NOTES AND ABSTRACTS. 



241 



found (the first grows at over 12,000 feet in Tibet, and the second on 

 the warm and humid slopes of the Himalayas). 



The peculiar nodosities or swellings on the roots of Elaeagnaceae 

 are apparently distinctly of service to the plant; the author's experi- 

 ments showed that plants inoculated with extract of other tiodosities 

 were much more vigorous than those which were not so treated. 



The pollen of Hippophae is carried by ants, which visit aphides on 

 the plant, but also and especially by the wind. Elaeagnus, which forms 

 flowers in winter and even when covered by snow, is able to pollinate 

 itself, but is usually fertilized by insects. 



The fleshy fruit of Hippophae is relished by birds, but the author 

 found that all the seeds were destroyed in the gizzard of the " geai " 

 (? jay or jackdaw) which was kept by him, and he doubts the import- 

 ance of this method of distribution, although he admits that the 

 presence of Hippophae in many isolated places (as on the railway 

 talus at Perrignier) is best explained by bird-distribution. Usually the 

 fruit dries on the tree during winter and falls off in spring. (The pulp 

 hinders or prevents germination.) The fruit is able to float for long 

 distances in consequence of the air being retained between the seed 

 and the membranous sac formed by the ovary. 



Variegation in Elaeagnus is considered as caused by disease. 



There is a discussion of the affinities of the family and some interest- 

 ing remarks on the physiological part played by calcium oxalate, 

 tannin, and eleagnine in the economy of the plant. 



Most of the book is taken up with the comparative anatomy of 

 roots, stems, and leaves, but including the primary and secondary struc- 

 tures, growing points, development of flower, pollen-sac, embryo-sac, 

 fertilization, development of embryo; in fact, every part is described 

 microscopically and illustrated by excellent figures. 



The classification adopted is that of Van Tieghem and Bonnier. It 

 is impossible to abstract these details. One should, however, mention 

 that complete keys are furnished by which one can discover the species 

 of Elaeagnus or Shepherdia merely by the anatomy of the stem, or of 

 the leaf or of the root. Perhaps the most interesting part of this 

 section is the clear description of the development of the characteristic 

 stellate hairs of the order and of the fruit of Hippophae. — G. F. S.-E. 



Electricity and Micro-Orgranisms. By G. E. Stone {Bot. Gaz. 

 xlviii.; Nov. 1909; pp. 359-379; 2 figs.).— In order to test the 

 influence of electric currents on the growth of bacteria, the author used 

 wide-mouthed jars (21 cm. by 10 cm.) stoppered with cotton-wool and 

 containing strips of copper and zinc (4 cm. wide). These electrodes 

 were placed in the jars against the side and connected by copper wire. 

 Under the influence of the current so produced (0*1 milHampere) the 



I number of bacteria per cubic centimetre increased from about 3000 to 

 43,000 on the flrst day and 108,000 on the second day. In similar 

 jars not stimulated the number was only 3463 on the first and 



I 3435 per c.cm. on the second day. 



VOL. XXXVI. -D 



