930 



SCIENCE. 



[N. S. Vol. XI. No. 285. 



If variation was markedly greater in the 

 early periods of the existence of living 

 matter, it is clear that it would have been 

 possible for evolutionary change to have 

 been effected much more rapidly than at 

 present — especially when we remember that 

 the world was then comparatively unoccu- 

 pied by organisms, and that with the change 

 of conditions consequent on the cooling and 

 differentiation of the earth's surface, new 

 places suitable for organic life were con- 

 tinually being formed. It will be observed 

 that the conclusion we have now reached, 

 viz, that variation was much greater near 

 the dawn of life than it is now, and hered- 

 ity a correspondingly less important phe- 

 nomenon, is a deduction from the selection 

 theory. It becomes, therefore, of some 

 interest to inquire whether a suggestion 

 obtained by a perfectly legitimate mode of 

 reasoning receives any independent con- 

 firmation from other sources. The first 

 source of facts to which we turn for such 

 confirmation must obviously be paleon- 

 tology. But paleontology unfortunately 

 affords us no help. The facts of this sci- 

 ence are too meagre to be of any use. In- 

 deed, they are wanting altogether for the 

 period which most immediately concerns 

 us — namely, the period when the existing 

 forms of life were established. This took 

 place in the prefossiliferous period, for in 

 the earliest fossiliferous rocks examples of 

 almost all existing groups of animals are 

 met with. 



But although paleontology affords us no 

 assistance, there is one class of facts which, 

 when closely scrutinized, do lend some 

 countenance to the view that when evo- 

 lutionary change was at its greatest ac- 

 tivity, i. e., when the existing forms of life 

 were being established, variation was con- 

 siderably greater than it is at the present 

 day. 



But as this address has already exceeded 

 all reasonable limits, and as the question 



which we are now approaching is one of 

 very great complexity and difficulty, I am 

 reluctantly compelled to defer the full con- 

 sideration and treatment of it to another 

 occasion. I can only hope that the far- 

 reaching importance of my subject and the 

 interest of it may to some extent atone for 

 the great length which this address has at- 

 tained. 



Adam Sedgwick. 

 Cabibeidge Univeesity. 



THE PBOTEIDS OF LIVING 3IATTEB.* 

 Of all the phenomena of nature vital 

 phenomena have always appeared to the 

 human mind the most complicated and in- 

 tricate, so much so that even many scien- 

 tific men have ascribed them to an inexplor- 

 able cause — the so-called vital force. This 

 ' vitalism' is adhered to by many even to- 

 day. In scrutinizing the various vital 

 phenomena we observe, however, a great 

 difference in the degree of complexity. 

 There are on the one hand actions of an 

 admittedly purely chemical, physical, and 

 mechanical nature ; and on the other those 

 of organization, genetic differentiation, and 

 of irritability on which differences of opin- 

 ion still exist. The former appear of rela- 

 tively simple character compared with the 

 latter, which seem to offer difiiculties of ex- 

 planation insurmountable for science in its 

 present state of development. 



Protoplasm even of the simplest cells 

 represents a highly complicated machinery. 

 The organization corresponds to the con- 

 struction of a machine, while its motive 

 power consists in various forms of energy. 

 Hence, two principal questions arise : (1) 

 How is the machinery constructed ? (2) 

 What is the nature of the primary energy 

 moving the machinery ? The latter question 

 is of a simpler kind than the former. We 



* A paper read before the joint meeting o£ the Bio- 

 logical and Chemical Societies of Washington, May 5, 

 1900. 



