October 7, 1915]. 



NATURE 



47 



torrents, and causes the hills to become smothered 

 in a mantle of their own debris, so that, as 

 .Stoliczka remarks, "it becomes almost an excep- 

 lion to observe a rock in situ," and the scenery 

 Incomes correspondingly tame. 



The occasion of the reading of Dr. de Filippi's 

 jjaper was memorable in more respects than one. 

 Xot only was an opportunity afforded, and hap- 

 pily utilised by the President of the Society, of 

 expressing the cordiality of our relations with 

 Italy, whether we are engaged together in peace- 

 lul exploration or in the more serious business of 

 \\ aq, but also by the participation in the discussion 

 t)l the father of Himalayan exploration in that 



observations of Dixon and Wigham^ at Dublin, 

 however, did not seem very promising : 100 seeds 

 of cress {Lcpidium sativum) were uniformly dis- 

 tributed over an even surface of moist quartz 

 sand, and after germination had taken place a 

 sealed tube containing 5 mgms. of radium bromide 

 was set I cm. above the central seed. The seed- 

 lings grew up, but without any curvature indicat- 

 ing positive or negative " radiotropism," and the 

 only noticeable effect was a slight depression of 

 growth in those within i cm. radius of the tube. 

 As stronger preparations of radium became avail- 

 able more definite retardations and inhibitions 

 were observed : thus Gager, in an elaborate 



KiL.. 2. —.Middle portion of Remo Glacier, Northern Branch, t'roin the Geographical /ournal, August. 



region. Col. God win- Austen, and of another 

 pioneer in Central Asian discovery. Sir F. Young- 

 husband. T. H. D. L. 



THE EFFECT OF RADIUM ON THE 



GROWTH OF PLANTS. 



\ MONG the many remarkable properties of 



'^*- radium it was perhaps natural to expect that 



it might have some definite effect on plants, and 



even, under suitable conditions, cause sufficient 



increase in the amount of growth to justify its 



use in horticulture and agriculture. The early 



NO. 2397, VOL. 96] 



report,^ noted a more or less complete inhibition 

 ; in cell activities in younger and especially em- 

 I bryonic tissues, with few exceptions. The action 

 ■ of radium through the soil, however, was different ; 

 ! germination and growth were both accelerated, 

 I and the plants furthest away were stimulated 

 i most. Acqua ^ found that different plants, and 

 } even different organs of the same plant, were 

 differently affected, the root system in general 

 responding more markedly than the aerial parts, 



1 Proc. Roy. Soc. Dublin, loo, 

 '■2 Mem. New York Bot. Card , 

 ^ Ann. Bt>/.(Romt], 19 



4, X., 178-192. 

 1908. 

 223-238. 



