304 ATMOSPHERIC FACTOR IN EVOLUTION. 



But they also grind smoothly : there is no jolting of the machin- 

 ery. In my opinion evolution according- to Darwin proceeds by 

 a long series of small jolts. It lacks the smoothness of Nature's 

 •other laws. The ancients recognised this smooth way of 

 Nature's workings. They expressed it thus in Latin : " Natura 

 non facit saltuni." Nature does not progress by leaps and 

 bounds. 



According to my theory, the dominant factor in evolution, the 

 steady withdrawal of carbon from the atmosphere has mainly 

 brought about the correspondingly steady change in the animal 

 organism. Everything that has lived in the past has added its little 

 to the steady stream of evolution. The Classical quotation which 

 best sums up my views on evolution is not the Latin one already 

 already given, though it fits it, too, but the Greek one, Trai-o pet 

 is true in a double sense. Its usual meaning is that everything 

 :is in a state of flux or is changing. Of course, this is true of 

 everything in Nature. But the special meaning I give it here is 

 that everything is follow-ing on, everything is helping on the 

 steady flow of evolution. In this sense Trorra pei cannot be 

 said of Darwinism. 



Before closing the consideration of my objections to Darwin- 

 ism, I will repeat one that I made at the start, namely : that Dar- 

 win admits that he can offer no explanation of the origin of those 

 varieties which he says survives. Prof. Arthur Thomson admits 

 tihat Darwin has no explanation to offer of the growth of the tree 

 of evolution. He puts it thus: "Natural selection prunes a 

 growing tree." Darwinism, then, explains the use of the pruning 

 knife, but makes no attempt to explain the growth of the tree, 



I think that I havie shown how the general law which I have 

 enunciated, the law which has worked in every living thing 

 steadily through the ages of the past, has brought about the 

 growth of the tree of evolution. 



Just a word in conclusion as to the factors in their evolution. 

 I have been constantly mentioning one, that is the steady with- 

 drawal of carbon from the atmosphere. I 'have done so because 

 :so far as I know it is the only factor that has worked so steadily 

 in the same direction through all the ages. Other factors have 

 been at work, such as alterations of heat and cold, drought or 

 famine alternating with plenty, but these changes were of the 

 nature of slight oscillations and did not help on much the pro- 

 gress -of evolution. From these alternating conditions we have 

 a change of external conditions of a totally different nature in 

 tihe tremendous change in the atmosphere. Here we have as 

 complete a swing of the pendulum as it is possible to conceive : 

 not a large number of little oscillations, but one long, steady 

 swing of the pendulum from much carbon-dioxide and little or no 

 oxygen to the other extreme of much oxygen and no carbon 

 dioxide. 



It is for this reason that I say that Atmospheric Variation has 

 been the dominant factor in organic Evolution, To return for a 

 moment to the rather pessimistic conclusion at which I arrived at 

 the end of the first part of this paper, namely : that at a date not 



