44 
SPECULATIONS ON PROTOPLASM. 
it is now known that the crude and simple idea of a cell, on 
which the hypothesis was founded, falls far short of represent¬ 
ing its real complexity. A series of papers about to appear 
in the “ Midland Naturalist,” from the able pen of Professor 
Hillhouse, of the Mason College, will render this point 
clear. 
The speculation has been carried still farther. It is 
pointed out that to suppose consciousness and life to be con¬ 
fined to the planet on which we dwell is an improbable 
assumption. The idea of a plurality of worlds has had a 
fascination for many minds of the highest rank. But it is 
obvious that, if living beings exist in the other planets of our 
solar system, they cannot be composed of what we call proto¬ 
plasm. In Mercury, for instance, our fundamental basis of 
life would be resolved into its component gases, and in 
Saturn would be frozen into a hard and dense solid, “ of 
which edge-tools might be made.” The protoplasm of one 
planet cannot, therefore, be identical with that of any other 
planet. 
In the “ Principles of Biology,” Herbert Spencer shows 
that the peculiar fitness of organic substances, as we know 
them, for forming the vehicle of life, resides in their many- 
atomed chemical composition and consequent molecular insta¬ 
bility. But these qualities are not necessarily confined to 
protoplasm. We can, indeed, partly see why our protoplasm 
is constituted as it is. Carbon, oxygen, hydrogen, and nitro¬ 
gen are abundant in our atmosphere, with its proportions of 
carbonic acid gas and watery vapour, and are consequently 
brought with ease within the reach of every living thing.* 
But it is not difficult to imagine that, with other environment, 
matters might be quite different, and yet the essential prin¬ 
ciple of organic chemistry remain the same. In our case, 
certain molecules are deoxidised in a vegetable cell, and then 
reoxidised in an animal, and there is no reason why this 
mutual interchange of function might not take place with 
other oxides for its basis. In fact, wherever heat is found, 
there life is possible. Only when the last dim ray from 
cooling suns lias winged its way across the illimitable void, 
when the last foot-pound of energy is dissipated into the 
depths of space—only then need the cold and pulseless 
universe feel the final throb of life. 
W. B. G. 
* The question, whether plants derive their nitrogen directly from 
the air, or from the nitrates, etc., in the soil, is here unimportant, as 
in either case it comes ultimately from the former source. 
