ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
413 
growth in length, due to the curtailment or elongation of the inter- 
nodes of the stem, rarely ( Colchicum ) to the lateral extension of the 
underground organ itself. It is influenced by the depth of covering of 
soil ; a slight covering inducing descent, a thick covering ascent. The 
phenomenon cannot be explained by heliotropism or aerotropism. 
Germination and Parasitism of Ximenis. — M. E. Heckel * has 
noticed a peculiarity in the germination of the seeds of Ximenia ameri- 
mna , belonging to the Olacacese. On the hypocotyl are produced five 
scales, preceding the true leaves ; of these the lowermost pair penetrate, 
in the manner of roots, into the trough formed by the petioles of the 
cotyledons, and become united with the tissue of the cotyledons at the 
base of their laminae. The author suggests that they may possibly uct 
as organs of absorption. 
In a second communication, f M. Hcckol states that the roots put out 
suckers, each root or branch of a root ending in a sucker, and that by 
means of these organs a parasitic attachment is secured to a root or 
stem ; this attachment taking place to a stem of the same species where 
no other is available. This parasitic character seems to indicate an 
affinity between the Olacaceas and the Santalaceae. 
Germination of Neottia Nidus-avis.J — M. N. Bernard believes the 
presence of a mycorhiza to be necessary to the germination of seeds of 
the bird’s-nest orchis. 1’his mycorhiza attacks all the moist parts of the 
plant, even the ripe seed-vessels, and the seeds will germinate while 
still enclosed within the fruit. The moist rhizomes and other under- 
ground parts are especially infested by the mycorhiza, which may be 
absent from the dry parts above the surface. 
(3) Irritability. 
Irritation-Movements in Biophytum. — Dr. G. Haberlandt § re- 
cords the results of some experiments on the irritation-movements in 
the leaves of Biophytum sensitivum , and the transmission of the irrita- 
tion ; the most important being the repetition of the reaction-movement 
in response to a single irritation. From the phenomena of the reaction 
he concludes that the irritation is conducted through the parenchyme of 
the vascular bundles by means of protoplasmic connections from cell to 
cell. 
Prof. D. T. McDougal || points out the discrepancy between these 
observations and his own.l 
C4) Chemical Changes (including Respiration and Fermentation). 
Primary Synthesis of Proteids in Plants.**— Mr.W. M. Kozlowski 
discusses this subject at considerable length from a chemical point of 
view, lie considers a large part, if not all, of the oxalic acid produced 
in plants to be a final product of decomposition of proteids, and in a 
certain degree, to be analogous to carbamide in animals ; it appears to 
be always an excretory product. There is a strong analogy between 
* Bull. Soc. Bot. France, xlv. (1899) pp. 438-41. 
f Comptes Rendus, cxxviii. (1899) pp. 1352-3. J Tom. cit., pp. 1253-5. 
§ Ann. Jard. Bot. Buitenzorg, Supp. ii. 1898, pp. 33-8. 
|| Bot. Centralbl., lxxvii. (1899) pp. 297-8. 
Cf. this Journal, 1897, p. 143. 
** Bull. Torrey Bot. Club, xxvb (1899) pp. 35-57. 
