498 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
pound poly -urates, in which atoms of hydrocarbons and fatty substances 
have taken the place of atoms of hydrogen. 
Crystalloids in the Cell-nucleus of Convolvulus.* — Prof. A. Borzi 
describes the occurrence of proteinaceous crystalloids in the nucleus of 
the cells of the parenchyme of the leaves and cotyledons of several 
species of Convolvulus. They occur singly or in masses, have often a 
rod-shaped form, and are separated from the rest of the nuclear proto- 
plasm by a very thin protoplasmic envelope. They are found in the 
young cells, and the author believes them to be formed at the expense of 
the substance of the nucleus, as the result of a process of degeneration. 
They can be well shown by staining with Bohmer’s haematoxylin after 
fixing by Kleinenberg’s fluid ; but the best reagent is a 10 percent, solu- 
tion of gold chloride, which stains the crystalloids an intense reddish- 
brown colour, the rest of the cell-contents a dark ultramarine. 
Alkaloids of the Orchidaceae.t — M. E. De Wildeman finds in Den- 
drobium nobile and other species of the genus, crystalloids similar to 
those previously found in Epiphyllum, which he states to be insoluble 
in alcohol. The reactions of the crystalloids contained in D. nobile 
are given in -detail, and their presence is affirmed in the aerial roots, 
in the stem, in the parenchyme of the leaves, in the petals, and in the 
ovary. They occur in especial abundance in the cells which are in a 
state of active division, in the epiderm, and in the hairs ; they are also 
found in some of the cells which contain raphides. In D. Ainsworthii 
the author found them also in the leaves and in the petals. 
Crystalline Deposits in the Leaves of Anonaceae and Violaceae.t— 
Prof. J. Borodin has examined the leaves of 340 species belonging to 
38 genera of Anonaceae, and those of 164 species belonging to 17 
genera of Violaceae, for the purpose of determining the constancy of 
the presence of crystals of calcium oxalate as a character for classifica- 
tion. 
In the Anonaceae he finds the presence of unicellular oil-glands 
— almost always in the spongy parenchyme — to be a constant character. 
This is characteristic also of the Magnoliaceae, but not of the Ranun- 
culaceae. Crystals of calcium oxalate were found in 92 per cent, of the 
species examined, occurring either in the mesophyll, along the veins, 
or in the epiderm ; the first of these positions is very inconstant, the 
second very rare, the third almost universal. In the occurrence of 
crystals in the epiderm, the Anonaceae again agree with the Magno- 
liaceae, and differ from the Ranunculaceae. The author describes six 
distinct types founded on the form and distribution of the crystals, 
characteristic in most cases of the genera. 
In the Yiolaceae both clusters and single clino-rhombic crystals 
occur in the leaves, and may be classified under eight types, according 
to their arrangement and distribution. These also correspond with 
the division into genera, though not so universally as in the Anonaceae. 
* Bull. Soc. Bot. Ital., i. (1892) p. 45. 
f Bull. Soc. Beige Microsc., xviii. (1892) pp. 101-12 (1 fig.). Cf. this 
Journal, 1887, p. 983. 
X Arb. St. Petersb. Naturf.-Gesell. (Bot.), 1891, pp. 177-205. See Bot. Centralbl., 
1. (1892) p. 51. 
