716 
DE. E. SMITH OX THE ACTIOX 
but since, as has been just mentioned, so great a part of the latter would have occuiTed 
if the food had been withheld, it is impossible to afiirm that it was due to its influence. 
This has afforded me an inquiry of a well-defined nature, and one which my apparatus 
permitted me to make with ease ; and it is one, moreover, so far as I know, not hereto- 
fore pursued. 
Nearly all previous inquiries have been made upon the lower animals, and have had 
for their- object to determine the effect upon nutrition of the exclusive use or the entme 
absence of certain substances, and only a few experiments have been made upon Man. 
Prout* ascertained that the per-centage of carbonic acid in the expired air was some^ 
what lessened under the influence of both tea and alcoholic liquors ; and A lERORUTf 
found the same result from the latter without any apjpredahle difference^ in the other 
phenomena of respiration. BoekerJ has made the most remarkable inqumes mto this 
subject ; and the method adopted by him was to take a considerable quantity of the sub- 
stance, as sugar, for example, at several periods of the day, m addition to his ordinarv' 
food, and afterwards ascertain the state of the excretions and the respiration at several 
irregular periods. When we recollect how great is the variation in the quantity of 
carbonic acid evolved at different periods of the same day, and how m-egulai- is the 
quantity on different days,— how powerful is the effect of exertion, an mfluence which 
cannot under ordinary circumstances be the same on any two days,— the disturbmg 
influence of unusually large or often repeated quantities of a substance, and lastly, the 
unknown influence of other articles of food, varying in quantity and quality,— it is easy 
to see how difficult it would be for M. Boeker to eliminate the noi-mal and true effect 
of the article under inquiry. He found that sugar, coffee, and alcohol lessened the 
respiratory changes, and that in their principles of action they are identical ; but he 
then inquires how it is, if this be so, that they act as antidotes to each other 1 It will 
be shown that my results do not accord with his. Mr. Milxer§, Simgeon to the 
Government Prison at Wakefield, in a paper which he recently read before the British 
Association, states that he had proved by experiment that tea given to the prisoners, 
whether in lieu of, or in addition to their ordinary food, caused them to lose weight at 
an increasing rate, — a fact which supports my results on the action of that substance. 
My experiments have been made chiefly upon myself, set. 39, and upon Mr. Moul, aet. 48 
(a gentleman whose devotion to the inquiry in the interests of science is beyond all 
praise), but in a few instances upon others also. The plan pursued was as follows.— 
A quantity of the substance under inquiry, not greatly different from that ordinai-il) 
taken by mankind, was administered apart from any other food. The experiments weie 
nearly all made from 7 to 9 a.m., before breakfast ; but some were made at 2 p.m., after 
the influence of the breakfast had passed over. All were made in the sitting postui-e, 
and in the absence of all exertion and mental and bodily excitement. Hence we isolated 
the influence of the substance, and made one long series of experiments under precisely 
* Thomson’s ‘ Annals of PMiosopliy.’ t Physiologie des Athmens. 
+ Beitrage zur Heilknnde, &c., 1849. § Sanitary Eeview, 1S5S. 
