1020 SUMMARY OF CURRENT RESEARCHES RELATING TO 



threefold the aetivity of diastase. The presence of cane- sugar in the 

 sap has but little effect on the action of invertin, while, if any 

 considerable amount of invert-sugar is already present, it is consider- 

 ably retarded. 



Vines's Vegetable Physiology.* — "We have liere for the first time 

 an original handbook of Vegttable Physiology in the English 

 language, brought down fairly to the present state of our knowledge. 

 Dr. Vines has enlarged the notes of his own lectures at Cambridge, 

 and treats tlio various divisions of the subject in the following 

 sequence : — Structure and Properties of the Plant-cell (2 lectures), 

 Absorption ('2), Movement of Water in Plants (1), Transpiration (1), 

 Food of Plants (1), Metabolism (5), Growth (1), Irritability (6), 

 Reproduction (2). While the results obtained by other observers 

 up to the time of writing are not neglected, the author gives his 

 own views on all the debatable points which arise in the course of his 

 lectures, frequently supported by independent observations of his own. 

 It is the most important original botanical work which has appeared 

 for some years from the English press. 



B. CRYPTO GAMIA. 



Cryptogamia Vascularia. 



Dehiscence of the Sporangium of Ferns, f — Herr K. Prantl 

 repeats his former statement that the cells of the annulus of the 

 sporangium contain bubbles of air inclosed in a continuous layer of 

 protoplasm which lines the cell-walls, especially the inner ones. 

 This air is absorbed by water which enters the protoplasm through 

 the cell- wall by virtue of osmose, and is again suddenly expelled 

 when the water is withdrawn, causing the rupture of the cell. 



Rods in the Intercellular Passages of the Marattiacese.j — 

 Herr H. Schenck has examined these bodies, already described by 

 Luerssen, in several species of Maratlia and Angiopteris. He does 

 not regard them, as Luerssen does, as cuticular thickenings, but finds 

 them to consist of a substance of doubtful chemical composition 

 which is deposited between the cellulnse-membrane and the thin 

 cuticularized membrane which clothes the intercellular spaces. They 

 sometimes attain a filiform condition, and are probably organs for the 

 purpose of secretion. 



E.hizocarpese.§ — The portion of Mr. J. G. Baker's Synopsis of 

 the Khizocarpcae already published comprises monographs of the 

 genera Salvinia, Azolla, and Marsilea. Of Salvinia he describes 

 thirteen species, of which three are new. They are arranged in four 

 groups, distinguished by the structure of the frond. Of the five 



* Vines, S. H., ' Lectures on the Physiology of Plants,' 709 pp. and 76 figs. 

 8vo, Cambridge, 18S6. 



t Ber. Deutsch. But. Gesell., iv. (1886) pp. 42-51. See this Journal, v. (18S5) 

 p. 276. 

 • J Ber. Deutsch. Bot. Gesell., iv. (1886) pp. 86-92 (1 pi.). 



§ Journ. of Bot., xxiv. (1886) pp. 97-101, 274-83. 



