190 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
(2) Other Cell-contents (including- Secretions). 
Formation of Secretions.* — Dr. A. Tscbirch ascribes to all resins 
a uniformity in chemical composition, regarding them as compounds 
of aromatic acids with a peculiar group of alcohols which he calls 
resinols. 
The author further announces the remarkable discovery that, in all 
normal cases which he has been able to examine, the formation of a 
secretion is a function of the cell-wall and not of the protoplasm. In 
schizogenous passages the secreting cells which clothe the canal contain 
a resinogenous layer, often of a vacuolar character ; in schizo-lysigenous 
cavities the secretion is formed in peculiar caps of membrane belonging 
to the cells which enclose the space ; in the oil-glands of the Labiatse, 
Composite, &c., it is produced entirely in a subcuticular layer of the 
cell- wall ; and this is the case also with the papillae which project into 
the intercellular spaces of the rhizome and base of the leaves of Nephro- 
dium Filix-mas , and in many, if not in all, extra-floral nectaries, the 
secretion lifting the cuticle off from the palisade-like secreting tissue. 
In all stigmas examined by the author the secretion is formed in the 
subcuticular mucilaginous layer of the papillae, into which the pollen- 
tube makes its way. Similar observations were made on the oil of 
oil-glands, and on the resin formed in duramen. But, although the 
secretions are formed in the cell-wall, they are never produced by meta- 
morphosis of the cellulose itself. 
Formation of Secretions in Schizogenous Receptacles.f — Herr A. 
Becheraz has studied this subject, especially in the elongated receptacles 
in the Abietineae, Compositae, Umbel! iferae, Burseraceae, Clusiaceae, &c. 
He finds the secretion to be present in these receptacles from the earliest 
stages of their formation; none is contained in the cells of the sur- 
rounding tissue. Besin could never be detected outside the resin- 
passages. A group of cells, early distinguished by their colourless 
contents, arising from the mother-cell of the canal, forms a coating of 
mucilage where these cells bound the epiderm, and this mucilage con- 
tains the resinogenous substances. The extent to which the canal is 
ultimately filled with resin varies greatly. A membranous structure, 
the inner pellicle, is formed at the point of contact of the resin with the 
layer from which it springs, and often contains granules of various 
kinds. 
Influence of the Soil on the Production of Hectar.J — According 
to M. G. Bonnier the production of honey or nectar in plants is greatly 
influenced by the nature of the soil. Thus Sinapis alba produces a much 
greater quantity on a calcareous than on an argillaceous soil ; Polygonum 
Fagopyrum more on a siliceous than on a calcareous soil. An argillaceous 
soil is favourable to the production of honey in Phacelia tanacetifolia , a 
calcareous soil in Isatis tinctoria and Medicago saliva. Onobrychis saliva 
is nearly indifferent to the nature of the soil. 
* Bot. Centralbl., lx. (1894) pp. 289-93. Cf. this Journal, 1894, p. 372. 
f Mtthl. Naturf. Gesell. Bern, 1893 (1894) pp. 74-109. See Bot. Centralbl., lx. 
1894) p. 20. 
t C.R. Ass. Fran<j. pour l’Avance. d. Sci., 1893 (1894) pp. 567-9. See Bot. Cen- 
tralbl., 1894, Beih., p. 419. 
