182
ANTON F. BRUUN
sea water. Nor did Koch find any sign of demineralization in the
female silver eel, when leaving fresh water and freshly caught.
Fontaine and Callamand, in fact, reviewed the problem about
&mineralization on the female silver eel in a paper (1948, p. 318) of
which it is sufficient to cite their comparison of new experiments with
earlier oms : “ Toutefois l’intensitk de la d6minhralisation du milieu
inthrieur nous Btait apparue, sup ces shies, en liaison directe avec
dhveloppement ponddral des ovaires. Ce n’est cependant pas l& une
rhgle gdn8raIe. En effet, au cours de I’hiver 1947-48, nous avons r e p du
lac de Grand Lieu des Anguilles jaunes et des Anguilles argent6es Bans
qu’apparaissent des diffhences significatives entre les unes et les
autres. Les chlorBmies Btaien; assez variables, comprises entre 4 et 7
grammes x0 (Toutes les valeurs sont exprimees en NaCl %, ), mais
les valeurs obtenues sur leu Anguilles jaunes et les Anguilles argentdes
6taient Btroitement m&16es. Ainsi, l’hypochlorbmie n’est pas une
caracthistique biochimique obligatoirement like Q. l’argenture de
1’Anguille et A sa transformation en Anguille argentke.”
Again, if Tucker had cited only just the last sentence, all his arguments about this probIem would have given his readers a more correct
impression about the facts.
Fontaine and Koch (1950, p. 302) also explain the findings of
Callamand and Fontaine (1940) and Callamand (1943). Fontaine and
Koch also found a demineralization, when female silver eels are kept
in fresh water without food for 4 to 5 months. But, as they point out,
this is the situation first observed by Fontaine and Callamand, a
consequence of two factors working towards the same result :
1. The absence of alimentary contribution of mineral matter
2. The non-existence in the eel of an extra-enteral mechanism for
because of the starvation.
the absorption of mineral ions (Krogh, 1937).
Tucker (1959b, p. 1406) findsimportant support from Schnakenbeck’s
(1934) and Berndt’s (1938) descriptions of autolysis and phagocytosis
of the gut. The fact is, however, that nobody has ever found a high
mortality of silver eels which could be ascribed to malfunction of the
gut as an osmo-regulatory mechanism in salt water.
As Tucker (1959a, p. 497) points out, mass-mortalities of eels have
been observed; but instead of mentioning a case from 1655 (Nicoll,
1836, 2, p. 234,JLide Tucker) and 1914 (Mazzarelli, 1914) it seems to me
that some of the many later cases where the cause was examined should
have been included. ’ In 1655 very little was known about the biology
of the eel, but we now know that cold winters may kill immense num-
ANTON F. BRUUN
sea water. Nor did Koch find any sign of demineralization in the
female silver eel, when leaving fresh water and freshly caught.
Fontaine and Callamand, in fact, reviewed the problem about
&mineralization on the female silver eel in a paper (1948, p. 318) of
which it is sufficient to cite their comparison of new experiments with
earlier oms : “ Toutefois l’intensitk de la d6minhralisation du milieu
inthrieur nous Btait apparue, sup ces shies, en liaison directe avec
dhveloppement ponddral des ovaires. Ce n’est cependant pas l& une
rhgle gdn8raIe. En effet, au cours de I’hiver 1947-48, nous avons r e p du
lac de Grand Lieu des Anguilles jaunes et des Anguilles argent6es Bans
qu’apparaissent des diffhences significatives entre les unes et les
autres. Les chlorBmies Btaien; assez variables, comprises entre 4 et 7
grammes x0 (Toutes les valeurs sont exprimees en NaCl %, ), mais
les valeurs obtenues sur leu Anguilles jaunes et les Anguilles argentdes
6taient Btroitement m&16es. Ainsi, l’hypochlorbmie n’est pas une
caracthistique biochimique obligatoirement like Q. l’argenture de
1’Anguille et A sa transformation en Anguille argentke.”
Again, if Tucker had cited only just the last sentence, all his arguments about this probIem would have given his readers a more correct
impression about the facts.
Fontaine and Koch (1950, p. 302) also explain the findings of
Callamand and Fontaine (1940) and Callamand (1943). Fontaine and
Koch also found a demineralization, when female silver eels are kept
in fresh water without food for 4 to 5 months. But, as they point out,
this is the situation first observed by Fontaine and Callamand, a
consequence of two factors working towards the same result :
1. The absence of alimentary contribution of mineral matter
2. The non-existence in the eel of an extra-enteral mechanism for
because of the starvation.
the absorption of mineral ions (Krogh, 1937).
Tucker (1959b, p. 1406) findsimportant support from Schnakenbeck’s
(1934) and Berndt’s (1938) descriptions of autolysis and phagocytosis
of the gut. The fact is, however, that nobody has ever found a high
mortality of silver eels which could be ascribed to malfunction of the
gut as an osmo-regulatory mechanism in salt water.
As Tucker (1959a, p. 497) points out, mass-mortalities of eels have
been observed; but instead of mentioning a case from 1655 (Nicoll,
1836, 2, p. 234,JLide Tucker) and 1914 (Mazzarelli, 1914) it seems to me
that some of the many later cases where the cause was examined should
have been included. ’ In 1655 very little was known about the biology
of the eel, but we now know that cold winters may kill immense num-