ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 785 



Gummosis.* — Observations made by Dr. L. Savastano on Acacia arahica, 

 Phcenix dactylifera, Eucalyptus glohuhis, E. Sideroxylon, E. amygdalina, 

 E. Jiemijihloia, and Fraxinus Omus, confirm the conclusion previously arrived 

 at that this condition is comparatively rare in plants grown north of their 

 proper zone of cultivation ; and simihir observations on the Amygdalefe, 

 Aurantiaceas, vine, olive, Quercus, and Acer, show that any given species 

 subject to gummosis is more liable to it iu the southern than in the northern 

 portion of its zone of cultivation. 



Anaesthesia and Poisoning of Plants.f — Dr. F. Tassi records the results 

 of about 100 experiments on the elfect of a large number of anaesthetics 

 and poisons on different plants. Among the general conclusions at which 

 he has arrived is the existence of a j^roperty belonging to vegetable proto- 

 plasm analogous to that which in animals is called contractility, irritability, 

 &c. Of the substances which are fatal to animals, some are poisonous, others 

 anaesthetic, and others innocuous to plants. Among the latter are curare, 

 and the poison of the viper and cf the cobra. He observes also that the 

 state of inertia or rigidity of flowers is often accompanied by a change of 

 colour. 



Humboldtia laiirifolia as a myrmecophilous plant. J — Prof. F. 0. Bower 

 states that the ants enter this plant through an opening formed by rupture 

 of the superficial tissues, due apparently to pressure from within ; they thus 

 gain access to and hollow out the pith which had previously begun to 

 decay. They are probably supplied with food from the numerous glands 

 on the leaves. He could find no evidence that the symbiosis is of any 

 advantage to the plant. 



B. CRYPTOGAMIA. 



Symbiosis of a Bacterium and Alga.§ — Prof. A. Tomaschek records a 

 singular instance of symbiosis in a slimy growth found on the walls of a 

 greenhouse, which he found to consist of a Schizomycete in the zoogloea- 

 form agreeing most nearly with Bacillus megaterium. A dirty violet or 

 chocolate-brown colour was imparted to the mass by larger or smaller islands 

 of a green alga (chlorophyllous protophyte), Gloeocapsa polydermatica, im- 

 bedded in it. He regards the connection as an example, not of parasitism, 

 but of true commensalism brought about by the needs of the bacterium for 

 oxygen. 



Cryptogamia Vascularia. 



Rabenhorst's Cryptogamic Flora of Germany (Vascular Cryptogams). 

 — The most recently published parts of this work (Parts 8-10), by Dr. C. 

 Luerssen, complete the account of the Polypodiaceee, and comprise also 

 descriptions of the German species of Osmundacete, Ophioglossacese, and 

 EhizocarpeEe, and the commencement of a general description of Equi- 

 setaceae. Every species, as well as the more important varieties, are illus- 

 trated by beautiful woodcuts, the descriptions and the lists of localities are 

 very full, and nothing is omitted to make the work as full and accurate in 

 every particular as could be desired. 



Muscineae. 

 Leaves of Mosses. || — Sig. G. Arcangeli points out that a useful character 

 for discriminating species of moss can be drawn from the fact that in some 



* Nuov. Giorn. Bot. Ital., xix. (1887) pp. 101-3. t Ibid., pp. 29-101. 



X Eep. Brit. Assoc. Birmingham Meeting, 1886, p. 699. 

 § Oesterr. Bot. Zeitschr., xxxvii. (1887) pp. 190-2. 

 II Atti Sec. Tosc. Sci. Nat., v. (1887) pp. 241-3. 



