562 REPORT—190. - 
Section K.—BOTAN Y. 
PRESIDENT OF THE Section—Harotp Wacer, F.R.S., H.M.1. 
The President delivered the following Address at Johannesburg on Tuesday, 
August 29 :-— 
Introduction. 
Wuen Robert Hooke, in the early part of the seventeenth century, discovered, 
with the aid of his improved compound microscope, the cell structure of plants, he 
little thought that our ultimate knowledge of the physical and chemical processes 
in the living organism, of its growth and reproduction, of the problems of heredity 
and of the factors underlying the origin of life itself, would be in the main depen- 
dent upon a clear understanding of the structure and physiology of the cell. 
Hooke’s researches did not, in fact, carry him very far, and we must turn to 
the nearly contemporaneous works of Malpighi and Grew on the anatomy of 
plants for the first clear indication of the important part which cells take in the 
constitution of the various tissues of plants. The account they give of them 
is extremely interesting in the light of our present knowledge. Grew, for 
example, in speaking of the structure of the root, compares the parenchyma to a 
sponge, ‘being a body porous, dilative, and pliable . . a most exquisitely fine 
wrought sponge.’ The pores are spherical and consist of ‘an infinite mass of 
little cells or bladders. The sides of none of these are visibly pervious from one 
into another; but each is bounded within itself... . They are the receptacles. 
of liquor, which is ever lucid, and. . . always more thin or watery.’ There is no 
indication either in Grew’s or Malpighi’s works that they understood the significance 
of this cell structure, and it was not until the beginning of the nineteenth century, 
after a lapse of some 160 years, that any insight into the real nature of the cell 
and its functions was obtained. But then began a period of activity—associated 
with the names of Turpin, Meyen, Robert Brown, Purkinje, J. Miiller, Henle,. 
Valentin, and Dutrochet—which culminated in the cell theory of Schleiden and 
Schwann that the common basis of all animal and plant tissues is the cell, and 
that it is upon this elementary vital unit that all growth and development: 
depends. 
PThe nucleus was discovered in 1831 by Robert Brown in various tissues of the 
Orchidesze and in some other families of the monocotyledons, as well as in some: 
dicotyledons. He described it as a ‘ single circular areola, generally somewhat 
more opaque than the membrane of the cell, and more or less granular. It 
is very distinct and regular in form, and its granular matter is held together by 
