mysterious than the fact that agents which, as sedatives or excitants,
affect the great nerve-centres, do this very differently in different
climates. There is some evidence to show that this is also the case with
narcotics; and perhaps a partial explanation may be found in the manner
in which the excretions are controlled by external temperatures, as well
as by the fact which Dr. Brown-Séquard discovered, and which I have
frequently corroborated, that many poisons are retarded in their action
by placing the animal affected in a warm atmosphere.

It is possible to drink with safety in England quantities of wine which
here would be disagreeable in their first effect and perilous in their
ultimate results. The Cuban who takes coffee enormously at home, and
smokes endlessly, can do here neither the one nor the other to the same
degree. And so also the amount of excitation from work which the brain
will bear varies exceedingly with variations of climatic influences.

We are all of us familiar with the fact that physical work is more or
less exhausting in different climates, and as I am dealing, or about to
deal, with the work of business men, which involves a certain share of
corporal exertion, as well as with that of mere scholars, I must ask
leave to digress, in order to show that in this part of the country at
least the work of the body probably occasions more strain than in
Europe, and is followed by greater sense of fatigue.

The question is certainly a large one, and should include a
consideration of matters connected with food and stimulants, on which I
can but touch. I have carefully questioned a number of master-mechanics
who employ both foreigners and native Americans, and I am assured that
the British workman finds labor more trying here than at home; while
perhaps the eight-hour movement may be looked upon as an instinctive