476 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
(2) Other Cell-contents (including- Secretions'). 
Chlorophyll ill the Embryo.* — Mr. C. B. Atwell states that chloro- 
phyll occurs in the embryo of Tilia americana and Ipomoea purpurea. 
In the latter species the chlorophyll appears as soon as the first traces 
of the cotyledons can be recognized in the cross-sections of the seed. 
It is abundant in the pod while the seeds are developing. 
Colouring Matter of the Buds of the Horse-chestnut.f— Prof. L. 
Macchiati finds this to be an uncrystallizable substance resembling the 
phycoerythrin of Kutzing and Cohn, but differing from that substance 
in being unaffected by light. It is soluble in water, but insoluble in 
alcohol, benzin, chloroform, ether, and other solvents. When dissolved 
out by boiling water and evaporated, it has a dark cherry-red colour. 
Colouring Matters in the Integument of Seeds.:}: — M. L. Claudel 
states that the researches of M. Poisson have established that the seat 
of the colouring matter in the integument of the seed is very variable. 
It is nearly always a protecting layer in the integument, the walls of 
which become thickened, and often coloured. The author now describes 
the following variations : — 
In Cruciferse it is the third layer which becomes the protecting layer, 
■while it is the fourth in Cistus , and the fifth in Tilia. In Phlox Drum- 
mondii, Gentiana germanica , and Scabiosa arvensis , it is the superficial 
tissue that becomes coloured. Finally, it may be said that sperm odermic 
colouring matters are formed only in living cells. There are a certain 
number of seeds in which the localization of colouring matter does not 
take place in the protecting layer (e. g. Acanthus mollis). 
Colouring Matter of Grapes.§ — M. E. Laurent finds in fruits two 
distinct layers of colouring substances, one of which depends absolutely 
on light for its production, while the other does not. The composition 
of the red colouring matter of grapes corresponds nearly to the formula 
C 2 H.,0. It may be derived from glucoses by a process of dehydratization 
which takes place in the fruit during the last period of its ripening. 
Calcium-salts and Silica. || — In a very important and exhaustive 
work, Dr. F. G. Kohl treats of the mode of occurrence of these sub- 
stances in vegetable cells and tissues, and of their physiological 
significance. 
Calcium oxalate occurs in five different forms — as monoclinic and 
quadratic crystals, as concretions (Driisen), as spkmrites, as raphides, 
and as crystalline sand. By a long series of experiments he arrived at 
conclusions (which our space prevents us from going into) of the con- 
ditions under which these various forms are assumed. The lime may, 
under certain conditions, become again separated from the oxalic acid 
and act as a carrier of carbohydrates ; while the excreted calcium oxalate 
plays a not unimportant part in the mechanical strengthening of the 
tissues. 
* Bot. Gazette, xv. (1890) p. 46. 
f Nuov. Giorn. Bot. Ital., xxii. (1890) pp. 76-8. 
X Comptes Rendus, cx. (1890) pp. 298-300. Cf. this Journal, ante, p. 196. 
§ OR. Soc. R. Bot. Belg., xxix. (1890) pp. 71-6. 
ii ‘ Anat.-phys. Unters. d. Kalksalze u. Kieselsaure in d. Pflanze,’ Marburg, 
1889, xii. and 314 pp. and 8 pis. See Bot. Centralbl., xli. (1890) p. 69. 
