SEA- FISHERIES LABORATORY. 153 



shaking to get rid of any sea-water, the posterior adductor, 

 or large muscle, was cut, and the flesh scraped into a weighed 

 1,000 c.c. flask, through a glass funnel. While passing slowly 

 through the funnel the mussels were minced up with the blade 

 of a scalpel. The wet weight of this mass was found to be 

 337-9 grammes. Two hundred and thirty- two c.c. of 60 % 

 caustic potash was introduced into the flask, a reflux condenser 

 fitted, and the whole heated on a water bath for three hours. 

 At the end of this time the tissue was broken down in a most 

 thorough manner. After cooling, the contents of the 1,000 c.c. 

 flask was transferred to a tall measuring glass and touched the 

 560 c.c. mark. The mixture was then diluted with water 

 until the total amount of liquid and tissue came to 1,400 c.c. 

 After stirring well with a glass rod, the mouth of the measuring 

 glass was covered with a petrie dish and the sediment left to 

 settle. This took place in about twenty-four hours, the residue 

 at the bottom measuring up to 170 c.c. 



A siphon tube was then placed under the soapy film which 

 had formed on the surface of the liquid, and the clear part of 

 the latter siphoned off from above the sediment into a tall, 

 glass vessel capable of holding 3,000 c.c. This method of 

 siphoning, while allowing a small quantity of glycogen to 

 remain behind in the measuring glass, saves a good deal of 

 trouble in the subsequent filterings. 



The glycogen was precipitated from the liquid thus 

 obtained by adding twice its volume of 95 % alcohol. The 

 precipitate was allowed to settle and the liquid then decanted 

 off through a filter paper, contained in a glass funnel, and 

 fitted with a supporting metal cone. The filtration was 

 hastened by the use of a filter pump. The glycogen was then 

 washed by shaking with a little fresh alcohol and run on to 

 the same filter paper. To cleanse the glycogen more thoroughly, 

 it was dissolved by running boiling water through the paper, 

 and the opalescent liquid thus formed received into a fresh 



