ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 185 



Chemical Changres. 



Action of Water on Aleurone Grains.* — H. Joffrin, as a result 

 of various experiments, concludes that the modification of aleurone 

 grains iu the white lupin is the result of the absorption of a fixed, 

 optimum quantity of water, the process being- hindered by diminution 

 or excess of this quantity, which appears to be equal to the dry weight 

 of seed acted upon. The rapidity of transformation proves that the 

 reaction is of a chemical nature, not diastasic. The author puts forward 

 the hypothesis that the cells contain mineral substances which are 

 brought into solutions of a definite strength, and these are capable of 

 acting upon the aleurone grains. 



Leaf Coloration.f — A. Gautier, in connection with a recent paper 

 published by M. Mirande, draws attention to his former work upon 

 leaf-coloration produced by artificial means, e.g. wounding, and also 

 that which takes place normally in autumn. He has proved that 

 the red colouring matter is neither azotic nor phosphoric in nature, 

 and therefore cannot be a degradation product of chlorophyll. In 

 the vine the colouring matter is formed from acid-phenols, and is of 

 the nature of a tannin. It differs somewhat in the grape-ivy. The 

 author believes that the various shades of red in autumnal leaves are due 

 to the oxidation of a chromogen produced in the leaves ; also that the 

 various pigments vary with each species of plant, just as do the colours 

 of fruits. 



Plant Mutation.! — The late H. M. Slade began an interesting 

 series of investigations upon the action of alkaloids on metabolic 

 processes. His experiments show that the alkaloid characteristic of 

 a family aids the diastatic activity of the members of that family, and 

 this favouring action appears to run parallel with the natural relation 

 of the family. Alkaloids of distant families retard diastatic action. 

 Variable families appear to be hindered by alkaloids in this respect. 

 These facts were used successfully in promoting the germination of the 

 seeds of S'chizanthus, Tomato, Digitalis, etc. On the contrary, the 

 alkaloids which favoured diastatic reaction hindered the oxidase. Since 

 alkaloids aid oxidation, they probably increase the oxidising capacity of 

 the plant-cell, where the latter lacks oxidases. 



General. 



Variation in Ophrys aranifera§. — E. U. Kalkhoflf has discovered 

 two remarkable instances of malformation in the flowers of Ophrys 

 aranifera. The first specimen had two flowers of normal size and 

 colour, but the lip was absent, and the column was modified. In the 

 lower flower the rostrum also varied, while the stamens and pollen 

 were absent. The second specimen, growing in another district, had 

 four flowers, in three of which the column and stamens were normal, 



* Rev. Gdn. Bot., xviii. (1906) pp. 327-31 (figs. 1-4). 



t Comptes Reudus, cxliii. (1906) pp. 490-1. 



: Amer. Journ. Pharm., 1906, pp. 811-17. 



§ Verb. Zool.-Bot. Gesell., Ixi. (1906) pp. 434-6 (1 pi. and 2 figs.). 



