LABORATORY METHODS 219 



product from which methylated spirit is made, but without the addition of any methyl- 

 ating substances. In strength it varied from 94 to 95 per cent, and it was carried in 

 10 gallon drums. These drums gave a considerable amount of trouble, for in less than 

 a year many of them rusted on the inside and the spirit became turbid with fine rust 

 in suspension. At sea there was no opportunity for the rust to settle and for a time it 

 was necessary to filter all supplies. Later, a galvanized tank was supplied to the 'Dis- 

 covery' and filled with clear spirit whenever the ship was in port. 



The Formalin was neutralized, as recommended by Atkins,^ by the addition of 

 5 grm. of borax to every litre of undiluted solution. Experience showed that special 

 care must be taken of formalin in the Antarctic. During the first season it was dis- 

 covered that a large proportion of the formalin which had been stowed in carboys on 

 the boat-skids of the ' Discovery' had become converted into paraformaldehyde, forming 

 a white insoluble precipitate which cannot apparently be reconverted into its original 

 form. It became necessary to filter the supplies, and with some carboys almost half 

 the quantity was lost in the process. The same thing occurred with formalin which 

 had been left in cases out-of-doors at the Marine Station, South Georgia. So far as 

 can be ascertained the difficulty is due to low temperatures, for formalin kept in the 

 ship's hold, or indoors at the Marine Station, did not deteriorate. 



Storage of Specimens. All smaller organisms were preserved in tubes or bottles. 

 Flat-bottomed tubes of all sizes from i x j in. to 6^ x i| in. were used and these 

 tubes, when filled, were plugged with a ball of cotton-wool wrapped up in tissue paper 

 and stored in bottles. The reason for wrapping the wool plug in tissue paper is that 

 certain organisms entangle themselves in wool and cannot afterwards be freed from it 

 without damage. This method is to be preferred to corks, which sometimes cause 

 discoloration of specimens and are liable to shrink and allow the contents to dry up. 

 If wool is placed at the bottom and top of the bottles in which the tubes are stored, 

 the danger of breakage is very slight. These tubes were used for bulk plankton as well 

 as for isolated specimens, but they are better adapted to the latter than the former. 

 Plankton might more conveniently be stored in h lb. screw top bottles, a method which 

 would save a great deal of the labour involved in reducing samples to a small volume. 

 Copper funnels with short and wide necks were found most useful in the reduction 

 of plankton samples. Those used were 6 in. and 4 in. in diameter of mouth and ih in. 

 and f in. respectively in diameter of neck. After the bulk of the fluid had been filtered 

 off through fine silk the remainder of the sample was poured into a tube or jar through 

 one or other of the funnels. 



Extra long tubes, ih in. in diameter and 12, 18 and 24 in. in length, were taken for 

 the preservation of long and slender animals, and for these corks had to be used. These 

 tubes were sealed by dipping the ends in melted wax, and they were specially packed 



1 Atkins, Jo«;7/. Marine Biol. Assoc, n.s., xn, pp. 792-4, 1922. 



