ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
617 
BOTANY. 
A. GENERAL, including the Anatomy and Physiology 
of the Phanerogamia. 
a. Anatomy. 
(1) Cell-structure and Protoplasm. 
Morphology and Physiology of the Cell.* — Dr. A. Zimmermann has 
investigated the structure of the chromatophores and differentiations of 
the cytoplasm in the vegetable cell, with the aid of the methods of 
fixing and staining employed by Altmann f in the case of animal cells. 
The following are his most important results. 
In various Commelynacese the leucoplasts were found to inclose 
small spherical bodies, apparently consisting of albuminoids, for which 
he proposes the term leucosomes. They were observed in the epidermal 
cells up to those of the youngest leaf, and were found to differ from those 
of the future assimilating tissue. Similar leucoplasts containing leuco- 
somes were also found in the mechanical cells, and in certain elements 
of the vascular bundles. They are distinguished by the fact that at no 
period of their existence do they contain starch, the formation of this sub- 
stance usually beginning in the immediately adjacent tissue. Those 
of the epiderm appear to be quite unable to form starch out of sugar 
transported to them. 
No destruction of the chromatophores takes place in those parts 
which exhibit etiolation from the want of iron ; but the chromatophores 
are usually considerably smaller and of lighter colour than the chloro- 
plasts of normally green leaves. They could only be detected with 
certainty by the use of very good objectives and of the best methods 
of staining. They also appear to be incapable of forming starch. 
Altmann’s stainable “ granules ” were found in the assimilating 
tissue, bodies consisting apparently of proteids, and very widely 
distributed. In Tradescantia albijiora it appears probable that they are 
connected with the nitrogenous nutrition. Except in young leaves of 
Polypodium ireoides , they had always a more or less spherical form. 
By the aid of the method of staining described in detail, the 
occurrence of protein-crystalloids was detected in the vegetative organs 
of many ferns. In Polypodium ireoides the crystalloids in the epiderm 
lie not in the cytoplasm, but in the cell-sap. In some ferns the author 
was able to follow the development of the crystalloids of the nucleus 
and found that they result from the coalescence of smaller granules or 
of vacuoles filled with albuminoids. Similar crystalloids were detected 
also in some flowering plants, e. g. Hippuris vulgaris and various 
Campanulacese and Scrophulariacem. They were found chiefly in the 
epiderm, and, except in Platycodon grandiflorum , always within the 
nucleus. In some cases they are subsequently absorbed, and their 
constituents probably used up again in metastasis. 
* Beitr. z. Morphol. u. .Physiol, d. Pflanzenzelle, Heft 1, 79 pp. and 2 pis. 
Tubingen, 1890. Cf. this Journal, 1888, p. 442. 
t Cf. this Journal, 1888, p. 146. 
