ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
207 
majus ; endosperm of Lilium Mar tag on, Fritillaria imperialis, and Hor- 
deum vulgare ; root of Ranunculus asiaticus ; leaf-stalk of Tamus com- 
munis, Viscum album, Marattia elegans, Aucuba japonica, Prunus Lauro- 
cerasus, Neriurn Oleander, Lilium Martagon, L. candidum, Salisburia 
adiantifolia , Asplenium rutsefolium ; flower-stalk of Taraxacum dens- 
leonis ; pulvinus of Mimosa sensitiua, Robinia Pseudacacia ; tendril of 
Cucurbita Pepo. 
Tensile Strength of Cell-walls.* — From experiments made on vari- 
ous vegetable fibres, Mr. H. N. Dixon concludes that the tensile strength 
of cell-walls is very much more than sufficient to resist the osmotic 
pressure of the cell-sap, which frequently ranges between 20 and 30 
atmospheres. In the cases experimented on there was a coefficient of 
safety varying between 14 and 25. The tenacity of cellulose is stated to- 
be greater than 50,000 grs. per sq. mm. 
(2) Other Cell-Contents (including: Secretions). 
Proteolytic Enzymes of Nepenthes.l — Prof. S. H. Vines has made 
a careful examination of the fluid secreted by the pitchers in several 
species of Nepenthes, especially N. Mastersiana, and has determined 
that its digestive powers are due to the action of a true proteolytic 
enzyme in the presence of an acid, and not to the presence of bacteria. 
He states that the liquid will digest fibrin in the presence of 1 per cent, 
hydrocyanic acid, and that it is possible to prepare active glycerin- 
extract from the pitcher-tissue. The enzyme is clearly allied to the 
peptic group, and is apparently tryptic in its action. The proteid- 
product of digestion appears to be not peptone, but deutero-albumose. 
One peculiarity of the enzyme is its great stability ; it is antiseptic, and 
resists decomposition. 
“Encapsuling” of Starch-grains. — Prof. L. Macchiatif gives ad- 
ditional reasons for doubting Buscalioni’s statement with regard to the 
“ encapsuling ” of starch-grains in the integument of the seed of Vicia 
narbonensis. 
In reply Dr. L. Buscalioni § adduces the opinion of various distin- 
guished Italian botanists in favour of his view. 
Sorghin and Sorghorubin.|| — Sig. N. Passerini has extracted from 
the red-spotted leaf-sheaths of Sorghum vulgare and saccharatum, and of 
Zea Mays, a pigment which he terms sorghin , which is, however, a 
product of transformation of the natural pigment sorghorubin. The red 
colour of the spots is due, in the first place, to this pigment, and not 
directly to bacteria, as has been stated. 
(3) Structure of Tissues. 
Development of the Growing Point in the Stem of Monocotyle- 
dons. — From the study of a number of species belonging to several 
different orders of Monocotyledons, M. J. Baranetzky states that a very 
characteristic feature is the presence in the growing point of one or 
* Ann. of Bot , xi. (1897) pp. 585-8. t Tom. cit., pp. 563-84. 
x Bull. Soc. Bot. Ital., 1897, pp. 268-71. Cf. this Journal, 1S97, p. 544. 
§ Tom. cit., pp. 303-10. Malpighia, xi. (1898) pp. 469-90. 
|| Tom. cit., pp. 195-7. 
If Ann. Sci. Nat. (Bot.), iii. (1897) pp. 311-65 (3 pis.). 
