ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
619 
a substance, i. e. an action on certain pigments similar to that produced 
by alkalies, is by no means a certain proof that the substance in question 
contains an alkali, or even possesses basic properties. 
(2) Other Cell-contents (including Secretions). 
New Green Vegetable Colouring Matter.* — Mr. C. M. Smith 
describes a green colouring matter obtained from the green bitter pulp 
of the fruit of Triciiosanthes palnmta. The spectrum of its alcoholic 
solution differs from that of chlorophyll in its first absorption-band 
having its centre almost midway between the two chief chlorophyll- 
bands, while the bands III., IV., and V. are probably coincident with 
bands of true chlorophyll. Its behaviour with ammonium sulphide 
entirely differs from that of chlorophyll. This colouring matter 
appears to be a substance in which the “ blue chlorophyll ” of Sorby 
or the “green chlorophyll” of Stokes is replaced by some other 
substance easily decomposed by reducing agents and acids. 
Chromatophores of Bleached Leaves.^ — Dr. A. Zimmermann finds 
well-defined chromatophores to be generally present in albinized parts of 
plants ; they agree with the normal green chloroplasts in form, but are 
much smaller and of a much lighter colour. Frequently also they 
are of a vesicular character, from containing one or more vacuoles. 
But all these modified chromatophores, even the vesicular ones, still 
retain the power of forming starch, though to a diminished extent. 
Proteinaceous bodies in Oncidium. } — Herr K. Mikosch finds in the 
cells belonging to the epiderm of both sides of the leaf of Oncidium 
microchilum , from Guatemala, peculiar proteinaceous bodies formed out 
of the granular protoplasm of the cells, and bearing a strong resemblance 
to those previously found by Molisch § in Epiphyllum. They are annular, 
fusiform, or loop-shaped, partially or entirely soluble in alcohol, and 
are coloured bright red by Millon’s reagent, pink by a solution of sugar 
and sulphuric acid. Their occurrence is exceedingly irregular, and nothing 
could be determined as to their function ; they appear to be formed 
independently of external conditions, sometimes disappearing, and being 
apparently again re formed. No similar structures were found in other 
species of Oncidium examined. 
Tannin and its Functions. || — Dr. K. Bauer describes in detail the 
mode of occurrence of tannin in the following plants, chiefly in the 
leaves, stem, root, and rhizome : — Iris pseudacorus , I. sibirica , Marica 
NoriJiiana, Ficus elastica, F. australis , Cyperus Papyrus , Saururus cernuus. 
It may occur either in the ordinary cells of the tissue or in specially 
formed cells, idioblasts. In the former case it is often accompanied by 
starch or chlorophyll ; in the latter case it is always the sole content of 
the cell. 
As to the function of the tannin, it is clear that in many cases, 
* Proc. Roy. Soc. Edinburgh, March 17, 1890. See Nature, xli. (1890) p. 573. 
f Ber. Deutsch. Bot. Gesell., viii. (1890) pp. 95-7. 
x T. c., pp. 33-8 (1 pi.). § Cf. this Journal, 1886, p. 89. 
|| Oesterr. Bot. Zeitschr., xl. (1890) pp. 53 -7, 118-23, 160-3, 188-91. Cf. this 
Journal, ante , p. 53. 
