550 SUMMARY OF CURRENT RESEARCHES RELATING TO 



hindered by the closing of the stomates from the reduction of the supply 

 of carbon dioxide. The coefficient of permeability of membranes is 

 usually, except for respiration at low temperatures, too low for the 

 exchange of gases to take place with its normal intensity ; hence the 

 need of stomates for aerial plants. 



Assimilation of Free Nitrogen by the Lower Organisms.* — In 

 pursuance of previous investigations on this subject, Herr B. Frank 

 claims to have determined experimentally that very low algal (or pro- 

 tophytal) forms of life, such as Oscillaria, Ulothrix, Pleurococcus, Cliloro- 

 coccuvi, and the protoneme of mosses, have the power of removing the 

 free nitrogen from the atmosphere and forming therefrom nitrogenous 

 compounds. This property he believes therefore to be common to all 

 vegetable organisms which contain chlorophyll, and that, in all pro- 

 bability, it is, like the assimilation of carbon, a function of their proto- 

 plasm. Whether the chlorophyll-pigment takes any part in the process 

 must remain at present undetermined. 



(4) Chemical Changes (including- Respiration and Fermentation). 



Respiration of the Fig-t — -D^- C. Lumia has examined the composi- 

 tion of the gas contained within the immature receptacle (fructification) 

 of Ficus carica, and finds it to consist of about 5-25 per cent. COg, 

 17 '9 per cent. 0, and 76-83 per cent. N. The proportion of carbon 

 dioxide is therefore about 130 times that present in the atmosphere, 

 showing that respiration must take place within the cavity of the fig 

 with extraordinary energy. 



Process of Oxidation in Living Cells.^ — Herr W. Pfeffer argues 

 against the existence of either ozone or hydrogen peroxide in the living 

 cell, on the ground that even the smallest quantities of the former 

 substance are fatal, while the latter rapidly colours the tissues a red- 

 brown in consequence of a process of oxidation, but without destroying 

 the activity of the protoplasm. There are, however, some tissues which 

 are not coloured in this way. Cells containing a soluble pigment are 

 bleached by the oxidation of the pigment. 



Oxalic Fermentation.§ — Herr W. Zopf finds in beer-wort-gelatine a 

 Schizomycete to which he gives the name SaccJiaromyces Mansenii, which 

 forms enilogenous spores, and which possesses the remarkable property 

 of producing oxalic acid instead of alcohol. This is the result of the 

 fermentation of carbohydrates belonging both to the grape-sugar and to 

 the cane-sugar group. 



y. General. 



Young State of Plants. || — Prof. K. Goebel contrasts the mature and 

 the young forms in a number of illustrations drawn from the higher 

 families of the vegetable kingdom, viz.: — Floridese (especially Lemanea 

 and Batracliospermum), Musci (especially Sphagnum, in which he finds 

 invariably a flat prothallium, whether the spores germinate in water 

 or not), Hepaticse, Pteridophyta, and Phauerogamia. As a general rule, 

 when the early differs from the mature form of a plant, it must be 



* Bel. Deutsch. Bot. Gesell., vii. (1889) pp. 84-42. Cf. this Journal, ante, p. 412. 

 t Nuov. Giorn. Bot. Ital., xxi. (1889) pp. 317-20. 



% Ber. Deutscli. Bot. Gcsell., vii. (1880) pp. 82-9. § T. c, pp. 94-7. 



II Flora, Ixxii. (1889) pp. 1-45 (2 pis. and 6 figs.). 



