310 
THE FAMILY OF EELS. 
This illustrious physiologist remarks further, that the presence 
of life allowed the vital heat to be lowered to two or three 
degrees below the freezing point; but after this it resisted all 
further decrease; and when the powers of bfe had become 
expended by the exertion of thus resisting decrease, the creature 
became frozen like any other dead matter. 
An Eel in a weak condition was found to have the heat of 
its stomach at 44'^, which was at the same time the temperature 
of the air. It was then put into water heated to 65°, and 
kept there for fifteen minutes; in which time the fish had 
acquired the same heat as the water; and it M'as noticed that 
a living and a dead Eel received an equal amount of heat and 
cold in an equal length of time; and he appears to think that 
if the M'hole body of a fish should become really frozen, it 
would have become past recovery by thawing. As a frog was 
found to be able to digest its food when the heat was at 60°, 
but to have lost that power when it was below 40°, the same 
appeared to be the case with the Eel; which circumstance vv’ill 
explain what has been observed of this fish in captivity; and 
in a short scries of observations on the upward migration of 
young Eels, we have noticed that they do not shew themselves 
while the temperature of the stream is below the annual medium 
temperature of the air. 
There is no need that our attention should be engaged in 
giving an account of the surmises which were hazarded on 
the subject of the productive organs of these fish, the error 
of which was caused by the expectation of finding in their 
bodies a close resemblance of the milt and roe of most othel 
fishes, to which, however, their organs of propagation bear in 
some particulars but a distant likeness. But their situation in 
the body is the same, and both the milt and roe lie along 
the couise of the back in a double, thin, and convoluted 
stripe, which bears the appearance of fiit rather than an organ 
embedding grains of seed, which are in reality enveloped in 
an oily substance, the use of which appears to be to afford 
protection against changes of temperature that might be hurtful 
to the spawn before it is shed. That the small grains embedded 
within this soft and greasy covering are truly the spawn of 
the fish is proved by the examination I have been able to 
make, as also by the inquiries of other observers. Thus a 
