404 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
has a bipolar origin. Three types are described of the arrangement of 
the chromatin substance within the nucleus. The direction of the 
first divisions of the nucleus also varies. Centrosomes do not occur 
either in dividing or in resting cells. 
In another paper * * * § the same author treats of various abnormal modes 
of nuclear division in the same object. 
( 2 ) Other Cell-contents (including 1 Secretions). 
Cytological Changes produced in Drosera.f — Continuing her ob- 
servations on the changes produced in the tentacles of Drosera by 
feeding with various food-materials, Miss Lily H. Huie states that very 
characteristic alterations result, both in the staining reactions and in 
the morphology of the cell. In five seconds, white of egg causes' both 
the cytoplasm and the nuclear plasm to become more eosinophil, while 
pure amphopeptone increases their affinity for blue stains. White of 
egg quickly causes great impoverishment of cytoplasm and nuclear 
plasm, while the first effects of pure peptone are to increase their bulk 
and density. Both produce an enormous increase of the chromatin 
element of the nucleus. While the cytoplasm is the cell-constituent 
most rapidly and most constantly affected by external stimuli, the 
nucleus is the seat of metabolic activity, and the state of the nuclear 
structures indicates whether or not the food supply was of service to the 
metabolism of the plant. The results of feeding with a number of 
different food-materials are given in detail. 
Production of Pure Chlorophyll.^ — Dr. G. Bode describes a com- 
plicated process by which he obtains pure chlorophyll or its potassium 
salt from green leaves. He emphasises the fact that an acid reaction 
of alcohol, even if only slight, decreases its power of dissolving chloro- 
phyll, as contrasted with benzin ; an alkaline reaction having an opposite 
effect. He points out the errors that have resulted from confusing 
between benzin and benzol, two substances which have nothing to do 
with one another, except the similarity in their names. 
Red Cell-sap of Plants.§— Mr. E. Overton found that, by cultivating 
Hydrocliaris morsus-ranse in a weak solution of sugar, the leaves assume 
a rich reddish-brown colour, though otherwise perfectly normal. Similar 
results were obtained with several species of Utricularia, and with some 
land plants, as Lilium Martagon, L. candidum , L. umbelliferum, Ilex 
aquifolium , and Saxifraga crassifolia , but not with Lemna minor or 
Potamogeton perfoliatus. 
The appearance of a red cell-sap is, in most plants, closely con- 
nected with the amount of sugar in the sap ; its formation is 'greatly 
favoured by a low temperature ; it is comparatively rare when the tem- 
perature is high. In the Alps it is common, even in the summer. Of 
leaves which become red in autumn there are two classes ; one set com- 
prises perennial leaves and those which, formed during the latter part 
* SB. k. Bohm. Gesell. Wiss., 1898, 10 pp. and 1 pi. 
f Quart. Journ. Micr. Sci , xlii. (1899) pp. 203-22 (1 pi.). Cf. this Journal, 
1897, p. 220. t Bot. Centralbl., lxxvii. (1899) pp. 81-7. 
§ Jahrb. f. wiss. Bot. (Pringsheim), xxxiii. (1899) pp. 171-231; Nature, lix. 
(1899) p. 296. 
