510 TRANSACTIONS OF SECTION D. 
by the yolk-glands. What the function of the ‘shell-gland ’ is remains unknown. 
The old question of the homology of Laurer’s canal in the Trematodes and 
Cestodes has been raised anew, and Odhner has revived the earlier view that the 
Cestode vagina is the homologue of the 'Trematode Laurer’s canal. Perhaps the 
most interesting new discovery is the existence of a communication between the 
intestine and the excretory vesicle in certain species of digenetic Trematodes. 
From the medical and veterinary point of view most attention has been paid to 
Ankylostomiasis, Schistosomiasis (Bilharzia disease), hydatid disease, and the 
relation of intestinal worms to intestinal diseases in general. In regard ta 
these many new discoveries of far-reaching importance have been made. 
--——____-_ -——_- - -—_-«--_- 
TUESDAY, SEPTEMBER 10. 
The following Paper was read :— 
Zoological Results of the Scottish National Antarctic Expedition. 
By Dr. W. 8S. Bruce, F.R.S.E. 
Joint Discussion with Section K on the Origin of Life. Introductory 
Remarks, by Hi. A. Mincntn, M.A., F.R.S. 
The problem of the origin of life involves two inquiries, both at present of 
a speculative order : the first, as to the nature and characteristics of the earliest 
living beings; the second, as to the manner in which the primordial form of life 
took origin and maintained its existence upon the earth. 
I. The cell, which may be defined as an individualised mass of protoplasm 
containing at least one nucleus, has generally been regarded as the simplest type 
of organism, the vital unit in the composition of living beings, whether plants or 
animals. It is, however, improbable that the earliest forms of life came into 
existence as organisms composed of two distinct and separate structural elements, 
the nucleus and the body-protoplasm or cytoplasm. Which, then, is to be 
regarded as representing or containing the most primitive elements of the living 
substance, the cytoplasm or the nucleus? 
By most biologists the cytoplasm has been considered to represent the true 
living substance. The earliest living beings have been supposed to be formless 
masses of protoplasm without nuclei, so-called Monera. There are, however, 
many reasons for believing that the chromatin-substance, invariably present in 
the nucleus, or occurring as grains, chromidia, scattered in the cytoplasm, repre- 
sents the primary and essential living matter. In support of this view may be 
urged :— 
(1) The fact that chromatin is always present in the bodies of living organisms 
of all kinds. : 
(2) The experimental proof that cells cannot continue to live if deprived of 
their nuclei. 
(3) The fact that in reproduction by fission the chromatin divides first, and 
is distributed among the daughter-individuals; karyokinesis may be regarded 
as a mechanism gradually evolved and perfected to ensure an exact quantitative 
and qualitative partition of the chromatin between the daughter-nuclei. 
(4) The relation of the chromatin-substance to syngamy and probably to 
heredity. 
(5) The part played by the nucleus in the production of ferments in the cell. 
(6) The fact that in the minutest living organisms the body appears to consist 
mainly or entirely of chromatin, cytoplasmic elements being either reduced to 
a minimum or absent altogether. 
For these reasons I regard the chromatin as the primitive living substance, 
and hold the view that the earliest forms of life were very minute particles of 
chromatin, round which in the course of evolution achromatinic substances were 
