irst books in which our new knowledge of
organic chemistry began to be displayed, thirty years ago, I find that even
at that period the organic elements which the cuisine of the laboratory had
already detected in simple Indigo, were the following:-- {250}

Isatine, Bromisatine, Bidromisatine;
Chlorisatine, Bichlorisatine;
Chlorisatyde, Bichlorisatyde;
Chlorindine, Chlorindoptene, Chlorindatmit;
Chloranile, Chloranilam, and, Chloranilammon.

And yet, with all this practical skill in decoction, and accumulative
industry in observation and nomenclature, so far are our scientific men
from arriving, by any decoctive process of their own knowledge, at general
results useful to ordinary human creatures, that when I wish now to
separate, for young scholars, in first massive arrangement of vegetable
productions, the Substances of Plants from their Essences; that is to say,
the weighable and measurable body of the plant from its practically
immeasurable, if not imponderable, spirit, I find in my three volumes of
close-printed chemistry, no information what ever respecting the quality of
volatility in matter, except this one sentence:--

"The disposition of various substances to yield vapour is very different:
and the difference depends doubtless on the relative power of cohesion with
which they are endowed."[67]

Even in this not extremely pregnant, though extremely {251} cautious,
sentence, two conditions of matter are confused, no notice being taken of
the difference in manner of dissolution between a vitally fragrant and a
mortally putrid substance.

It is still more curious that when I look for more definite instruction on
such points to the higher ranks of botanists, I find in the index to Dr.
Lindley's 'Introduction to Botany'--seven hundred pages of close print--not
one of the four words 'Volatile,' 'Essence,' 'Scent,' or 'Perfume.' I
examine the index to Gray's 'Structural and Systematic Botany,' with
precisely the same success. I next consult Professors Balfour and Grindon,
and am met by the same dignified silence. Finally, I think over the
possible chances in French, and try in Figuier's indices to the 'Histoire
des Plantes' for 'Odeur'--no such word! 'Parfum'--no such word.
'Essence'--no such word. 'Encens'--no such word. I try at last 'Pois de
Senteur,' at a venture, and am referred to a page which describes their
going to sleep.

Left thus to my own resources, I must be content for the present to bri