606 D. T.. MACDOUGAL 
living matter which might perpetuate itself and evolve into differen- 
tiated forms will long remain one of the most difficult feats which 
confronts the experimenter. The tests and criticisms which have 
been applied to the results of the few essays that have been made 
for the production of bodies which would be self-maintenant in a 
suitable medium, have been, for the most part, misdirected. Thus 
in the consideration of the hitherto unsuccessful efforts to produce 
bodies simulating some of the properties of self-generating matter, 
tests for the physical and chemical properties of protoplasm as well 
as for phenomena of the cell have been applied, regardless of the 
fact that the cell probably stands removed by a million years of 
evolution from the simple living material which first took shape, 
and represents, in fact, simply a successful form of organism and by 
no means the only possible morphological organization. 
Such misuse of criteria has doubtless operated to curb research 
and discourage experimentation, and while it may have seemed 
soundly conservative for Kelvin to say: 
But let not youthful minds be dazzled by the imaginings of the daily news- 
papers that because Berthelot and others have thus made foodstuffs they can 
make living things, or that there is any prospect of a process being found in 
any laboratory for making a living thing... . . There is an absolute distinction 
between crystals and cells. Nothing approaching to the cell of a living creature 
has ever yet been made, 
yet the actual accomplishment of self-generating matter is, as sug- 
gested above, a theoretical possibility in the laboratory. The pro- 
vision of a proper nutritive environment would present greater 
difficulties than the construction of a thermo-catalyzer capable of 
sustaining itself in a proper medium. 
After growth and decay, the next most important property of 
living matter is that of irritability, of impressibility, and of accommo- 
dation to environment. The basic substance of protoplasm endured 
because of a capacity for withstanding the current range of tem- 
perature and insolation, and this endurance was made possible by 
fairly automatic adjustments, one of the simplest of which is encoun- 
tered in recognizable form in living plants today in the decrease of 
water content, following lower temperatures acting upon proto- 
t Nature, XXXI, 13, 1904. 
