218 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
(4) Chemical Changes (including Respiration and Fermentation). 
Emptying of the Contents of Reserve-Receptacles.* — Herr K. Purie- 
witsch has investigated this subject in detail, especially in relation to the 
endosperm of grasses. In a long series of experiments he found the 
consumption of the food-materials to take place in all cases without the 
introduction of any enzyme from outside. The author considers it as 
proved that the endosperm of grasses and other plants is a living organ 
in which each individual cell has the power of forming diastase indepen- 
dently of the embryo and scutellum. The same conclusion was arrived 
at with respect to cotyledons, bulbs, roots, and rhizomes, whenever the 
conditions are such that the resulting products of dissolution can be 
carried away. 
The emptying of the reserve-receptacles is promoted by a rise of 
temperature. In the case of objects which do not contain chlorophyll, 
light appears to produce no effect. The products of the processes which 
take place are chiefly carbohydrates ; but the exact composition was 
difficult to determine owing to the very small quantities produced. 
Digestion of the Endosperm of the Date.j* — M. Leclerc du Sablon 
confirms, in the case of the date, the accepted statement that the endo- 
sperm does not itself produce any diastase capable of digesting its food- 
materials ; and moreover, that the diastase supplied by the cotyledon 
which attacks the cellulose does not penetrate into the endosperm. Its 
action is confined to those portions where the endosperm and the coty- 
ledon are in contact ; it is only the diastase which gives rise to the 
production of fatty acids that passes from the cotyledon into the endo- 
sperm, and commences the digestion of its oily substances. The reserve 
food-material of the endosperm is contained entirely in the very thick 
cell-walls composed of cellulose ; in the interior of the cells is a small 
quantity of oil and of aleurone mixed with protoplasm. 
Oleaginous Reserve-Substances of the Walnut.J — M. Leclerc du 
Sablon finds the general course of digestion of the oil to be the same in 
the walnut as in other oily seeds. It displays also a similar increase in 
acidity during germination. Glucose, the assimilable form of carbo- 
hydrate, is always found in the seed when in a state of activity, but is 
wanting in the dormant condition. The quantity of saccharose, on the 
other hand, is continually increasing ; it forms a reserve-material in 
the ripe seed ; during germination it is digested and transformed into 
glucose. It is, in fact, an intermediate substance between oily matters 
and glucose. 
Enzyme of Barley.§ — Herr F. Reinitzer does not find in germinating 
barley the cytase stated to occur there by Browne and Morris. The 
diastase of germinating barley has the power of easily dissolving hydro- 
lytic hemi-eelluloses, which are abundantly distributed in plants. But 
there are numerous hemi-celluloses which are not attacked by diastase. 
Seeds in which these are stored up as reserve-substances probably pro- 
duce in germinating a peculiar enzyme which may be called cytase. 
* Jahrb. f. wiss. Bot. (Pfeffer u. Strasburger), xxxi. (1897) pp. 1-76. 
t Rev. Gen. de Bot. (Bonnier), ix. (1897) pp. 395-8. J Tom. cit., pp. 313-7. 
§ Hoppe-Seyler’s Zeitschr. f. Phys. Chemie, xxiii. (1897) pp. 175-208. See 
Oesterr. Bot. Zeitschr., xlvii. (1897) p. 303. 
