t 488 ] 
eight beats in a minute, and probably more, as in the ex-^ 
periment without my fliirt the pulfations were counted 
before I had left the room ; but there is a further cir- 
cumlfance to be taken into conhderation, that the expe- 
riment attended with opprellion on the breath was made 
in the evening after a very plentiful meal, whereas 
the other was made in the forenoon, fome hours after 
a moderate breakfaft. The unufual degree of fa- 
tigue which I felt from the experiment without my fliirt, 
mufl: be aferibed in great meafure to the more violent 
effort which the living powers were obliged to exert, in 
order to preferve the due human temperature, when fuch 
hot air came into immediate conta6l ivith my body. In 
the prefent cafe it appears beyond all doubt, that the liv- 
ing powers were very much aflifled by the perfpiration, 
that cooling evaporation which is a further provifion of 
nature for enabling animals to fupport great heats. Had 
we been provided with a proper balance, it would un- 
doubtedly have rendered the experiment more complete 
to have taken the exadf weight of my body at going into, 
and coming out of, the room ; as from the quantity loft 
fome eftimate might be formed of the fliare which the 
perfpiration had in keeping the body cool; probably its- 
effedt was very conflderable, but by no means fufiicient 
to account for the whole of the cooling, and certainly not 
equable enough to keep the temperature of the: body to 
fuch an exadl pitch : For it fhould here'be remarked, that 
during all the experiments made this day, whenever I 
tried the heat of my body, the thermometer always came- 
3 veiy 
