638 SUMMARY OF CURRENT RESEARCHES RELATING TO 



the author concludes thai nuclei vary in richness of chromatin, and that 

 it is only possible to distinguish chromatin from linin where the nucleus 

 is relatively poor in chromatin. Moreover, in all cases investigated during 

 the present work, the author finds that the spirem stage is clearly tin- 

 result of fusion of paired threads. 



Starch-grains and Oil-drops in Conifer- wood.* — G. Lakon con- 

 fcributes a paper upon his discovery of starch-grains and drops of oil in 

 the pitted tracheites of young secondary wood of Conifers. The author 

 lias tested his results in various experiments, and is led to the conclusion 

 that both the starch and the oil are the products of the mutual reaction 

 of the glycose and of certain plasmatic remains present in the tracheides. 

 It is pointed out that only two other such instances are recorded, i.e. in 

 Milium and Plantaf/o major • the first is a moss and scarcely forms a 

 parallel case ; in Plantago protoplasmic remains w r ere found, but this is 

 less remarkable since this genus is herbaceous. Without venturing any 

 opinion as to the reason of such a condition, the author draws attention 

 to the fact that the plasmatic contents of the tracheides are the last to 

 disappear, and remarks that in these sheltered cavities the tenacious 

 protoplasm can live and carry on its functions for a longer time than 

 elsewhere. 



Peroxydase and Respiratory Pigments.! — W. Palladine and P. 

 Iraklionoff have made numerous experiments dealing with the nature of 

 peroxydase and its relation to the respiratory pigments. The results 

 show that the quantitative distribution of peroxydase is in proportion to 

 that of the chromogenic respiratory pigments ; peroxydase occurs as a 

 free or fixed diastase in different plants, and the quantity present varies 

 very much. It is probable that yeast can cause alcoholic fermentation 

 even in the presence of air, owing to its entire or partial freedom from 

 oxidizing diastases. Albuminoids prevent the liberation and purification 

 of peroxydase. The methods of proving the presence of respiratory 

 pigments vary with the specific peculiarities of each plant, the same 

 reagent acting differently in this respect in different plants ; thus, a 

 reagent which accelerates the formation of pigment in wheat-embryos, 

 prevents it in etiolated stems of Vicia Faba. Heating to boiling-point 

 aqueous extracts containing respiratory chromogenes, causes chemical 

 changes which render the formation of the pigments impossible, and it 

 probably destroys the substances required by the peroxydase for the 

 formation of the respiratory pigments. 



Structure and Development. 

 Vegetative. 



Evolution of Conducting-tissues of Vascular Plants.t.— G. Chau- 

 veaud pul dishes the results of twenty years' work in connexion with the 

 conducting tissues of vascular plants. This publication comprises three 

 parts, viz. : 1. An historic review dealing with the vascular system and 



* Ber. Deutsch. Bot. Gesell., xxix. (1911) pp. 175-8 (1 fig.). 



t Rev. Gen. Bot., xxiii. (1911) pp. 225-47. 



t Ann. Sci. Nat. (Bot.) ser. 9, xiii. (1911) pp. 113-439 (218 figs.). 



