D. Bellamy

WATER AND ELECTROLYTE COMPOSITION OF THE BODY AND RENAL FUNCTION OF THE EEL (ANGUILLA ANGUILLA L.).

Abstract 1. 1. The water, sodium, potassium and chloride contents of serum and muscle of yellow and silver eels (Anguilla anguilla L.) in fresh water and sea water are given, together with urine output and glomerular filtration rates. ∗ . Ion concentrations m-moles/kg tissue H2O Type of eel Freshwater Seawater Na+ K+ Cl− Na+ K+ Cl− Serum ∗ 155 2·7 106 178 2·8 155 Parietal muscle 30·4 110·1 35·0 124·7 “Tongue” muscle 41·9 112·6 47·9 121·7 Urine ∗ 18·9 0·65 Nil 6·5 2·08 119·4 2. 2. The results are discussed in relationship to the general problem of the adaptation of vertebrates to water of differing tonicity.

Adaptation of the silver eel (Anguilla anguilla L.) to sea water and to artificial media together with observations on the role of the gut

Abstract 1. 1. Silver eels were transfered to a sucrose solution having the same osmotic pressure as sea water. Death occurred within 24 hr with considerable weight loss and wrinkling of the skin. Weight loss was not due to the absence of drinking. The addition of calcium and sodium in the ratios of 1 : 10 and 1 : 20 prolonged life for up to 6 days. 2. 2. Isolated gut sacs containing sea water were incubated in a Krebss saline medium at 25°C. After 2 hr there had been a passive influx of water from the incubation medium and from the gut wall tissue into the gut sac, representing an increase in volume of 18–46 per cent. 3. 3. The rate of passive water movements through preparations of posterior intestine was greater in seawater-adapted eels than in eels from fresh water. 4. 4. There was a passive efflux of sodium along a diffusion gradient, of 16–35 per cent in 2 hr, and sodium loss was greatest in the anterior intestine of freshwater eels.

Studies on Myxine glutinosa. I. The chemical composition of the tissues.

1. (1) Determinations were made of the concentrations of the major low molecular weight constituents in serum, muscle and liver of Myxine glutinosa L. (the Atlantic hagfish). 2. (2) The intracellular concentrations of the above substances have been calculated using the inulin space as a measure of the extra-cellular fluid compartment of the tissues. 3. (3) The concentrations of potassium, sodium and chloride in the intracellular water were 140–200, 110–150 and 100–120 mM/kg respectively. For potassium the ratio of the intracellular to extracellular concentration was 12 : 1. The corresponding ratio for sodium was 1 : 4·5. 4. (4) From the composition of the various tissues it is likely that serum and cells had the same osmotic pressure as sea water. Serum contained mainly inorganic ions and the intracellular fluid contained approximately equal quantities of inorganic and organic constituents. 5. (5) The major intracellular organic compounds were amino acids (20–70 mM/kg H2O), trimethylamine oxide (211–230 mM/kg H2O) and an unknown acidic substance about 200 mM/kg H2O).

An apparatus for studying the gain and loss of electrolytes by the eel.

Abstract The apparatus is being used to investigate the effects of hormones on water and electrolyte movements in yellow and silver eels adapted to fresh water and sea water.