PHYSIOLOGY OF LAMELLIBEANCH BLOOD-COEPUSCLES. 619 
could usually be seen to enter the tube, and there was an 
apparent concentration of the corpuscles about the mouth of 
the tube after the lapse of from half an hour to an hour, but 
though negative results were given in check experiments, in 
which capillary tubes filled with sea-water were employed, yet 
the number of corpuscles were usually so few (four to eight 
on an average in half an hour), that the results cannot be con- 
sidered conclusive. Much more conclusive results were given 
by introducing similar capillary tubes into the anterior 
adductor muscle, and leaving them there about two hours, 
having inserted a small wedge between the valves of the shell 
to prevent the breaking of the tubes. Tubes filled with the 
following- fluids were employed, and all introduced at the same 
time into the same animal : 
(1) Culture of non-motile bacilli in peptonised fish-broth 
made with sea-water. 
(2) Peptonised fish-broth made with sea-water. 
(3j Culture of the same bacilli in the blood of Cardium 
norvegicum. 
(4) Filtered extract of the tissues of Cardium nor- 
vegicum which had been killed by heat and then minced in 
sea-water. 
(5) The fresh blood of Cardium norvegicum. 
(6) Sea-water. 
It was assumed that a positive result was given when over 
twenty corpuscles were seen free in the tube, and a mass of 
agglutinated corpuscles was found at the mouth of the tube 
and extending a little way up it. On this assumption, jjositive 
results were given with the culture in broth (1), the culture 
in blood (3), and the extract of the tissues (4), and negative 
results with the fresh blood (5), and sea- water (6). Varying 
and inconclusive results were given with the sterile fish- 
broth (2). These conclusions represent the mean of a large 
number of experiments. The chief experimental errors, which 
are liable to cause false results, are due to employing capillary 
tubes which are rough at the open end ; in this case the 
opening becomes rapidly closed by a mass of agglutinated 
