204 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 
transported in air-tight sterilised paint tins, and on arrival 
at the laboratory the tins were packed round with ice. 
In no case was an interval of more than 20 hours allowed 
to elapse between the times of collection and incubation. 
Ten cockles were selected at random from the sample 
and washed under the tap. They were opened by 
sterilised knives so that the “ fish ’’ remained in one valve. 
then, by means of sterile scissors, the soft parts of the 
mollusc were cut into as small pieces as possible, while 
still lying in the sheil, the latter being held over a small 
sterile glass mortar. In this way all the bodies of ten 
cockles were cut up and put into the mortar. It is 
necessary to take some pains thoroughly to clean and 
sterilise the fingers, since the latter are almost sure to 
receive some of the liquid dripping from the shell into the 
mortar. ‘The soft pulp in the latter is then thoroughly 
beaten up with the pestle until an emulsion of the soft 
bodies, with the liquor in the shells, is formed. Unless 
a homogeneous emulsion is prepared irregular results are 
obtained. 
This emulsion is then poured into a flask and diluted 
to 100 c.c. with sterile water, and the whole is very 
thoroughly mixed. But it is impossible to obtain a 
uniform suspension in water of the soft parts of the 
molluses. Therefore the flask is allowed to stand for a 
few minutes until the heavier parts of the solid matter 
have. settled to the bottom. Probably the bacteria 
inhabiting the cockle aie pretty evenly distributed 
through the quid; but, at any rate, this must be 
assumed, for it is only the liquid, containing the finer 
particles in suspension, that can be examined. Ten c.c. 
of the liquid are then taken and added to 90 c.c. of sterile 
water in a second flask, and again 10 ¢.c. of the thoroughly 
mixed liquid in this second flask are added to 90 c.c of 
