143 
THE EFFECT OF CENTRIFUGAL FORCE ON PLANTS. 
F. M. Anprews, Indiana University. 
The first experiments made on plants with centrifugal force were per- 
formed by Knight* in the year 1806. His apparatus was simply arranged, 
was run by water power and the amount of centrifugal force that his 
machine produced was very small. His object was to observe the behavior 
of seedlings under a somewhat intensified gravitational force. Since the 
time of Knight some other investigators have investigated the action of 
centrifugal force on various plants and especially some of the studies 
have been made on seedlings. These are generally of such size or can be 
so selected, as to lend themselves advantageously to experimentation of this 
sort. Among the investigators who followed Knight in this field of study 
may be mentioned Miiller’? who made a study of the growth processes of 
roots when acted on by centrifugal force. As in the case of Knight the 
amount of centrifugal force which Miiller employed in his experiments also 
was small. Ten years later the subject was again prominently investigated 
in a similar way by Elfing? who also used only a small amount of cen- 
trifugal force. The amount of such force which Elfing used varied from 
29-50g, which was slightly greater, however, than that employed by the 
above mentioned investigators. The original paper of Elfing I have not 
seen. An extract of its contents has been given by F. Schwartz in the 
Botanische Zeitung Bd. 39, 1881, P. 176 above referred to. At the same 
time that the paper of Elfing appeared a similar piece of investigation had 
been completed independently by I*. Schwartz.“ This paper by Schwartz 
_also appeared in 1881 from Pfeffer’s laboratory in Tiibingen. Schwartz 
worked with a specially constructed form of centrifugal machine which, 
however, did not use the ordinary form of reyolying drum. Instead it was 
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- 
mens 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 and which I. can 
not discuss here but will refer to them at a later period. Schwartz used 
control plants and the number of gravities employed by him was also small 
and did not exceed 30 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 experi- 
ments performed by them does not apply in the preceding statements since 
Knight, T. A. Horticultural Papers P. 124. 
*Miiller, N. J. C. Die Wachsthumerscheinungen des Wurzel. Botanische Zeitung, 
Bd. 29, 1881, P. 716. 
®Hlfing, Fred., Beitriige zur Kenntniss des Physiologischen Einwerkung der 
Schwerkraft auf die Pflanzen, Botanische Zeitung, Bd. 39, 1881, P. 176. 
aaa eee F., Untersuchungen aus dem Botanischen Institut zu Tiibingen Bd. 1, 
