

SEA-FISHERIES LABORATORY. 147 



despatched to Liverpool the same way, through the post in 

 tins. They usually arrive in good condition, with the valves 

 of the shells tightly closed. 



Method of dealing with samples. 



The outsides of the mussel-shells are first freed from 

 barnacles and any foreign matter, washed under the tap, and 

 dried with a towel. The mussels are prised open with a pair 

 of forceps, and a small wooden peg placed between the valves 

 to prevent them from reclosing. After shaking to get rid of 

 any water which may be lodged in the mantle cavity, the 

 mussels are reared up in small racks, with the posterior end 

 of the shell resting on a sheet of blotting paper ; the latter 

 absorbs any mucus or excreta that may drain away. It is 

 necessary to open the shells carefully, because if the flesh is 

 punctured, blood and liquid flows from the animal itself. 

 The draining is continued until a dry glaze begins to show on 

 the surface of the flesh, a process which generally takes a little 

 over two hours. 



Six mussels are then chosen at random and placed on 

 one side for special examination. The remaining mussels in 

 the sample, with their shells, are weighed in bulk, and after the 

 soft parts are removed, the shells alone are weighed. The 

 difference, of course, gives the wet weight of the soft parts. 

 In all cases the byssus threads are weighed in with the shells. 

 It is from this latter part of the sample that mussels are obtained 

 for sectioning to show the distribution of fat in the tissue. 



The six mussels taken from the sample are each weighed 

 in their shells separately on a balance. The soft contents are 

 then scraped with care, by means of a scalpel, into a small 

 porcelain dish which has been previously dried and weighed. 



The cleaned shell with any byssus threads are also weighed 

 separately, and it is then possible, by subtracting such weights 

 from those of the mussels with shells, to obtain the wet weight 

 of the flesh in the basin. This gives a more accurate result 

 than weighing the basin and flesh direct, because the removal 



