ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 559 



BOTANY. 



GENERAL, 

 Including the Anatomy and Physiology of Seed Plants. 



Cytology, 

 including- Cell-Contents. 



Cytology of Nectar-Glands of Vicia Faba.* — C. Stockard has 

 examined the nectar-glands on the stipules of Vicia Faba, and finds that 

 they contain rows of cells, the contents of which have different chemical 

 reactions, shown in life by different colours ; these are probably due 

 to differences in metabolic activity. The colour response resembles that 

 of litmus, acids turning the cell-contents red, and bases turning them 

 blue. When young the gland-cells differ but slightly from ordinary cells. 



The nuclei are granular, sometimes coarsely vacuolated, with one or 

 more plasmosomes surrounded by vacuoles ; they are spherical when 

 young, but later on are shrunken and irregular. They are generally 

 central, and probably give out material to the cytoplasm which ultimately 

 gives rise to granules. Rarely the nucleus loses its chromatin and takes 

 plasma stains. During secretion the cytoplasm first becomes vacuolar, 

 then slightly granular, and takes nuclear stains. These changes are con- 

 trolled by the nucleus which seems to be the centre of metabolic 

 activities, sharing in the formation of the secreted substance, but taking 

 no part in the actual process of secretion. 



Structure and Development. 

 "Vegetative. 



Investigations on the Anatomy of Allied Plants.f — A. Sarton 

 has tested the constancy of anatomical characters under varying condi- 

 tions of soil and climate. He calls attention to two kinds of species, 

 viz., Linnaean and Jordanian, which vary according to the different 

 values placed upon external morphological characters. The author 

 believes that where the anatomical differences of allied species are 

 experimentally interchangeable, such species should not be regarded as 

 distinct, however unlike may be their external appearance. On the 

 other hand, those whose anatomical differences are constant under 

 experiment are true species, though agreeing in their external appearance. 



The chief value of this investigation is in the evidence as to what 

 anatomical characters vary under given conditions. 



Physiology. 

 Nutrition and Growth. 



Chlorosis in Malvaceae.! — Baur has investigated the infectious 

 chlorosis of the Malvaceae, using for his experiments Abutilon striatum, 



* Bull. Torrey Bot. Club, xxxiii. (1906) pp. 247-62 (2 pis.), 

 t Ann. Sci. Nat. (Bot.), ser. 9, ii. (1905) pp. 1-117 (4 pis.). 

 % SB. Akad. Wiss., 1906, pp. 11-29. 



