138 



The results were as shown in Table IV. 

 Table IV. 



Thus with centrifugai forces considerably greater than those 

 given by the Piccard method the hypocotyls curved, as was expected, 

 inwards, i. e., towards the centre, except in Exp. 25. It must be 

 especially noted that this experiment was unsatisfactory, the coty- 

 ledon having been insecurely fixed. 



Though the experiments are not sufficiently numerous it must 

 be aliowed that a comparison of Tables IV and III shows that the 

 results obtained by the Piccard method cannot be due to physical 

 bending away from the centre. 



We must therefore conclude that the cotyledon is geo-perceptive, 

 and that, if any similar sensitiveness resides in the hypocotyl, it is 

 conquered by the Stimulus transmitted from the cotyledon. 



It is a pleasure to express my thanks to Miss Dorothea Pertz 

 who has given me a great deal of valuable help in carrying out 

 the experiments above recorded, also to Professor Seward, who 

 has been good enough to extend to me the hospitality of the Uni- 

 versity Laboratory. 



Cambridge, July 23rd, 1907. 



In experiments 9 and 18 the plants were fixed in tubes. 



