E. K. Hanson. 
338 
sand and salt water, with tap water. Only very slight loss of 
pigment occurred in this process. The wrung out weed was then 
placed in large bottles (about 5 litres capacity) and the bottles were 
filled with distilled water with a few drops of chloroform, securely 
corked, and placed in a warm spot. In a few hours’ time the red 
colour began to pass out of the cells into the water, and in a couple 
of days’ time, practically all the phycoerythrin had been extracted. 
The solution so obtained was filtered through glass wool, and the 
filtrate was used for the optical experiments and for those with 
digestive ferments. It possessed a rose colour with a strong orange 
fluorescence. It putrifies rather quickly unless some powerful 
antiseptic is present, but, if kept sterile, it is more resistant both to 
light and air than previous investigators have recorded. Various 
antiseptics were tried, including phenol, thymol, chloroform, carbon 
tetrachloride, and eucalyptus oil; the last mentioned proved by far 
the most effective : metallic salts, e.g., mercuric chloride, are not 
available, as they produce an effect on the colouring matter. 
For the solid material, the simple extract was concentrated to 
about one-third its original bulk by distilling under a pressure of a 
few cms., the temperature not rising over 38°C. Usually in this 
process a little brown-red precipitate was formed, but the solution 
retained its rose colour and orange fluorescence. Any precipitate 
was filtered off, and methylated spirit was then added until the 
fluorescence disappeared, the solution was allowed to stand, and 
the precipitate was filtered off. More alcohol was added to the 
filtrate until most of the red colour had gone, and this fraction 
(much the largest) was allowed to settle, the supernatant liquid 
poured off, and the residue washed several times by decantation 
with 70% spirit, and then transferred in the pasty state to a large 
clock glass and dried in a vacuum dessicator over sulphuric acid. 
This process was adopted partly on account of the extreme 
tediousness of ordinary filtration, and partly because the precipitate, 
being of a gluey nature, was found to stick to the filter paper, 
involving either a heavy loss or contamination with filter paper 
fibre. 
An attempt was made to obtain purer phycoerythrin by drying 
the washed weed in a calcium chloride oven at the ordinary 
temperature; the dried weed was then powdered and extracted with 
various solvents. But it was again found that only water took up 
any phycoerythrin, and even water dissolved the phycoerythrin from 
the dried weed very slowly, and only very dilute solutions could be 
obtained : the method was, therefore, abandoned. 
