1896-97.] Mr George Murray on Marine Diatoms. 
209 
however, is a different condition from the one described above, 
though it has an interest in connection with it. 
For several years Dr John Murray has urged me to investigate 
the pelagic Algae, and in March of this year I gratefully accepted 
his invitation to make a study of the marine diatoms on behalf of 
the Fishery Board for Scotland, and my special thanks are due to 
the Board and to Dr Wemyss Fulton, the Superintendent of 
Scientific Investigations, for the facilities freely accorded me for 
the prosecution of this research. I spent a fortnight in March 
and April and three weeks in August on the fishery cruiser 
“ Garland,” engaged in this work principally on the west coast of 
Scotland. The ordinary method of capture by means of fine silk 
tow-nets was employed, hut Dr Murray’s ingenuity furnished me 
with another resource for employment in rough weather, when 
tow-netting is impossible or at least attended with risk to the 
nets; and the conditions of sea climate for part of last March 
and April made me mindful of his foresight. This instrument was 
a fine silk hag, shaped somewhat like a large German sausage, to he 
fastened over the nozzle of the hose used for washing the decks. 
The hag had a small lateral overflow vent about the size of a six- 
pence (which it is well to strengthen with an extra thickness of 
silk and a “ buttonhole stitch ”), and it is useful in rough weather 
or after dark. If the donkey-engine is made to pump through it 
gently for half an hour, under most circumstances a good haul is 
obtained. The nozzle and hag should be fastened to a stanchion 
or boat davit above the level of the bulwark, where it is safe from 
injury by the sea. While describing methods, I may record the 
entire success of the fixing and preservative fluid employed, the 
precise strength of which was exactly forecasted by my colleague, 
Mr Y. H. Blackman. I carried a number of strong tubes half filled 
with0 - 5 per cent, aqueous solution of chromic acid. This is about 
the same density as ordinary sea-water, and I simply added my 
captures in sea-water to it, filling up the tube. If this he done 
with care the cell-contents are fixed and maintain the appearance 
they possessed before death. During the autumn I spoiled several 
tubes by adding too dense a mass of diatoms, displacing the propor- 
tion of sea-water, and it sufficed to ruin the condition of the cell- 
contents in these cases. The process must therefore be carried out 
VOL. XXI. 21/12/96 
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