No. 606] BIOLOGICAL ENIGMAS 347 



origin of life can not be regarded as a catastrophic event; 

 life depends upon an organized complex of sheeted cat- 

 alytic material, and hence some life originates with each 

 new, successful mutation. Of course, if we trace the proc- 

 ess of the evolution of any given species back sufficiently 

 far, we must eventually come to the first mutation, which 

 would consist in the molecular production of an auto- 

 catalytic particle sustaining relations with its environ- 

 ment such as to make possible its continued growth and 

 reproduction. I have used the name protase to stand for 

 the ''first enzjTue" of the archebiotic process, but there is 

 no particular reason for supposing that there was only 

 one enzyme to which this name could apply. 



There is considerable evidence that free autocatalytic 

 enzymes exist in our biological universe even at the pres- 

 ent day. Such an hypothesis would serve to account for 

 the specific contagious diseases, such as measles, rabies, 

 and smallpox, which have been demonstrated to possess 

 "filterable viruses." The so-called Chlamydozoa prob- 

 ably fall in this class. 



That the Chlamydozoa consist of free chromatin ma- 

 terial is suggested by the late Professor Minchin, in his 

 admirable paper on the evolution of the cell,^^ with the 

 main outlines of which the enzjTue theory would entirely 

 agree. The single cell, and so-called simple protoplasm, 

 must be regarded as the products of a detailed process of 

 evolution, and hence can not form the ultimate explanatory 

 units in biology. Next to the free autocatalytic particle, 

 the simplest t\i)ical life-structure would consist of a single 

 particle of this sort surrounded by an envelope of semi- 

 liquid and chemically homogeneous substance with which 

 it sustains a heterocatalytic relationship. The most 

 primitive substance of this kind might be called eoplasm, 

 to distinguish it from complex protoplasm, and the phys- 

 ical system made up of protase and eoplasm would repre- 

 sent a living cell in its most reduced form. 



Minchin says, in the article referred to 



53 Minchin, E. A., "The Evolution of the Cell," American Naturalist 

 (1916), 50, 5-39, 106-119. 

 8* Loc. cit., 35-36. 



