incidental, and when they appear are turned to account for the benefit of the living. Now this is precisely what we have found (though at the date of the finding I was not in possession of the view of nature which I am now insisting upon). We have found that when material elements existed free in the celestial spaces, each invested with its full complement of ætherial atmosphere, that is, in circumstances most favourable for a most perfect synthesis into the most perfect molecules, they had been so framed at first as to give to nature first of all hydrogen, followed by common and then by ammoniacal vapour, and thereafter by carbon and phosphorus-in a word, those very elements which most properly receive the name of organic. Nay, further, we found that the very first phenomena of the condensation of vapour, the primal weaving of the clouds of the first morning in the sky, was a preluding in structure and a preparation for organic tissue (see p. 95).

It was afterwards, in the abyss, where the material elements existed under greatest pressure, most closely packed together, and with the æther proper to each most nearly extruded from them, that we found that the mineral elements were being formed--those elements which, comparatively speaking, may be regarded as dead.

Great violence, then, is done to the order of nature and to the cause of true science when the attention of the student is principally directed to the mineral elements, and organic chemistry is thrown into the position of an appendix.

It is for the sake of life that everything exists in nature, and so it ought to be in science.

Postcript.

Better diagrams of hydrocarbons, &c., than those given in Chaps. VIII. and IX. may be constructed by a still nicer manipulation of existing types.

INDEX.

The Roman numerals iii. ii. i. refer to Parts Third, Second, and First.
The common numerals to the pages in these Parts respectively.

m of the Principia of Newton, Tissue, genesis of, iii. 97.

ng conflicts in nature, ii. xviii. of Ultimate elements, iii. 6.