274 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



No. lviii., p. 427). — For all practical purposes of horticulture the experi- 

 mental method of sowing is no doubt the only one by which we should 

 care to know anything of the vitality of seeds, but this electrical method 

 is certainly one which appeals very strongly to the mind. This paper is 

 under the head of " Notes," and is abridged from the paper in Proc. Boy. 

 Soc. vol. lxviii. 1901, p. 79. Dr, Waller has been engaged in verifying 

 whether " blaze currents " may be utilised as a sign and measure of 

 vitality, but without limitation apparently to vegetable life. He has 

 selected as a test case the vitality of seeds, and has chosen the Bean 

 (Phascolus) for convenience. By "blaze current" (a new term) is meant 

 the galvanometrical token of an explosive change locally excited in living 

 matter, and if this " blaze current " is in the same direction as the 

 exciting current it is, in Dr. Waller's experience, proof positive that the 

 object under examination is alive. The magnitude of the " blaze " 

 reaction corresponds largely with the degree of vitality and to some extent 

 is a measure of it. A boiled Bean gives no " blaze current " in either 

 direction, and the comparison between the reactions of fresh seeds and 

 the same seeds killed by boiling is unmistakable and invariable. — B. I. L. 



Use of Water-excretion. 



Water-excretion, the Significance to Plants of Organs 

 effecting'. By Wladimir Lepeschkin (Mora, vol. xc. 1892, pp. 42-60). — 

 The function ascribed to these organs was that of preventing the injection 

 of the intercellular spaces with water by root pressure during closure of 

 the stomates, such injection being considered deleterious and inter- 

 fering with the free interchange of gases in plant assimilation. In the 

 author's first series of experiments he found that injection was rare, at 

 most partial, and did not increase beyond its first appearance, when the 

 water pores had been removed by cutting off the margin of the leaf, and 

 after the wound had healed by cork and the vessels (which bled at first) 

 closed by gum. In his second set of experiments he injected leaves 

 with water under the air-pump, and found that their power of carl ion 

 assimilation was unchanged, the increased permeability of the saturated 

 surface probably counterbalancing the diminution of the air surfaces 

 within. He concludes that hydathodes have rather an inherited than a 

 functional significance. — M. H. 



Generative Process of Zamia. 



Zamia, Spermatogenesis and Fecundation of ( U.S. Dep. . I 

 (Bur. PL Ind.), Bull. 2, pp. 7-92 ; pis. 7).— Mr. Herbert T. Webber 

 gives a very complete account of the development, shape, and fertilisation 

 phenomena in Zamia floridana, DC, and Z. immila> L. Pollen is 

 blown by the wind, enters between the scales, and is caught and drawn 

 into the pollen-chamber by a special mucilaginous fluid. There are two 

 small prothallial cells, or probably three, of which one is afterwards 

 "resorbed." The first prothallial cell protrudes into the second till the 

 latter appears to surround the former (cf. Conifcra). Bodies resembling 

 centrospheres (blcpharoj)ktsts) are formed in the cytoplasm. They are 

 at first very small, and a few radiating filaments converge to them. 



