were adduced in support of a theory I entertained as to the
re-invigoration of the human system by principles similar to those which
Liebig has applied to the replenishment of an exhausted soil,--namely, the
giving back to the frame those essentials to its nutrition, which it has
lost by the action or accident of time; or supplying that special pabulum
or energy in which the individual organism is constitutionally deficient;
and neutralizing or counterbalancing that in which it super-abounds,--a
theory upon which some eminent physicians have more recently improved with
signal success. But on these essays, slight and suggestive, rather than
dogmatic, I set no value. I had been for the last two years engaged on a
work of much wider range, endeared to me by a far bolder ambition,--a work
upon which I fondly hoped to found an enduring reputation as a severe and
original physiologist. It was an Inquiry into Organic Life, similar in
comprehensiveness of survey to that by which the illustrious Muller, of
Berlin, has enriched the science of our age; however inferior, alas! to
that august combination of thought and learning in the judgment which
checks presumption, and the genius which adorns speculation. But at that
day I was carried away by the ardour of composition, and I admired my
performance because I loved my labour. This work had been entirely laid
aside for the last agitated month; now that Lilian was gone, I resumed it
earnestly, as the sole occupation that had power and charm enough to rouse
me from the aching sense of void and loss.

The very night of the day she went, I reopened my manuscript. I had left
off at the commencement of a chapter Upon Knowledge as derived from our
Senses. As my convictions on this head were founded on the well-known
arguments of Locke and Condillac against innate ideas, and on the
reasonings by which Hume has resolved the combination of sensations into a
general idea to an impulse arising merely out of habit, so I set myself to
oppose, as a dangerous concession to the sentimentalities or mysticism of