Bot. Gesell., xiv. (1896) pp. 362-71. 
