996 SUMMARY OF CUKflENT RESEARCHES RELATING TO 



drops of a 1 per cent, solution of litiiium chlorate, and then determining, 

 by means of the spectroscope, the extent to which the lithium was absorbed. 

 The general results obtained were that water is absorbed so slowly and in 

 such small quantities through these organs in comparison to the root, that 

 it is without physiological value to the plant. This applies both to the 

 ordinary leaves and to those parts which are designated by Lundstrom 

 as specially constructed organs for the absorption of water. 



Bleeding'.* — Herr C. Kraus has examined the phenomena of " bleed- 

 ing " in a number of species, both woody and herbaceous. He finds it to be 

 invariably the case that when the plant is still attached to the soil by its 

 root, the sap that first exudes from the wound is acid, while that which 

 flows out later is either neutral or slightly alkaline ; and the same is the 

 case with cut shoots of the vine. The exuding sap is derived partly from 

 the vessels and tracheids of the wood, partly from the tissue immediately 

 adjacent to the wound. A larger amount of bleeding takes place, as a 

 rule, from younger than from older shoots. 



Sachs's Vegetable Physiology.f — This most important work, an enlarge- 

 ment of a portion of Prof. J. von Sachs's ' Test-book of Botany,' is divided 

 into six sections, viz. : — (1) Organography ; (2) The External conditions 

 of Vegetable life; (3) Nutrition; (4) Growth; (5) Irritability; (6) 

 Eeproduction. Under the head of Organography all the organs of a plant 

 are classified under five heads, viz. : — (1) Koot ; (2) Shoot (including 

 leaves) ; (3) Sporangia and Spores ; (4) Archegonia ; (5) Antheridia. 

 In the section on Nutrition, a very large space is devoted to the phenomena 

 connected with the absorption of water and the passage of nutritive 

 material from one part of the plant to another ; and the author adheres to 

 his previous view that the transfer is effected through the lignified tissues. 



B. CRYPTOGAMIA. 



Symbiosis of a Bacterium and Alga4 — Dr. M. Kronfeld objects to 

 Tomaschek's description of the association observed between a Bacillus 

 and a Gloeocajpsa as " symbiosis," § on the ground that it is not shown 

 that the latter can derive any possible benefit from the former. He 

 considers it more probable that the so-called bacillus is really the product 

 of the breaking up of the filaments of an alga, a similar phenomenon having 

 already been described by Zukal in the case of Drilosiphon.\\ 



Cryptogamia Vascularia. 



Apospory.lT — Prof. F. O. Bower repeats in detail the phenomena con- 

 nected with the aposporic reproduction already described by Drewry and 

 himself in the ferns Atliyrium Filix-femina var. clarissimum, and var. 

 plumosum elegans, and in PolijsticJium angulare var. pulcherrimum. He 

 points out that sporal arrest may occur, irrespective of the presence or 

 absence of these substitutionary vegetable growths which so often accompany 

 it. In the first and last varieties mentioned above the arrest in the develop- 

 ment of the spores is, in the majority of cases, complete, not advancing 



* Forsch. a, d. Geb. d. Agricultur-physik, x. (1887) pp. 67-144. See Bot. Centralbl., 

 xxxi. (1887) p. 137. 



t Sachs, J. v., 'Lectures on the Physiology of Plants,' translated by H. Marshall 

 Ward, 836 pp. and 455 figs., Oxford, Clarendon Press, 1887. 



t Bot. Centralbl., xxxi. (1887) pp. 350-2. 



§ See this Journal, ante, p. 785. |1 Ibid., 1884, p. 601. 



^ Trans. Linn. Soc. Lond.— Bot., ii. (1887) pp. 301-26 (3 pis.). See this Journal, 

 1885, pp. 99, 491 ; ante. p. 622. 



