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Proceedings of the Royal Society of Edinburgh. [Sess. 
(2) By causing a dilatation of the cutaneous blood-vessels and an 
increased loss of heat, thus leading to a lowering of the temperature. 
(3) preventing the nervous system from acting upon the muscles, i.e. 
by paralysing the muscular system and thus checking the liberation of heat 
in the body. 
Against the third hypothesis may be set the fact, which Harnack (6) 
and Marshall (7) have so clearly demonstrated, that various convulsants 
which cause powerful muscular contractions do not raise the temperature 
of the animal. 
In order to test the second hypothesis several experiments were carried 
out in which the animal, during the period of experiment, was well wrapped 
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up in cotton- wool. With ether alone under these conditions the fall of 
temperature did not take place (see Chart VII.), and in the case of the drug 
plus ether and cotton-wool there was likewise no fall, indeed the rise of 
temperature continued (see Chart VIII.). 
These last experiments point very directly to the fact that the fall of 
temperature due to the anaesthetic is to a large extent the result of heat 
loss by vaso-dilatation. The observation that the ears of the animals were 
