Q. E. D. | Page 3

chapters may clear up the doubts of some, and encourage the faith of many, is the object of their publication in this non-professional form.
G. McC. P.

Contents
I. MATTER AND ITS ORIGIN 15 II. THE ORIGIN OF ENERGY 31 III. LIFE ONLY FROM LIFE 43 IV. THE CELL AND THE LESSONS IT TEACHES 57 V. WHAT IS A "SPECIES"? 68 VI. MENDELISM AND THE ORIGIN OF SPECIES 78 VII. GEOLOGY AND ITS LESSONS 99 VIII. CREATION AND THE CREATOR 125

I
MATTER AND ITS ORIGIN
I
When we were told by a prominent scientist just the other day that "electricity is now known to be molecular in structure," it almost took our breath away. And when we were informed that certain well-known chemical elements had been detected in the very act of being changed over into other well-known elements, with the prospect of such a transformation of the elements being quite the normal thing throughout nature, the very earth seemed to be slipping away from under our feet. Some of the closely related discoveries, such as the fact that the X-rays show a spectrum susceptible of examination, were not so disconcerting in themselves; but the marvellous pictures of the structure of the atom elicited by these discoveries made many good people almost question whether our venerable experimenters had not been indulging in pipe dreams amid their laboratory work.
Do we, then, begin to understand the real composition of matter? Does it have component parts, in the materialistic sense; or is what we call matter only a mysterious manifestation of energy? And if the latter be our answer, can we hope to settle the problem objectively and so conclusively that it will stay settled? In short, do we, regarding these border-line subjects between metaphysics and natural science, know anything more than our fathers and our grandfathers?
It will be convenient to consider these problems under two heads: the composition of matter, and the origin of matter.
II
1. It was long ago recognized that matter must be composed of particles which are driven farther apart by heat and are brought closer together by cold, thus laying the foundation for the theory of the molecular composition of matter. But not until the time of Dalton, about a hundred years ago, was it proved that the molecule itself, the unit of physical change, is capable of definite division into atoms, the units of chemical change. This conception of the molecules and atoms as the ultimate units of which matter is composed maintained its place until the discovery of radioactivity and its associated phenomena, about 1896; since which time we have definitely ascertained that even the atoms are separable into still smaller units, and that possibly these units are all alike. On this last possibility, it would surely be a most amazing fact if such multitudinous "properties" of bodies could be produced merely by variations in the arrangements of these ultimate units into atoms, or in some other way which produces vast differences in properties by combinations of units that are nevertheless mere duplicates of one another.
As hydrogen is the lightest of the elements, it has been a favorite theory with scientists that the various elements are all composed of combinations of hydrogen atoms. But since many of the elements have atomic weights which cannot be made exact multiples of that of hydrogen, it has been felt that there must be some other smaller unit than the hydrogen atom; or else that these hydrogen atoms themselves change in weight when they combine to form other atoms. But mass seems to be the one unchangeable characteristic of matter; hence it was felt that any change of weight is almost unthinkable, and so a solution was sought in the direction of still further dividing the hydrogen atom, the smallest unit concerned in chemical change, as then understood. But now the facts and principles brought to light in connection with the studies of radioactivity have settled it that we actually do have a much smaller unit than the hydrogen atom, one of only about 1/1760 its mass, in fact; and that this smallest of the small things of nature is none other than a particle of negative electricity, now called an electron.
That the atoms of all the elements must have a common unit of composition, that they behave as if composed of ultimate particles that may be regarded as duplicates of one another, has long been regarded as an inevitable conclusion from the Periodic Law of Mendeleef. This law says that the physical as well as the chemical properties of the various elements depend upon their atomic weights, or as it is stated in the language of mathematics, the properties of an element are functions of its atomic weight. This fact of the variation in the properties of elements in accord with their atomic weights has been