152 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



Unfortunately, direct method of estimation of glycogen, 

 such as Pfluger's well-known short method, or Fraenkel's 

 extraction with trichloracetic acid, are hardly applicable in 

 this case. Results thus obtained would be untrustworthy, 

 because the mussels have to travel under adverse conditions 

 for twelve hours or more, and probably during this period 

 some of the glycogen is converted into glucose by enzyme action. 

 Mussels required for sectioning and staining for glycogen have 

 been obtamed by having them placed into absolute alcohol 

 immediately upon gathering from the beds, but this system 

 could not be extended very well to the estimation of amounts 

 of glycogen, because the original weight of the flesh treated 

 would not be known. Inverting the whole of the glycogen 

 into glucose by keeping mussels several days in chloroform 

 vapour, and estimating the glucose by reduction of Fehling's 

 solution has also been tried. It is dangerous, however, to 

 adopt any method which has not been thoroughly tested, and 

 to do this one requires to work near the mussel-beds and thus 

 obtain fresh material. Since circumstances up to the present 

 have not allowed of such a procedure, the carbohydrates in 

 the meantime have been given as the difference on the other 

 percentages. 



One point of interest which arose from the above work 

 is the small amount of trouble with which comparatively large 

 quantities of glycogen may be got from mussels, and it is 

 suggested as an easy and profitable source for obtaining the 

 substance for use in laboratories. The following experiment 

 is given in some detail to show the manner in which mussels 

 were dealt with for this purpose. 



A number of mussels in poor condition, and therefore 

 likely to give minimal returns, were procured from the Wallasey 

 beds hi the River Mersey on January 25th, 1921. 



Thirty-three of the mussels were dealt with an hour or 

 two after gathering. The shells were wedged open, and after 



