ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
135 
character, and appears to be identical with the substance of mucilage. 
In schizo-lysigenous oil-passages, like those of the Rutaceae, there is first 
a cap-like formation of the resinogenous layer, followed by a dissolution 
of the cells, and a resorption of the protoplasm. 
Encapsuling of Starch-Grains.* * * § — In the lowest of the three layers 
which Macchiati describes f as constituting the testa of the seeds of Vida 
narbonensis — a description which applies equally to the seeds of all 
Leguminosae — Dr. L. Buscalioni finds starch-grains which display the 
curious phenomenon of encapsulation. Some of the cells of this tissue 
contain single starch-grains of colossal size, while in others are a number 
of much smaller grains. Connecting these grains with the protoplasm 
in which they lie is a ring composed of a substance coloured brown by 
tannin, consisting of short rods placed perpendicularly to the plane of 
the ring. This peculiar membrane is formed with great rapidity. A 
similar phenomenon, but not so well marked, was observed in the seeds 
of Eschsclioltzia californica. 
Peculiarity of Soluble Starch4 — Prof. W. Beijerinck remarks that 
soluble starch in aqueous solution will not mix with an aqueous solution 
of gelatin even at boiling heat. When the two are shaken together an 
emulsion is formed — an emulsion of gelatin droplets in starch solution. 
The gelatin droplets in their turn contain very minute starch droplets, 
as may be shown by treatment with iodine and microscopical inspection. 
It is quite possible that this observation may lead the way to new 
researches and new views as to the nature of colloidal bodies. 
Reserve-Stores of Seeds.§ — M. E. Couvreur finds that during the 
ripening of the seeds of Pidnus, the stores of oil and starch have a 
parallel increase. Even when separated from the plant, the seeds show 
for a time an increase in reserves, the increase of oil and starch being 
still parallel. The author compares this to the increase of glycogen 
within the silkworm chrysalis. During germination, the starch dis- 
appears very rapidly, the oil much more slowly. 
Arrow-Poisons. || — Herr L. Lewin gives a detailed account of the 
source of the various poisons used for arrows. The order from which the 
greatest number are derived, is the Apocynaceae ; next follow the Legu- 
minosae, Loganiaceae, and Euphorbiaceae. Among the Apocymaceae, the 
most important poisons are obtained from the genera Adenium , Aco- 
hanthera , and StropJianthus ; of Leguminosae, the genera Erythrophloewn 
and Physostigma supply the most important poisons. Antiaria toxicaria 
(Moraceae), Pothos (Araceae), Aconitum , and Helleborus also yield im- 
portant arrow-poisons. 
(3) Structure of Tissues. 
Influence of Fruit-bearing on the Development of Mechanical 
Tissue.lF — Mr. A. J. Pieters has made a series of experiments on this 
* Malpighia, x. (1896) pp. 479-89 (1 pi.). 
t Cf. this Journal, 1892, p. 63. 
t Centralbl. f. Bakteriol. u. Parasitenk., 2 te Abt., ii. (1896) pp. 697-9. 
§ Ann. Soc. Linn. Lyon, xlii. (1896) pp. 145-8. 
H ‘Die Pfeilgifte,’ Berlin, 1894, 152 pp. See Bot. Centralbl., Ixviii. (1896) 
p. 328. 1 Ann. Bot., x. (1896) pp. 511-29. 
