22.6 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 
all the rest—23 out of 25-—were polluted to a remarkable 
extent, It should be noted, also, that only m this 
original, untreated, sample did the significant white 
colonies occur. 
The fact that a small proportion of the mussels dealt 
with did not cleanse themselves to an appreciable extent 
is to be attributed to the defects of the experiment. The 
latter was carried out rather roughly. If, instead of 
laying down the shell-fish on the beach, they had been 
placed in large tanks, so as to ensure an effective circula- 
tion of water, the results would have been better. 
As already stated, all the conclusions stated here have 
already been made by Klein in his experiments made for 
the Fishmongers’ Company, and we have only attempted 
to verify the results of those experiments (which were 
made under laboratory conditions) in the case of 
experiments conducted in the open. It is clear that a 
considerable degree of cleansing follows when badly 
polluted mussels are relaid in such a situation where they 
receive only the unpolluted water of the flood tide stream ; 
and that a period of four days is a long enough quarantine 
period. After four days httle or no further cleansing 
takes place. The recommendation is obvious: Mussels 
taken from such highly suspicious grounds as those in the 
Channel from the Conway Bridges down to below 
Deganwy Sewer outfall ought to be relaid high up on the 
Morfa Beach, where the only water that reaches them is 
that of the flood-tide or the first portion of the ebb-tide, 
and kept there for at least four days. The precise 
arrangement and construction of the receptacles—tanks, 
ponds, cages, &c¢.—for containing these mussels is a 
matter of some little experiment: no apparent difficulty 
suggests itself. The expenses might be relatively great, 
but compared with the capital value represented by the 
