4. ANALYSIS O F FACTORS INVOLVED I N SYMBIOSIS
61
Bruyne (1 893, 1895) who also investigated phagocytic activity by
molluscan leucocytes. Cuenot (1914), in connection with his report on
phagocytosis in molluscs, particularly the amphineuran Acanthochites
discrepeus, reported that ink particles introduced into the blood-stream
are removed via phagocytic activity of blood cells. His primary concern, however, was with the immediate removal of the ink particles
rather than with their ultimate disposal. Other investigators (Vonk,
1924; Yonge, 1926; Takatsuki, 1934; Nelson, 1933) have described the
role of leucocytes in the digestive functions of various species of
oysters.
Modern experiments on the role of molluscan amoebocytes began
with Stauber (1950) who experimentally injected India ink intracardially into Crassostrea virginica and traced the fate of the ink
particles. He found that, starting as soon as 15 min after injection, the
ink suspensions will agglomerate and produce emboli which virtually
occlude the arterial vessels of the viscera, mantle and adductor muscle.
Subsequently, the ink particles are phagocytized by mobile phagocytes
and are distributed to all parts of the oyster with concomitant resolution of the emboli. Eventually, around the 8th day after injection,
the ink particles are eliminated from the mollusc by the migration of
ink-laden phagocytes through the epithelial layers of the alimentary
tract, digestive diverticula, palps, mantle and pericardium from whence
the.y are voided to the exterior. It is of interest to note that the epithelia
of the gonaducts, nephridia, and shell-forming mantle were not found
to be routes of elimination. Subsequent studies by Tripp (1958a,b, 1960),
who experimentally injected normal erythrocytes of the rabbit, weakfish, duck, duck erythrocytes infected with the avian malaria parasite
Plasmodium lophurae, bacterial spores, vegetative bacteria, and yeast
cells into Crassostrea virginica, showed essentially the same pattern of
phagocytic activity. However, Tripp, as the result of employing a
greater variety of foreign particles, has been able to show that digestible
particles (erythrocytes, vegetative bacteria, some yeast cells) are
eliminated via the migration of particle-laden phagocytes across
epithelial barriers as well as being digested intracellularly in phagocytes.
Non-digestible particles (malarial pigments, most yeast cells, bacterial
spores) are eliminated almost completely by migration of phagocytes
across epithelial barriers. He also has demonstrated that the plasma
(hemolymph) of the oyster is bactericidal. Another of Stauber’s
students, Feng (1959, 1965a), also worked on this problem. He has
found that soluble starch, bovine hemoglobin, human serum albumin,
diphtheria antitoxin, and rhodamine-labelled proteins, all nonparticulate materials, will become pinocytized and are either digested
61
Bruyne (1 893, 1895) who also investigated phagocytic activity by
molluscan leucocytes. Cuenot (1914), in connection with his report on
phagocytosis in molluscs, particularly the amphineuran Acanthochites
discrepeus, reported that ink particles introduced into the blood-stream
are removed via phagocytic activity of blood cells. His primary concern, however, was with the immediate removal of the ink particles
rather than with their ultimate disposal. Other investigators (Vonk,
1924; Yonge, 1926; Takatsuki, 1934; Nelson, 1933) have described the
role of leucocytes in the digestive functions of various species of
oysters.
Modern experiments on the role of molluscan amoebocytes began
with Stauber (1950) who experimentally injected India ink intracardially into Crassostrea virginica and traced the fate of the ink
particles. He found that, starting as soon as 15 min after injection, the
ink suspensions will agglomerate and produce emboli which virtually
occlude the arterial vessels of the viscera, mantle and adductor muscle.
Subsequently, the ink particles are phagocytized by mobile phagocytes
and are distributed to all parts of the oyster with concomitant resolution of the emboli. Eventually, around the 8th day after injection,
the ink particles are eliminated from the mollusc by the migration of
ink-laden phagocytes through the epithelial layers of the alimentary
tract, digestive diverticula, palps, mantle and pericardium from whence
the.y are voided to the exterior. It is of interest to note that the epithelia
of the gonaducts, nephridia, and shell-forming mantle were not found
to be routes of elimination. Subsequent studies by Tripp (1958a,b, 1960),
who experimentally injected normal erythrocytes of the rabbit, weakfish, duck, duck erythrocytes infected with the avian malaria parasite
Plasmodium lophurae, bacterial spores, vegetative bacteria, and yeast
cells into Crassostrea virginica, showed essentially the same pattern of
phagocytic activity. However, Tripp, as the result of employing a
greater variety of foreign particles, has been able to show that digestible
particles (erythrocytes, vegetative bacteria, some yeast cells) are
eliminated via the migration of particle-laden phagocytes across
epithelial barriers as well as being digested intracellularly in phagocytes.
Non-digestible particles (malarial pigments, most yeast cells, bacterial
spores) are eliminated almost completely by migration of phagocytes
across epithelial barriers. He also has demonstrated that the plasma
(hemolymph) of the oyster is bactericidal. Another of Stauber’s
students, Feng (1959, 1965a), also worked on this problem. He has
found that soluble starch, bovine hemoglobin, human serum albumin,
diphtheria antitoxin, and rhodamine-labelled proteins, all nonparticulate materials, will become pinocytized and are either digested