397 
Bayliss . — On the Galvanotropism of Roots . 
of electrolysis in the cell-sap, since a similar thickening frequently appeared 
in the neighbourhood of the stimulated spot when radicles curved as the 
Fig. 3. Roots showing an abnormal thickening. 
result of the external application of acid 
thickening took place when the tips of 
broad beans were allowed to grow against 
a pellet of blotting-paper saturated with a 
very dilute solution of sodium carbonate 
(Fig- 4 )- 
Nemec 1 in a recent paper drew at- 
tention to a thickening of roots in the 
strongest growing part produced by allowing 
them to grow for an hour in a solution of 
either chloral hydrate or benzine, and then 
transferring to pure water : after forty-eight 
hours or so the normal growth was resumed 
again. 
or alkali. The same kind of 
Fig. 4. A root of Broad Bean, 
showing an abnormal thickening due 
to growing against a pellet of blotting- 
paper saturated with dilute sodium 
carbonate. The curve is geotropic. 
9. Abnormally Elongated Cells. 
There should be mentioned another feature which was to be seen when 
any injury extending two or more cells below the epidermis occurred. 
To the naked eye nothing was apparent except a brown scar, but 
microscopic examination revealed cells, two or three rows deep, with 
greatly extended radial walls ; and between these cells and those forming 
the endodermis the cells were of the normal size, though the protoplasm in 
them appeared to have contracted and was probably dead. A few of 
these cells when measured had radial walls of lengths *51 mm., -68 mm., 
•85 mm., and 1*53 mm., compared with the normal diameter of -34 mm. 
or *51 mm. : the tangential walls were nearly normal, and did not differ 
much from one another. 
Injured places on roots which had been made to curve by the external 
1 Nemec, Pringsheim’s Jahrbiicher, vol. 39, p. 689. 
