62 SECTIONAL ADDRESSES. 



pouring into the air C0 2 from the bowels of the earth, coal-plants and cal- 

 careous animals have buried in solid form the carbon from many thousand 

 times the quantity of C0 2 which we have now in the atmosphere ; it is 

 therefore probable that the alkalinity of the sea, and the dissolved 

 calcium, have varied considerably from epoch to epoch. If all the surface 

 of the globe were one continuous meadow, evenly producing a ton of hay 

 an acre annually, I make out that in twenty-five years it would have 

 fixed as much carbon-dioxide as there is in the atmosphere, and in 15,000 

 years it would produce as much free oxygen as we have in the world to-day. 

 We see, therefore, that the advent of photo-synthetic protein in the ocean 

 must itself have changed the physiology of the world very considerably, 

 and that the change in conditions, after a million years' duration of the 

 lowest form of life, rendered the world capable of supporting organisms 

 which would have been impossible at the beginning of that age, and 

 conceivably rendered it incapable of supporting ever again the first 

 forms of life. 



Of the possible genesis of the first form of life we heard from Dr. Allen 

 at Hull. To-day let us take up the tale, in the warm Pre-Laurentian 

 sea, with little fragments of protein lying in the sunlit waters. Each 

 fragment is continuously receiving energy — whether from the sun, accord- 

 ing to Professor Baly's theory of activation, or from some other electro- 

 magnetic source — and with that energy is building up the molecules of 

 the surrounding solution into molecules of protein, so that the fragment 

 grows. 



The supply of energy is continuous, and the supply of solution is con- 

 tinuous, yet growth of the fragment of protein cannot be continuous, 

 because number is discontinuous. A growing fragment contains 100 

 molecules of protein, presently it will contain 101, then 102. It may be a 

 thousandth of a second, it may be an hour between the moment of attain- 

 ing 100 and the moment of attaining 101 molecules, but with a constant 

 supply of energy it will be closely the same interval after acquiring the 

 101st molecule and before the 102nd is added. Let us suppose that the 

 interval has been 10 seconds. What will be happening during the next 

 ten seconds before the molecules number 103 ? 



The continuous supply of energy must in some form be stored in the 

 102 molecules until its total is adequate to compel the combination of the 

 water, carbon, nitrogen, sulphur and the rest of it into the new 103rd 

 molecule of protein. This stored energy is then spent in forming the 

 combination, and for another 10 seconds the 103 molecules accumulate 

 gradually a sufficient supply to force the combination of a 104th molecule. 

 We cannot suppose that the molecules can store energy except by a change 

 of atomic or electronic arrangement, nor that such change fails to affect 

 their molecular volume. Expansion of molecular volume means storage 

 of energy which is released on contraction ; we may feel sure that even if 

 the main storage of energy be in some other form, it will at least be accom- 

 panied by expansion in volume and surface. When energy is given up to 

 form the new molecule, all the old ones will return to their original volume, 

 and if their expansion was by more than one-hundredth of their volume, 

 the whole fragment will contract. 



A slow expansion while energy is being accumulated, a rapid but 



