428 TRANSACTIONS OF THE CANADIAN INSTITUTE. (VoL. VIII. »' 
phycez possess that power as Beijerinck* has pointed out and these, 
though primitive in their structure are ofa so highly specialized vegetable 
character as to preclude their being considered as the forms from which 
both animal and vegetable organisms arose. Unless there were more 
than one form which reached the earth from far distant stellar systems; 
the organism which started life on the earth must have been very simple 
and neither animal nor vegetable definitely in its metabolic processes, in 
fact, in the latter respect like the Peridinez which are also remarkable 
in that in them is found an exceedingly primitive type of nuclear 
division which, with their metabolism, indicates that they are very 
archebiontic in character. Whether they assimilate free nitrogen is not 
known. 
It must be admitted that there are in the Panspermic Theory 
difficulties which are not overcome in explaining how the primal organ- 
ism or organisms could reach the earth from far distant planetary 
systems, difficulties which are concerned in understanding how an 
organism itself of an indifferentiated character, even if it escaped de- 
struction in transit, could find a terrestrial medium which would permit 
it to thrive and reproduce itself. 
Because of these difficulties one turns to the theory of the origin of 
life on this planet which postulates that its first living form arose as the 
product of the action of physical and chemical forces on the constituents 
of the water and the atmosphere at a certain time in the history of the 
globe. This mode of origin is sometimes referred to as spontaneous 
generation but that name has so invidious a history and has been in 
the past associated with such extravagant speculations that it would 
perhaps be wise to abandon it and adopt another. It is further not a 
defensible name for in no sense can life be regarded as spontaneously 
produced on the globe to-day and the term “spontaneous” when used in 
this respect implies that living forms may arise de novo out of non-living 
matter at any time under the ordinary physical and chemical conditions 
which now obtain. The view so implied is not a defensible one as we 
shail see presently and it is well, therefore, to avoid the use of termin- 
ology which carries with it such an implication. 
Aristotle was the first who definitely advanced the view that living 
organisms first arose spontaneously, but the view was held in a more or 
less inchoate form by the Greek philosophers from Thales onward. 
The poet, Lucretius, expressed this view when he said that “the earth 
*M. W. Beijerinck—‘ Further Researches concerning Oligonitrophilous Microbes,” Kon, Akad, van 
Wetensch., Proceedings, Vol. 4, p. 5, 1901-2. 
