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SUMMARY OF CURRENT RESEARCHES RELATING TO 
BOTANY. 
A. GENERAL, including the Anatomy and Physiology 
of the Phanerogamia. 
a. Anatomy. 
(1) Cell-structure and Protoplasm. 
Oligodynamic Phenomena of Living Cells.* — Under this name the 
late Prof. C. v. Nageli describes some very remarkable properties of 
living cells in their behaviour towards excessively small quantities of 
metallic substances in solution. The observations were made chiefly on 
Spirogyra nitida and dubia. If in water which is previously “ neutral ” 
i. e. not pathogenic to Spirogyra — a gold coin containing 10 per cent, 
of copper is placed, the water acquires the oligodynamic property of 
killing the Spirogyra in a very few minutes. The poison acts very 
much more energetically in the presence of only one or two filaments 
than if a larger quantity of the alga is present in the water. In this 
way 1 part of copper in 1000 million parts of water may be pathogenic. 
Glass vessels in which a piece of the poisonous metal had previously been 
placed acted in the same manner. In this way distilled water is often 
poisonous to Spirogyra. On the other hand, the presence in the water 
of certain insoluble solid substances, such as sulphur, carbon, wood, 
linen, cotton, gum, &c., and a large quantity of the alga itself, diminish 
its poisonous properties. 
Oligodynamic poisoning manifests itself in the living cell in a dif- 
ferent way from chemical poisoning. In the former case the protoplasm 
remains adherent to the wall of the cell, while the spiral band of chloro- 
phyll detaches itself, and becomes looped into a solid mass surrounding 
the cell-nucleus; the substance of the band swells up, and presents, 
on transverse section, a cylindrical or oval form. The oligodynamic 
poisoning may begin to manifest itself in a period as short as from three 
to six minutes. 
Prof. C. Cramer f has repeated the experiments of Prof. Nageli, and 
has confirmed the more important results obtained by him. 
Cell-nucleus of Spirogyra.J — Using Flemming’s chromo-aceto-osmic 
fluid as a fixing reagent, M. C. Decagny states that in Spirogyra seti- 
formis the nucleole produces a substance which it expels, sometimes 
through openings, sometimes by a complete rupture, the result being to 
bring into contact with the nuclear fluid a substance which immediately 
coagulates and takes a definite form. The nucleolar substances are, in 
Spirogyra , differentiated in the form of a large central body which, 
instead of disappearing, as in other nuclei, at the moment of division, 
persists after division has taken place. These substances bring about 
the reconstitution of the two halves of the nucleus by the assistance of 
a directing force located within the primitive nucleus. 
* Denkschr. Schweiz. Naturf. Gesell., xxxiii. (1893) 43 pp, f Tom. cit., 8 pp. 
X Comptes Kendus, cxvi. (1893) pp. 269-72, 535-7. Cf. this Journal, 1891, 
p. 360. 
