143 



THE EFFECT OF ( 'E.NTUIFrciAL F(»K('E (»\ I'LAXTS. 



F. ]\r. Andukws. Iiidiiina T'nivorsity. 



'I'lic tii-sI cxiicriiiicnts iii.ulc on iihiiits with ooiitrifusal force wcrr per- 

 formed liy Kiiiiilit' ill tlic ycai' isoc. His appariitn.s was simply arrariKed, 

 was run by water power and (lie amount of coiitrifuf^al force tiiat his 

 maciuiie i>roduce([ was vt-ry small. His object was to observe the behavior 

 of seedliiij^s under a somewhat intensified gravitational force. Since the 

 time of Knijibt some otlu>r investisjiitors liave investigated the action of 

 centrifugal force on various i)lanls and especially some of the stmlics 

 have been made on s(>edlings. These ai'c generally of such size or can be 

 so selecte(l, as to lend tliemselves advantageously to exi)erimentation of this 

 s(U-t. Among the investigators who followed Knight in this Held of study 

 may be mentioned :Miiller- who made a study of tlie growth processes of 

 roots when acted on by centrifugal force. As in the case of Knight the 

 anH)unt of centrifugal force which Midler employed in his experiments also 

 was small. Ten years later the sul)ject was again prominently investigated 

 in a sinular way by EUing-' who also used only a small amount of cen- 

 trifugal force. The amount of such force which Elfing used varied from 

 U9-50g. which was slightly greater, however, than that employed by the 

 above mentioned investigators. The original paixn- of Elfing I have not 

 seen. An extract of its contents has been given by F. Schwartz in the 

 liotanische Zeitung Bd. 39, ISSl, P. 17() above referred to. At the sanje 

 time that the paper of Elfing appeared a similar piece of investigation had 

 been completed independently by F. Schwartz.^ This paper by Schwartz 

 also apiH'ared in ISSl from Pfeffer's laboratm-y in Tubingen. Schwartz 

 worked wdth a specially constructed form of centrifugal machine which, 

 however, did not nse the ordinary form of revolving drum. Instead it wa.s 

 so constructed that it carried at right angles to the revolving main shaft, 

 a second shaft that carried a number of boxes which contained the speci- 

 meps to be investigated. These seedlings were grown in sawdust which, 

 however, is objectionable in some respects to use in a machine of this type 

 during experimentation. The boxes just referred to were so placed on the 

 second shaft as to balance one another during centrifuging. Various other 

 contrivances in connection with this machine were used iin<l which I can 

 not discuss here but will refer to them at a later i)eriod. Schwartz used 

 control plants and the nundier of gravities employed by him was also small 

 and did not exceed .'tU gravities in any of his experiments. He as well as 

 the other investigators did not observe a retardation of the growth of the 

 seedlings used in their experiments. The use of the klinostat as used by 

 Sachs or as originally constructed and used by Hunter and others in exiieri- 

 ments performed by them does not apply in the preceding statements since 



^Knight, T. A. Horticultural Papers P. 124. 



-Miiller. IS'. .T. C. Die Wachsthumerscheiuunjjon rtes Wurzel. Botanisehe Zeitung. 

 B(l. 29, ISSl. P. 716. 



"Elfinfr. Fri'd.. Bcitriifro zur Kfiintniss dcs Physiolosischen Binwerkung der 

 Schwerkraft auf die Pflanzen. Botanisehe Zeitnnjj. Bd. 30. 1881, P. 176. 



^Schwartz, F., Untcrsuchungen ans dcni Botanischcn Institut zu Tiibingon Bd. 1, 

 1SS1-1S25 



