Abstract
The blood of Lophius piscatorius is poor in haemoglobin, the volume of red cells being only 17%. The plasma contains less than 40 g. of protein/1., of which only 6 7 % is albumin. This explains its low osmotic pressure. As is well known, it contains more crystalloids than mammalian blood, A(depression of freezing-point) being 0–84°, the same figure being found at Naples, Woods Hole and Plymouth. This rather high concentration is not due to organic constituents, that of total non-protein nitrogen being of the same magnitude as in mammals; it is mainly due to a high content of sodium chloride. Chloride is at a concentration of 15.3 m.equiv./1oo ml., sodium at 18.5, while in mammals they reach 9 and 15 respectively.Total non-protein nitrogen concentrations in plasma are similar to concentrations in mammals; themain non-protein nitrogen constituents of plasma are neither urea, ammonia, uric acid or allantoin, but trimethylamine or trimethylamineoxide. Of our analysis 37% of non-protein nitrogen of plasma remain unidentified, so far as we can rely upon our chemical methods. The power of concentration of the kidney for non-protein nitrogen on the whole is not high; it varies up to fifteen times. But the degree of concentration by the kidney, small for most constituents, even for trimethylamine, seems to be very high for creatine which is the main representative of non-protein nitrogen. Of our urine analysis, 30% of non-protein nitrogen remain as yet unidentified.