606 
G. H. DREW. 
corpuscles, the great vitality of the animal, and its large and 
readily protruded foot. 
One object of the present work was to investigate the 
“ clotting ” of Lamellibrauch blood-corpuscles, and to follow 
the relation this process bears to the natural cessation of 
haeinorrhage from a wound and its subsequent healing. Another 
object was to investigate the phagocytic action of the cor- 
puscles on bacteria, and to find whether they showed any 
chemiotactic action towards cultures of bacteria or extracts 
of dead tissues. 
My results show that some change takes place in the 
corpuscles when the blood is shed, which causes them to 
agglutinate round the edges of a wound, and that these 
masses of corpuscles are connected by thin protoplasmic pro- 
cesses running across tlie wound. These processes thicken 
and contract, and so draw together the edges of the wound. 
There is some evidence to show that the change in the cor- 
puscles, which makes them agglutinate, is produced by a con- 
tact stimulus imparted on contact with a foreign body or 
with injured tissues. Some of the coi'puscles have a phago- 
cytic action on bacteria, and show a positive chemiotactic 
attraction towards cultures of bacteria and extracts of dead 
tissues, so that their protective function appears to be the 
same as that of the leucocytes of mammalian blood. 
My thanks are due to the Marine Biological Association of 
the United Kingdom for their kindness in granting me a 
table at their Plymouth Laboratory. 
Historical. 
The chemistry of the blood of the Lamellibranchiata has 
been thoroughly investigated by Ray Lankester (9, 10, 11, 
and 12), Cuenot (2), Griffiths (8), and others, but a number of 
observers have described the organised elements of the blood 
with very varying results. Their conclusions are summarised 
by de Bruyne (3). He himself recognises seven varieties of 
corpuscles in Lamellibranch blood, taking as his types 
