ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 63: 



BOTANY. 



GENERAL, 



Including the Anatomy and Physiology of Seed Plants. 



Cytology, 

 including- Cell-Contents. 



Nature of Colour in Plants.* — H. Kraemer gives an account of 

 the behaviour of the colouring substances, extracted from very various 

 plant organs, towards chemical reagents. The plastid colours were 

 extracted by placing the fresh material in 05 p.c. alcohol, and allowing 

 it to macerate in the dark for a day or two. For complete separation 

 xylol and other solvents were subsequently used. The author gives a 

 list of the plants examined, indicating the part used, the nature of the 

 solvent, and the colour of the solution. He also gives a series of tables 

 indicating the colour changes produced in the solution by the addition 

 of various reagents, acid, alkaline and neutral. The pigment giving 

 the yellow colour in roots, flowers and fruits the author calls chromo- 

 phyl ; it is contained in a chromoplastid which varies much in shape, 

 and usually contains proteid substances. In the inner protected parts of 

 leaf-buds there is a yellow principle which the author calls etiophyl, and 

 which is contained in an organised body (etioplast), which does not 

 seem to contain either starch or proteid. The blue, purple and red 

 colour substances in flowers are dissolved in the cell-sap, and are usually 

 distinguished from the plastid colours by being insoluble in ether, xylol, 

 benzol, chloroform, carbon disulphide and similar solvents, but soluble 

 in water or alcohol. Similar cell-sap colour substances are found in 

 spring, and also in autumn, leaves. The author regards the chromo- 

 plastids of both flowers and fruits, as having the special function of 

 manufacturing or storing nitrogenous food-materials, for the use of the 

 developing embryo or seed, more especially as protein grains are usually 

 found in them. The same applies to the chromoplasts in roots, e.g. 

 carrot, where the proteids of the plastid are utilised by the plant of the 

 second year. The cell-sap colours, like other unorganised cell-contents, 

 such as alkaloids, volatile oils, etc., are regarded as incident to physio- 

 logical activity, and of secondary importance in the attraction of insects 

 for the fertilisation of the flower and dispersal of the seed. 



Structure and Development. 

 Vegetative. 



Arrangement of the Vascular Bundles in the Stem and Leaves 

 of some Dicotyledons.f — A. Col gives a detailed account of his work 

 on the course and arrangement of the vascular tissue in Dicotyledons.. 



* Proc. Amer. Phil. Soc., xliii. (1904) pp. 257-77. 



t Ann. Sci. Nat. (Botany), Ber. 8, xx. (1904) pp. 1-28S (40 tigs, in text). 



