ZOOLOGY AND BOTANY, MICBOSCOPY, ETC. 
351 
Solanine was found in nine species of Solanum and three of Scopolia. 
In the vegetative organs it occurs in greatest abundance in the young 
tissues, and in the mature parts is usually entirely absent. In the floral 
organs, on the other hand, it continues to increase up to a certain period, 
and is especially abundant in. the peripheral layers of the unripe fruit. 
Its seat is in the cell-cavity, where it occurs in the form of a soluble 
salt, and from which it penetrates also to the cell-wall. 
The author regards solanine as a product neither of primary 
synthesis nor of disorganization, nor as a secretion or excretion, nor as 
a reserve-substance, nor as a transporting form like asparagin, but as an 
intermediate stage in the series of chemical changes which already- 
formed plastic substances undergo in the living cell. In the flowers 
and unripe fruits it undoubtedly also serves as a protection against 
consumption by animals. 
Allium-Oil.* — Herr A. Voigt finds allium-oil or allyl-sulphide 
[C 3 Hg] 2 S as an ethereal oil in all parts of various species of Allium, 
viz. in the stem, leaves, bulb-scales ; both in the epiderm and the 
bundle-sheath, viz. in the bundle-sheath of the floral organs ; in the 
outer endoderm and root-cap, in the root, the fruit, and the integument 
of the seeds ; in the layer of the endosperm immediately surrounding 
the embryo. It is present at all periods of growth, and has apparently 
been formed in the process of metastasis. The author regards its 
physiological purpose to be mainly as a protection against the attacks 
of animals ; but its presence in the vascular bundle-sheath also serves 
to secure a path for the conduction of water and plasmic substances. 
Amount and Composition of Ash.f — Prof. C. Councler gives par- 
ticulars of the proportion of ash found in the dried material from a 
number of herbaceous and woody plants, the amount varying from 
15*35 p. c. in Adonis sestivalis, to 1*35 p. c. in the pine, and as low as 
1*08 p. c. in branches of the same tree on which the mistletoe was 
parasitic, the mistletoe itself containing, in different organs, from 3*49 
to 8*11 p. c. of ash. The percentage composition of the ash is also 
given in the difierent species; the mistletoe withdraws from its host 
especially large quantities of potassium salts and phosphates. 
C3) Structure of Tissues. 
Liber of Angiosperms.J — M. H. Lecomte has made an exhaustive 
examination of the structure and development of the liber in the stem 
and leaves of the vine, lime, gourd, and many other woody and herbaceous 
plants. The following are the more important results : — 
The liber of Angiosperms comprises two classes of elements — the 
essential (sieve-tubes and companion-cells) and the accessory elements 
(liber-parenchyme, sclerotized cells, and liber-fibres). The fibres sur- 
rounded by liber almost always differ in their histological and micro- 
chemical properties from those of the fibre outside the liber. The 
liber-parenchyme is often composed of elongated cells (fibres), simple or 
* ‘ Lokalisirimg d. sether. Oeles in d. Geweben d. Allium-Avten" Hamburg, 1889, 
8vo, 18 pp. See Bot. Centralbl., xli. (1890) p. 292. 
t Bot. Centralbl., xl. (1889) pp. 97-100, 129-33. 
i Ann. Sci. Nat. (Bot.), x. (1889) pp. 193-324 (4 pis.). 
