October 31, 1890.] 



SCIENCE. 



241 



years the truth of his discovery was denied by philosophers; 

 but the chemists pursued the even tenor of their ways, multi- 

 plying continually the number of organic substances arti- 

 ficially formed, until to-day the field of organic chemistry 

 has manifold more investigators than that of its elder sister, 

 inorganic chemistry. Thousands, we might say millions, of 

 organic substances have been formed. The dye-stuffs turkey- 

 red and indigo, as well as hundreds of the aniline dyes so 

 called, the formation of which Dame Nature has never 

 attempted, and many alkaloids, are chemistry's best repro- 

 ductions of nature's work; and within a few months grape 

 and fruit sugar have yielded up their secrets. Few will be 

 the years, perhaps months, before even cane-sugar, and 

 morphine and quinine, will be in the list of the chemist's 

 triumphs. Indeed, there is hardly a substance which 

 nature can form that the chemist despairs of reaching. And 

 why not, when we consider that the same forces are at his 

 disposal which Nature uses in her laboratory? Life is 

 merely the director of these forces. Nevertheless we are not 

 to consider, however great may be his attainments, that the 

 chemist will ever form life itself. The living protoplasmic 

 cell is something more than a complicated aggregation of 

 complex molecules, that exists when life has left the cell ; 

 but not until we can make alive the protoplasm from which 

 life has just departed can we hope to pass in our laboratories 

 beyond the making of dead protoplasm. 



Coming down to a date a little later than that of Wohler, 

 we meet the third great generalization, — that of the conser- 

 vation of energy. Long after the idea of the permanence of 

 matter had permeated science it was still belie v'ed that en- 

 ergy was controlled by no such law. The revolving wheel 

 came to rest a moment after the force ceased to be applied; 

 the rifle-bullet struck the wall, and its energy left it; the 

 stone fell into the water, made a splash, and in a moment 

 all was at rest (the energy in the stone had disappeared). 

 It was only when it was realized that heat was merely a 

 form of motion, — motion of the atom and molecule, and not 

 of the mass, — that the conception became possible that en- 

 ergy, like matter, was imperishable. The wheel indeed 

 stops, but its motion is lost by friction, and converted into 

 heat: the molar energy has merely become molecular and 

 atomic. The rifle-bullet has stopped, but it is hot, and the 

 lost motion of the bullet is now making move more rapidly, 

 and through longer paths, the molecules and atoms of the lead. 

 The stone has fallen, but the water into which it fell has 

 been warmed by that transferrence of energy; and it was 

 Joule who showed that the heat which the water has re- 

 ceived can be converted back into molar motion, and is just 

 sufficient to raise the stone to the height from which it fell. 

 Thus, while energy appears in protean forms, it is never 

 lost; and this law we find to be no less true in the inorganic 

 world than in the world of life. The work we do, and the 

 heat of our bodies, are the exact equivalents of the combus- 

 tion of the food we eat, with the oxygen of the air we 

 breathe. This law has, since its discovery, formed a crite- 

 rion in the judgment of the efficiency of all kinds of ma- 

 chinery, enabling the determination of the proportion of the 

 energy applied as fuel or otherwise, which is utilized ; and 

 thus it further enables the saving of great amounts of energy 

 by showing where the loss lies. 



The acceptance of the fourth and last of the great gener- 



alizations of science is within the memory of most of my 

 audience. I refer, of course, to the idea of evolution. That 

 there had been a progressive development of species of 

 plants and animals from their first appearance on the earth, 

 was long ago believed. It was taught in the Arabian 

 schools during the dark ages of Europe: we even find it 

 hinted at in the apocryphal books of the Old Testament. 

 Lamarck tried to explain it, and Darwin's illustrious grand- 

 father seemed imbued with the theory. Goethe was on the 

 verge of its discovery. But it remained for Charles Darwin 

 to so present the evidence and to explain the plausibility of 

 its truth, that the world of science should come to believe 

 that evolution is a fact. More, perhaps, than any of the 

 three earlier great generalizations of which I have spoken, 

 was that of evolution far reaching in its influence. In little 

 more than a quarter of a century we have seen the idea of 

 evolution permeate the fields of history, philosophy, law, 

 politics, philology, and even theology. It matters not in 

 our present consideration whether or no it be a fact that 

 man was developed from a lower form of life, whether or 

 no life originated spontaneously from inorganic matter. 

 These are points to be settled by evidence; and as to the 

 evidence, scientists difter. These are but very special and 

 minor applications of the generalization. The great idea 

 which evolution emphasizes is that Nature does not move 

 per saltum, but is uniform in her working; that God works 

 according to what we call laws, and not arbitrarily, and 

 that he will not suffer his highest creation, man. to be put 

 to permanent intellectual confusion. In the application of 

 evolution, Darwin sought to show how it was probable the 

 development of organic nature was brought about. This 

 does not affect the question of development of itself, which 

 is a question of fact, to be accepted or rejected according to 

 evidence. It has been accepted by the vast majority of all 

 scientists; but the present work of biologists is to philoso- 

 phize, as did Darwin, as to the why of evolution. He pre- 

 sented as chief cause the survival of the fittest in the struggle 

 for existence; he later added sexual selection as a powerful 

 factor; and other naturalists have proposed many other 

 causes, more or less far-reaching in their influence. 



Thus the study of evolution in the organic world to-day 

 is a philosophy of evolution; and we may say that thus far 

 there is comparatively little agreement among the philoso- 

 phers. It remains as a great problem of the future, the so- 

 lution of which perhaps none of us will see. 



It is perhaps more to evolution than to any of the other 

 great generalizations that the great progress science has made 

 in the last quarter of a century is due; not, indeed, to its- 

 direct influence, but rather to the stimulus and impetus it- 

 has given. It perhaps might be said with truth that science 

 has made more progress during each decade of the present 

 century than it had made in all time previous to the opening 

 of that c^ecade. This is particularly true of the last ten 

 years. While the advance here has been most lai'gely in 

 the realm of applied science, yet one discovery in the field of 

 pure science ought not to be omitted, which may yet prove 

 to be more far-reaching than we yet anticipate. I refer to 

 the demonstration by Herz. that electricity, like heat and 

 light, is a form of vibratory motion of what we call the 

 luminiferous ether. To be sure, for many years it has been 

 foreseen that this must be the case; but yet, when the dem- 



