425 
Curvahire of Roots. 
and more distinctly as a dead mass of tissue, which eventually 
is sloughed off, as shown at x, Fig. 17. The tip of the radicle 
becomes regenerated in the course of a few days, and presents 
a nearly or quite normal appearance, though more or less 
pronounced traces of the wound, in the shape of a scar, 
curvature, or other deformity, may persist for an indefinite 
time. 
For the sake of clearness and brevity, reference has thus 
far been made only to the phenomena of traumatropism as 
seen in the radicles of seedlings ; their manifestation in 
secondary and aerial roots will be considered in subsequent 
pages. The literature of the subject is reviewed in connexion 
with the discussion of experimental work. 
Material and Methods. 
The experiments reported in the following pages were 
continued through seven months, during which time hundreds 
of specimens were observed under different external con- 
ditions, which were carefully noted. Every effort was made 
to exclude sources of error by the use of control plants, the 
rejection of imperfect or diseased specimens, and the repetition 
of observations. 
In the course of the work many different species were 
experimented upon, but the most prompt and satisfactory 
results were obtained with the primary root (radicle) of seed- 
lings of Angiosperms, among them Lupinus albus , Vicia Faba , 
Pisum sativum , Ricinus communis , and Zea Mais , and the 
aerial roots of Vitis gongy lodes and various species of 
Anthurium. 
The different ways of wounding already referred to, and 
some others, have been followed. The most convenient 
method consists in the use of a small glass rod, heated to 
redness in the flame of a Bunsen-burner, and then brought in 
contact for an instant with the part of the root that it is 
desired to cauterize. Metallic copper and nitrate of silver 
serve the same purpose, but it is more difficult to limit 
exactly their action, and the results are, to a corresponding 
