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'XII. On the irifluence of nerves and ganglions in producing animal 
heat. By Sir Everard Home, Bart. V. P. R. S. presented 
by the Society for the Improvement of Animal Chemistry. 
Read March 17, 1825. 
X N considering this subject, I shall first mention that in the 
most simple animal structures endowed with life, large 
enough to admit of dissection, brain and nerves are met 
with, although many such animals possess no power of pre-^ 
serving a temperature higher than that of the atmosphere 
by which they are immediately surrounded. 
In the oyster and fresh water muscle the whole nervous 
system consists of two small rounded bodies ; of these one is 
placed upon the oesophagus, one at the opposite end of the 
body of the animal ; they are connected together by two lateral 
nerves, one on each side. 
The internal structure of both these rounded bodies is the 
same, and resembles that of the brain in other animals, 
which I have already shown to be composed of small glo- 
bules, surrounded by a transparent elastic gelatinous liquid : 
having this structure I shall consider them to represent 
the brain and the spinal marrow of the animal. 
The temperature of the oyster does not exceed that of the 
surrounding water, since a small thermometer introduced 
between the shells when kept open by a wedge undergoes 
no change. 
