XVI.—A Partial Analysis ofDrosophilaLarval Hæmolymph

Synopsis Physical and chemical methods of analysis suitable for volumes ofDrosophilahæmolymph under I μl. are described. The osmotic pressure of hæmolymph is equivalent to 1·05 per cent NaCl. The pH is 6·6·6·7. Na+, K+, Ca2+, Mg2+, Cl−and PO3−4occur in concentrations of 56·5, 40·2, 8, 20·8, 42·2 and 2·8 mM/1. Probably the only sugar present is trehalose. A rough analysis for amino-acids indicates that they contribute an amount to the osmotic pressure equivalent to about 0·4 per cent NaCl. These results are discussed in relation to tissue culture.