STRUCTURE AND HISTORY OF PLAV. 255 
whose work marks the beginning of a new period in the study of plants, for, 
henceforth, the question of senility can no longer be ignored in the plant 
realm, but will have to be considered by workers in every branch of 
botany. Professor Benedict published a short, but important, paper on 
senile decay in plants in March 1912, seven months before I began my 
work on the reed, and another longer one in June 1915. The line of 
study he pursued differed widely from mine, for not only was his material 
different, but his work, unlike my own, was undertaken with a direct view 
to the solution of this question. The question as he framed it was: does the 
meristem of perennial plants retain its embryonic character unchanged ? 
Professor Benedict answers this question by the statement that in perennial 
plants the leaf (according to my conception a portion of the minor individual) 
undergoes a definite progressive change in accordance with the age of the 
plant that has borne it, and he explains how this portion of the “minor 
unit” apparently indicates that there is a natural limit to the life of the 
* major unit,"—in fact, his studies lead him to believe that plants die owing 
to senility. Не sums up (in his 1912 paper), with the advice to plant- 
breeders not to put their trust in cuttings in the case of plants that naturally 
reproduce from seed, but to develop fresh plants from seed. 
The theoretical question: what constitutes the vegetable individual— which 
is so closely connected with the question of senescence and death—was 
frequently debated during the early part of the last century * and has recently 
again been under discussion, as also that of the animal individual. In the 
Contemporary Review for September 1913 f there was an interesting article 
on the plant individual, and the writer evidently believed that he had raised 
the question for the first time; the late M. Fabre, the entomologist, also 
discusses it in the introduction to Botany which he wrote for his son f ; 
while on the Zoological side there is Professor Julian Huxley’s * The 
Individual in the Animal Kingdom” $. Usually it is either the * minor " or 
the “major” individual which is discussed directly, in which case the other 
unitis usually implied, and appears, in fact, as a shadowy and incomplete 
part or whole, as the case may be. 
* Du Petit-Thouars, A. A., * Essais sur la Végétation considérée dans le Développement 
des Bourgeons.” Paris, 1809. 
Gaudichaud, Charles, “ Recherches générales sur l'Organographie, la Physiologie et 
l'Organogénie des Végétaux." Paris, 1841. 
Braun, Alexander, translated by C. P. Stone, “The Vegetable Individual in its relation 
to Species," The American Journal of Science and Arts, 2nd ser. vols. xix. & xx. (1855) and 
xxi. (1856). 
Gray, Asa, “Introduction to Structural and Systematic Botany and Vegetable Physio- 
logy,” 5th revised edition of the Botanical Textbook. New York, 1860. 
+ Davidson, H. C., * The Nature of Plants," Contemporary Review, Sept. 1913. 
і Fabre, J. H., “Га Plante," 10th edition, Paris. 
$ Huxley, J., “ Тһе Individual in the Animal Kingdom." Cambridge, 1913. 
