ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
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Localisation of the Alkaloids in the Solanacese. * — M. P. Molle 
has investigated the distribution of the four alkaloids, atropine, hyos- 
cyamine, hyoscine, and nicotine in the various organs of the Solanacese. 
He finds them generally distributed through the aerial parts, but most 
concentrated in the youngest vegetative organs, especially in the epiderm 
and the vascular bundle-sheath ; they abound also in the root-cap. In 
the floral organs the largest quantity is contained in the carpels and 
ovules. In the mature seeds the alkaloids occur only in the integument, 
never in the embryo or endosperm. 
Distribution and Function of Carotin.| — Dr. H. Bitter Schrotter- 
Kristelli has found carotin in the aril of Afzelia Cuanzensis (Leguminosse) 
dissolved in a fatty oil, and not — as in all cases hitherto observed in 
flowering plants — in connection with the chromatophores. It has been 
described by Zopf as being in a similar way dissolved in a fatty oil in 
the rudimentary sporauges of a species of Mucorini. The author be- 
lieves carotin to be nearly related to the group of cholesterins, and to 
have a function connected with the respiration of the plant. For the 
group of the yellow pigments of plants and animals to which carotin 
belongs he proposes the name lipoxanthins. They occur in green leaves, 
autumn leaves, many flowers and fruits, arils, roots (carrot), in Euglena 
and the eye-spot of the swarm-spores of Ulvaceae, in lichens, bacteria, 
and Myxomycetes. These must be distinguished from another group of 
yellow pigments which are dissolved in the cell-sap, and are not con- 
nected with the chromatophores. A copious bibliography of the subject 
is appended. 
Classification of Mucilages.f — Instead of the usual primary classi- 
fication of mucilages into the two groups, cellulose-mucilages and true 
mucilages, M. L. Mangin proposes to distinguish them first of all into 
simple and mixed mucilages. The former are then classed under three 
heads — cellulose-mucilages, pectose-mucilages, and callose-mucilages, 
the characteristics of which are given in detail with respect to their 
physical, chemical, optical, and staining properties. Cellulose-mucilages 
are very rare, being almost confined to those derived from the roots of 
Orchidese, known as salep. Among pectose-mucilages are included those 
of the Malvaceae, Tiliaceae, Kosaceae, and Abietineae, and the mucilagin- 
ous sheath of certain algae, such as Zygnema, Gloeosporium, Nostoc, &c. 
Callose-mucilages occur in sieve-tubes, the membrane of the sporange of 
the Mucorini, &c., &c. Among mixed mucilages the only combination 
known to the author is that of cellulose and pectose-mucilages in varying 
proportions. They occur especially in seeds and pollen-grains, and are 
formed at the expense of cell-walls in contact with the air. Indeter- 
minate mucilages, which cannot be included under either of the above 
categories, also occur, such as that of the endosperm of the seed of the 
carob. 
Mucin in Plants. §— According to M. J. Ishii, the mucilages found 
in plants are not, as a rule, protein compounds, like those of animals, 
* Bull. Soc. Beige Microscopie, xxi. (1895) pp. 8-20. 
f Bot. Centralbl., lxi. (1895) pp. 33-46. 
X Bull. Soc. Bot. France, xli. (1894) Sess. Extraord., pp. xl.-ix. 
§ Bull. Agric. Coll. Imp. Tokyo, 1894, pp. 97-100. See Journ. Chem. Soc., 1895 
Abstr., p. 128. 
