Biosophy 
found that atoms are approximately spherical, and their 
density increases with atomic weight, that of lead being 
about 14. times that of hydrogen, and a hydrogen atom 
being about 30 times denser than an electron. 
83. Molecules, according to Kleeman, tend to be 
much flattened spheroids, the flatness increasing with 
increasing molecular weight. Simple gaseous molecules, 
such as CO2, have a diameter of about 1/3000 micron, 
and in gases at normal temperatures are about 1/400 
micron apart. A proteid molecule with 2,300 atoms 
might have a diameter of some 1/200 micron, and in 
the collodial condition proteid is probably an aggrega- 
tion of such masses. The limit of microscopic visibility 
is about 1/6 micron: the organism of cattle pleuro- 
pneumonia has about this diameter; but invisible forms 
are known, such as the yellow fever organism, which 
cannot well exceed 1/10 micron, 
8. Protoplasm. 
studies in enzyme action, regarded the protoplasmic 
complex as built up of a series of associated templates, 
which serve as patterns to determine change in the 
various directions necessary for the maintenance of 
vital processes and of growth. Similar ideas were 
expressed by Ehrlich, who regarded the photoplasm 
molecule as composed of a central executive group and 
a series of side chains or “receptors,” which latter fit 
the food particles, enzymes, etc., in the way a key fits 
its lock. - 
85. A multicellular animal, from the point of view 
I am taking, may be regarded, in respect of a great part 
of its essential living structure, as a single gigantic 
chemical molecule, but as containing within that 
structure numbers of more or less independent mole- 
cules. For example, in man, I should regard the whole 
central nervous system as-part of this molecule, at any 
rate so far as a linking in the form of chemical linking 
extends, and I do not know to what extent such linking 
may extend beyond the boundary of the central nervous 
system proper through the nerves, nerve connections, 
muscular system and sense organs. At the other extreme 
blood corpuscles may be taken definitely as independent 
molecules contained within the main complex. 
86. The places in the universe in which a high 
degree of chemical complexity and life in its developed 
form are possible are, relatively speaking, extremely few 
and far between. In the stars, for the most part, simple 
chemical compounds cannot exist, and in the hottest 
stars even atoms are to a large extent dissociated. At 
lower temperatures chemical compounds become pos- 
sible, but very seldom could the precise conditions occur, 
such as are found on the earth's surface, favoring the 
development of life as we know it. No doubt life as we 
know it has evolved to suit the earth's environment; but. 
granting that organic evolution could occur under 
different, perhaps widely different, conditions, even then 
the spots where such might conceivably take place must 
be exceptional to an extreme degree. Apart from the 
doubtful exception of a few neighboring planets, no 
possible abode of developed life exists within a distance 
from the earth which it would take a ray of light, 
Armstrong, as a result of his 
travelling 300,000 kilometres per second, over four 
52 
years to penetrate. 
87. The characteristics of living matter have been 
summed up as adaptation, or, as Herbert Spencer defined 
it “the continuous adjustment of internal relations to 
external relations." These characteristics include 
assimilation, respiration, energy discharge, growth, re- 
production, and death. Organisation is one of the 
distinctive features of living beings. 
88. The proposition that life is a function of 
molecular complexity is, in the light of recent advances 
in bio-chemistry, almost a truism, and I do not think 
that many biologists would dispute it in that form. 
But when one goes further and suggests that there is, in 
ihe structure of certain elements, most of them of low 
atomic weight, and particularly in carbon atoms, a 
potentiality capable of bringing about, in suitable con- 
ditions, the development of organisms recognisable as 
“living,” then one can only say that the suggestion 
appears the most reasonable working hypothesis al 
present available. But, to establish the suggestion as 
something more than a working hypothesis, more solid 
support is necessary. It is well within the bounds of 
probability that such support may at any time be forth- 
coming; for all I know research in this direction may 
already be progressing. It will be no surprise if 
bio-chemists succeed within the next hundred years in 
synthesising a low form of living protoplasm; although, 
no doubt, the approach to such a synthesis will be long 
and tedious. The progress in the past hundred years 
has been sufficient to justify such a forecast. 
89. It is no exaggeration to say that biologists now 
accept with absolute conviction the theory that since 
pre-Cambrian times, some thousand million years ago, 
lowly forms of life, probably unicellular Protozoa and 
Protophyta, the only forms of life then existing, and of 
microscopic dimensions, have by a process of evolution, 
by inheritance and variation and without external influ- 
ence other than an enviroument roughly corresponding 
io the environment we now experience, given rise to all 
the forms of plants and animals now living, man 
included. The establishment of this theory has been the 
work of science in little more than the last hundred 
years, and is a more astounding achievement than would . 
be the establishment of a similar and preceding evolution 
from carbon compounds to “living” protoplasm, 
90. Equally striking is the evidence to be found in 
the development of each human being in his or her own 
life from the minute fertilised ovum to the adult form, 
for here every successive stage can be seen and examined 
in minute detail under the microscope. The range of 
evolution thus recapitulated in the individual human 
being is surely comparable in extent to the range of 
evolution postulated in this chapter between carbon 
compounds and protoplasm. i 
91. The difference in time scale is enormous, 
between the slow evolution by which, in the course of 
countless generations the pre-Cambrian protozoon gave 
rise to modern man, and the rapid individual develop- 
