CHAP. III. OF THE EADICLE OF CUCURBITA. 169 



were just touched with dry caustic on one side. Aftei 

 only 5 h. 10 m. five of them were slightly curved 

 from the perpendicular and from the side bearing the 

 little blackish marks. After 8 h. 40 m., 4 out of 

 these 5 were deflected at angles between 15 and 65 

 from the perpendicular. On the other hand, one 

 which had been slightly curved after 5 h. 10 m., now 

 became straight. After 24 h. the curvature in two 

 cases had considerably increased; also in four other 

 cases, but these latter radicles had now become so 

 contorted, some being turned upwards, that it could no 

 longer be ascertained whether they were still curved 

 from the cauterised side. The control specimens ex- 

 hibited no such irregular growth, and the two sets 

 presented a striking contrast. Out of the 8 radicles 

 which had been touched with caustic, two alone were 

 not affected, and the marks left on their tips by the 

 caustic were extremely minute. These marks in all 

 cases were oval or elongated ; they were measured in 

 three instances, and found to be of nearly the same 

 size, viz. of a mm. in length. Bearing this fact in 

 mind, it should be observed that the length of the 

 curved part of the radicle, which had become deflected 

 from the cauterised side in the course of 8 h. 40 m., 

 was found to be in three cases 6, 7, and 9 mm. 



Cucurbita ovifera : Sensitiveness of the apex of the Ra- 

 dicle. The tips proved ill-fitted for the attachment of 

 cards, as they are extremely fine and flexible. More- 

 over, owing to the hypocotyls being soon developed 

 and becoming arched, the whole radicle is quickly 

 displaced and confusion is thus caused. A large 

 number of trials were made, but without any definite 

 result, excepting on two occasions, when out of 23 

 radicles 10 were deflected from the attached squares 



