21S 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
Localization of the Active Principles in the Capparideae, Tro- 
paeoleae, Limnantheae, and Resedaceae.* * * § — M. L. Guignard finds my- 
rosin to be widely distributed in all these natural orders. 
In the Capparide® ( Capparis , Cleome, Polanisia, Gynandropsis) 
special ferment-cells containing myrosin are general in the root and 
stem ; their morphological characters resemble those of the Crucifer®. 
They are most abundant in Capparis, as is also the glucoside which they 
decompose ; they occur especially in the flower and in the pulp of the 
fruit. In all Capparide® the seed contains but a small quantity either 
of the ferment or of the glucoside, and the ferment is localized in the 
embryo. 
In the Trop®ole® ( Tropseolum) and Limnanthe® ( LimnantJies Dou- 
glasii ) all the organs contain myrosin ; but the essence (a nitrile) does 
not exist in any of the tissues, and can be formed only by the action of 
the ferment. 
In the Resedace® ( Beseda odorata and lutea) the author finds myrosin 
to be present not only in the aerial organs, but also, in opposition to 
the observation of Spatzier,f in the root ; in the stem it occurs in the 
cortical and liber-cells, as well as in the guard-cells of the stomates. 
Its presence in the root can be proved by macerating in water, leaving 
the mixture exposed to the air for some hours at a temperature of about 
50° C., and evaporating. If the residue is then treated with water to 
which potassium myronate is added, a strong odour of essence of mustard 
is given off, demonstrating the decomposition of the glucoside by myrosin. 
That the essence of mustard does not occur as such in the root can be 
proved by treating with boiling absolute alcohol, which would dissolve 
out the essence if it were present. 
(3) Structure of Tissues. 
Influence of Lignification on the Life of the Cell. J — Herr 0. 
Warburg refers to the cases in which it has been shown that cells the 
walls of which have become lignified, are still in a vital condition, and 
capable of segmentation, and discusses the question whether a produc- 
tion of meristem can take place from such cells. In opposition to the 
statement of some previous observers, he asserts that this is not the case. 
The new formations which take place in the woody tissue of climbing 
plants always proceed from the unlignified cells, which are intercalated 
among the lignified. Thin-walled tissue can be formed from the lignified 
cells of medullary rays only when the protoplasts have lost their 
lignified coating as the result of gummosis. 
Characteristics of Duramen. § — Prof. R. Hartig has carefully ex- 
amined the differences in the structure of different parts of the trunk 
of the oak ( Quercus pedunculata ), some of the trees being as much as 
400 years old. The formation of the annual ring begins about April 
20th, and is completed in the lower part of the trunk by the middle of 
August, in the upper portion by the beginning of September. The 
* Journ, de Bot. (Morot), vii. (1893) pp. 345-64, 377-82, 393-400, 444-60 (18 figs.), 
and Comptcs Rendus, cxvii. (1893) pp. 493-6, 587-90, 751-3, 861-3. Cf. this 
Journal, 1891, p. 362. t Cf. this Journal, ante , p. 76. 
t Ber. Deutsch. Bot. Gesell., xi. (1893) pp. 425-41 (3 figs.). 
§ SB. Bot. Ver. Miinchen, Nov. 13, 1893. See Bot. Centralbl., lvi. (1893) p. 357. 
