G. Brown (George Brown) Goode.

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forms <>f bell animalcules, the swarmers of which would become available as foo<l I'm the Oysters

lying in tin- vk'itiity.

"The iliatonis did not seem to mo. to be more abundant in the headwaters than in t he open creek.
Thru \\a> inn- moss animal of remarkable character, which I found in the headwaters only. This
creature was \M\ abundant, and no doubt its embryos, like those of the infusoria referred to, were
a\ ailable as food.

"Of free-swimming infusoriaus, I noticed a number of genera; one especially attracted my
at tent ion I nun its snake like appearance and singularly rapid contortions; it had a tuft of vibrating
hairs or eilia at the head end in close relation with the mouth. Another more abundant \y\te was
the em ions genus Huplotex, with a thick shell inclosing the soft protoplasm of the body; the latter
was of an oval form, flat beneath and rounded on the back, so that the resemblance when the
hir-r toot like cilia were in motion, carrying the animal about, was strikingly like a very minute
tortoise, the resemblance being heightened when the animal was viewed fiom the side.

" Kod-like alga? of minute size, the larva; of Crustacea, especially the vast numbers of extremely
small larval Copepoda, must enter as a perceptible factor into the food supply of the Oyster.

" There is no doubt but that the comparatively quiescent condition of the headwaters of these
inlets and creeks, available as oyster-planting grounds, are more favorable to the propagation of
minute life than the open bay or creeks, where the temperature is lower and less constant. Prac-
tieally, this is found to be true, for oystermen seem to be generally agreed that Oysters ' fatten'
more rapidly, that is, feed more liberally in the headwaters blind extremities of the creeks than
elsewhere. This notion of the oystermen is in agreement with my own observations during the past
year. Oystermen also assert that Oysters 'fatten' more rapidly in shallow waters than in deep
ones, a point n\wi\ which I made but few observations; but such as I did make tended to confirm
sueh an opinion. In illustration I may contrast the condition of the Oysters in the pond leased by
the commission at Saint Jerome's and those dredged off Point Lookout, in twenty or thirty feet of
water, on the 3d day of October, 1880. The Oysters in the pond, by the middle or end of September,
were in good condition as to flesh, and marketable, while those from deeper water off Point Lookout,
and but little later in the season, were still extremely poor, thin, and watery, and utterly unfit for
market. These differences in condition, it seems to me, are to be attributed in a great measure to
differences of temperature and the abundance of fowl, but mainly to the latter."

These observations give us some hints regarding the advantages arising from the cultiva-
tion of Oysters in more or less stagnant water, in which, as in the French parks or claires, an
abundance of microscopic life would be generated in consequence of a nearly uniform temperature,
higher in the early autumn months at least than the waters of the open sea, where cold currents
also would tend to make it still less uniform and thus interfere with the generation of the minute
food of the Oyster. In other words, it would appear that the effect of the French method is to
furnish the best conditions for the rapid and constant propagation of an immense amount of
microscopic food well adapted to nourish the Oyster. That unlike Oysters expos-ed to a rapid flow
of \\ ater on a bottom barren of life they grow and quickly come into a salable condition.

Sin \ i IONS BEST ADAPTED FOB OYSTER CULTURE. In this country narrow coves and
inlets with comparatively shallow water appear to furnish the best conditions for the nutrition
and growth of Oysters; and according to my own experience these are the places where we act-
ually find minute animal and vegetable life in the greates: abundance, and, as might have
been exited, the Oysters planted in such situations appear to lie in good condition early in
the autumn, long before those which arc found in deeper and more active water, where their



732 NATURAL HISTORY OF AQUATIC ANIMALS.

food has less chance to multiply. If the French mode applies successfully to an inferior species,
ours, which grows so much more rapidly, ought to derive a proportionally greater benefit from
being treated in tbe same manner. However, before we are ready to deal with the material
on which the Oyster feeds, we desire a more perfect acquaintance with the microscopic life
which grows upon oyster-beds and swims about in the adjacent waters. From the fact that
the lower forms of life in fresh water often appear in great abundance one year, while in the
next, from some unexplained cause, none of the same species will be found in the same situation,
we may conclude that similar seasonal variations occur in the phases of the microscopic life of
a given oyster-bed and its vicinity.

INFLUENCES OP ENVIRONMENT. Such yearly variations in the abundance of microscopic
life are probably the causes of the variable condition of 1 he Oysters taken from the same beds
during the same season of different years. Violent or sudden changes of temperature are prob-
ably often the cause of the destruction of a great amount of the minute life upon which the Oyster
feeds. Backward and stormy seasons doubtless also affect the abundance of the microscopic life
of the sea. All of these questions have, however, as yet been scarcely touched, and, judging from
the disposition of many of our students of zoology to be content merely with a description of new
species and the compilation of lists, instead of also entering into investigations of the life-histories,
the relative abundance of individuals, and the influence of surrounding conditions upon the
forms they study, it will take some time yet before we get the information so much desired.
When we arrive at this knowledge we will know why it is that Oysters taken from a certain bed
are in good condition for a season or two and then for one or more years are found to be watery and
of poor quality, as well as why it is that the Oysters of certain beds, which for years have had a
high reputation for their fine qualities, are suddenly found to be more or less green in the beard,
as I have been informed is now the case with the Oysters of Lynn Haven Bay, Virginia.

As to the influence of brackish water in improving the condition of Oysters, let me observe
here that those who hold to that opinion appear to forget to bear in mind that brackish- water beds
are often in the case just described ; that lying in shallow, relatively quiet water, an abundance
of food is generated which is rapidly consumed by the animal?, quickly bringing the latter into
condition, the brackish state of the water getting the credit of the result.

" In a paper published in the report to the British Government on oyster-culture in Ireland,
in 1870, Prof. W. K. Sullivan, of Dublin, remarked that independently of the mechanical constitu-
tion of the shore and littoral sea-bottom, i. e., deposition of sediment, the currents, the temperature,
etc., the nature of the soil produces a marked influence upon the food of the plants and sedentary
animals that inhabit the locality, as well as upon the association of species. Especially is it the
case with Oysters, that the soil exerts so much influence on the shape, size, color, brittleness of
shell, and flavor of the meat, that an experienced person can tell with great certainty where any
particular specimen was grown. 1 . . . Were we able to determine the specific qualities of
the soil which produce those differences in the qualities of Oysters, it would be an important step
in their cultivation. Again, soils favorable for the reproduction of the Oyster are not always
equally favorable for their subsequent development; and, again, there are many places where
Oysters thrive but where they cannot breed. This problem of the specific influence of the soil is,
however, a very difficult and complicated one. First, because it is almost impossible to separate
the specific action of the soil from that of the other causes enumerated ; and next, because, though
much has been written on the subject of Oysters, 1 do not know of any systematic series of experi-

'E. INOKBSOLL: Report on Oyster Industry, Tenth Census.



PROTOZOANS OF SAINT JEROME'S CREEK. 733

incuts carried out upon different soils, and for a sufficient length of time to enable accidental
causes to be eliminated, which could afford a clue to the determination of the relative importance
of the action of the several causes above enumerated at the different stages of development of the
(hster. . . . I believe the character and abundance of Diatomaeea and Rhisopoda, and other
microscopic animals, in Oyster grounds, is of primary importance in connection with Oyster
cultivation. The green color of the Colchester and Marennes Oyster shows how much the quality
may lie all'eetcd liv such organisms. 1 1 is pioliaMc that tlic action or inllnenec of t lie >ml of <>\MCI
grounds upon the Oyster, at the various stages of its growth, depends mainly upon the nature and
comparative abundance of the Diatomaeea, Rhizopoda, Infusoria, and other microscopical organisms
which inhabit the ground. I have accordingly always noted where the mud appeared to be rich in
Diatonittcrtt, Foraminifera, and other microscopic organisms. A thorough a study of a lew differently-
situated Oyster-grounds, exhibiting well-marked differences in the character of the Oyster from
this point of view, by a competent microscopist, acquainted with the classes of plants and animals
just mentioned, would be of great scientific interest and practical importance."

PROTOZOANS OP SAINT JEROME'S CREEK. The Protozoan fauna of Saint Jerome's Creek
presents considerable variety; several species of test-building Cothurnia were noticed, one
Vaginicola, three species of Vorticella or bell-animalcules, free-swimming Euplotes, A'a*te; of
the latter type an exceedingly elongate form was noticed, with a body almost as slender as a
thread-worm. Monads were noted sometimes in profusion, though some of these may have been
the spores of algae. Amreboid forms were very few, and the only one which was frequently
noticed was a form so nearly like Actinophry* sol that I would pronounce it the same.

The Freia producta Wright was most common ; this creature is related to the fresh-water
trumpet animalcules, and is one of the most beautiful Protozoans I have ever seen. I reproduce
here, with some changes, my description of the Chesapeake form from the "American Naturalist*
for November, 1880 :

" The tubes in which the animalcule resides are formed of a narrow transparent ribbon of
horny consistency, wound into a spiral and terminating in a trumpet-shaped extremity, from which
the odd peristome of the inhabitant protrudes. The basal or attached end is usually tent at an
angle to the tube and bears a striking resemblance to the foot end of a stocking resting upon the
sole. This portion is not composed, like the tube, of a spiral ribbon, but is simply a thin-walled
sac, from the open end of which the ribbon takes its rise, but it is composed of the same kind of
material. Many of the tubes show a trumpet-like rim projecting from the sides of the former, a
little above the middle, and of the same form as the terminal rim, showing that this, like the form
described by Mr. Wright from British waters, may stop building its tube for a time and then
recommence.

"The adult animal, tube and all, when fully extended, will measure one twenty-fifth of an
inch in length. It is of the same color as Stentor ceeruleus, or bottle-green, but has the power of
elongating and twisting itself as greatly as S. rceaeli. The peristome is quite unlike that of Freia
ampulla and bears a strong likeness to the blades of a pair of obstetrical forceps. The blades are
deeply grooved, forming a deep ciliated demi-caual with parallel sides, and at the junction of their
bases lies the spacious, twisted, and spirally ciliated pharynx, which is bounded dorsally and
ventrally by the prominent folds which unite on either side with the long, curved lobes of the
peristome. There is a small basal disc as in Stentor, and the ectosarc is traversed as in that genus
by parallel granular bands, regarded as muscular fibers by some writers. The usual food-balls
and vacuoles are present, and I was enabled to define sharply the endosarc from the ectosarc,



734 NATURAL HISTORY OF AQUATIC ANIMALS.

and clearly see the nucleus. The tube or ribbon-secreting organ described by Wright I was unable
to discover.

" When fully extended the basal portion of the animal becomes attenuated to a thin bluish
lilaineut, which widens towards the peristome, where the body is over half as thick as the inside
diameter of the tube. When fully retracted and resting, the animal resembles in its oblong shape
a retracted and resting Stentor, and measures about ^ as long as when fully extended. The
ribbon which forms the tube makes from four to twenty-four turns in specimens of different ages."

This organism I since find to be an inhabitant of the bay also, but is not so abundant as in
the creek. Small mica collectors fixed to floating corks in the hatching jars and aquaria used
during the past season were found to afford a nidus for Freia as well as Zoothamnium, the latter
multiplying at a most astonishing rate in a very few days. Under similar conditions, amoebae,
apparently A.proteus, multiplied at a suprising rate; this was the case, too, with a small brown
diatom which would coat in three or four days the sides of the glass vessels with a thin brownish
film composed of countless myriads of individuals of the one species. The temperature of the
bay-water used in the aquaria at this time would range from 76 F. to 89 F. The Vorticellidw
also soon attach themselves, and next to the hypotrichous iufusoriaus found in the locality are the
most important animalcular forms found in the Chesapeake. At the mouth of the Cherrystone
River I last year found Licnophora cohnii in great abundance eutoparasitic upon an unidentified
hydroid. The ]\e\iozoi)u,Actinophrys sol, is found in the bay and Saint Jerome's Creek, and I think
it capable of swallowing dead or enfeebled Oyster eggs and embryos.

MUTUAL RELATIONS BETWEEN THE OYSTER AND ITS PREY. Mobius calls an Oyster-
bank a Bioccenosis or interdependent community of life. The many species of animals found
on the banks and beds are no doubt more or less mutually dependent upon each other for
subsistence, but this is perhaps not any more true of Oyster-banks than it is of terrestrial
fauna;. There are no doubt vast numbers of floating embryos of Oysters .eaten by other
animals growing on the beds which bring their food supply to themselves by means of
currents produced by ciliary motion. On the other hand, there are no doubt vast numbers of the
minute swimming embryos of these, drawn in and swallowed by the Oyster, which may, indeed,
for aught we know, in this way swallow many of its own young, for the current produced by the
Oyster by means of the cilia clothing its gills is by no means a feeble one, though it is exceeded
in power by the current flowing into and out of the siphons of Mya. In the latter I have frequently,
upon opening the animal, found several Copepoda plainly visible to the naked eye swimming
about in the water in the inferior mantle cavity, which had evidently been drawn in by the inward
current. It is plain in this case that very mild means may become effective as prehensile and
destructive agents, so as to bring remotely related types into intimate vital relations.

Though an animal may be apparently invulnerable on account of the effectiveness of its
covering, it cannot emancipate itself from the abiding struggle it has to make to obtain food, no
matter how passively it may appear to conduct itself. The Oyster has sucb a character, yet it has
been apparent from what has been observed before, that it is entirely dependent for a vigorous
existence upon the favorableness of surrounding conditions. The beds and banks in a true sense
are interdependent communities, whose vigor may no doubt be impaired by the removal of a single
one of its members. Suppose we should take away the algae, diatoms, Oyster-crabs, vibrioi^,
bacteria, infusoria, in fact all the minute life; we should greatly impair if not destroy the vitality
of the beds. While it is true that many of even the smallest forms may destroy food which
should properly be consumed by the Oyster, that were it not for the presence of these same small
forms some destructive element might attain such a development as to be more injurious still.



CAUSE OF THE CIM.KN COLOR OF THE OYSTER. 7:;;.

There is therefore no doubt hut that a delicate balance of power is maintained by these rivals
which is best fur tin- health of tin- community. The stabilitx of permanent o\ sicr l.c.K, it must
lie remembered, t'lirnislics ilic right conditions for the survival of many types. It is a place where
tli. \ tind lioth a home and pleat}" of food. It is the very fa vonibleness offered by tlu.se places
which tends to induce them to congregate and multiply, and it becomes a serious question whether
the artilicial establishment of banks will not in time cause the proper. types to congregate and
multiply so as to Milord the needed food supply for the Oysters. That destructive members of the
community may also he attracted is admitted, but if the beds are established in shallow waters, as
I have pieviously suggested, the destruction of such unwelcome intruders may be very readily
c Heeled. Drills" and boring-sponges are naturally to be thought of a types which should be
destroyed, while diatoms, infusoria, small polyps, bryozoa, minute alga?, etc., are to be favored in
CM -:-\ wa\. Those forms again which the oyster-culturist knows are only there for the purpose
of -jetting a good living with little trouble to themselves ought to be destroyed.

It might be an advantage to introduce certain desirable forms onto a bank, which might be
supposed to be useful as a food supply. Infusoria and diatoms not previously existing might be
introduced in this way; this, I think, would be especially easy in the case of the former where
the tyi>e was one which is fixed during its adult life.



216. ON THE CAUSE OF THE GREEN COLOR OF THE OYSTER.

EXPERIMENTS AT WASHINGTON AND PHILADELPHIA. I have frequently read accounts of
Oysters which had become green-fleshed in certain localities, and it has also been asserted that
competent chemists had discovered poisonous green substances of metallic origin in such s|tuci-
moils. Tests made at the Smithsonian Institution by Professor Endlich in 1879 failed to disclose
anything poisonous in some green Oysters which had excited the suspicion of the Board of Health
of the city of Washington. This investigator, it is desirable to state, resorted to every test known
to him in order to discover if anything poisonous was present, and failing to discover any harmful
substance concluded that the color must be due to some inert material. In order to set; if tin- color
was due to the presence of some green compound of copper, Prof. H. C. Lewis, of the Academy of
Natural Sciences of Philadelphia, kindly made some delicate tests for me, using small dried frag-
ments of an Oyster very deeply tinged with green in various regions, especially in the liver, con-
nective tissue, and mantle. The fragments were burned in a bead of microcosmic salt and chloride
of sodium on a clean platinum wire in a gas dame; this test did not give the characteristic sky-
blue flame which should have been developed had there been the minutest trace of copper present.

It is therefore clear that the substance, whatever it may be, is not a corrosive metallic poison
derived from copper, which if present would almost undoubtedly be detected by a peculiar acrid
metallic taste, which would be experienced when one ate eucu Oysters. In making some practic.il
tests as to the relative qualities of such Oysters as compared with white Meshed ones. op|M>r
tunities for which were kindly furnished me by Mr. J. M. Carley, of Fulton Market, I faded to
detect the slightest difference of flavor. Such also is Professor Leidy's verdict, who informs
me that he made a similar experiment, and a restaurateur, with whom I discussed the matter,
declared that he was in the habit of selecting them for his own eating, preferring their flavor to
that of the white O.. store.

VARIATIONS IN COLOR. If it be objected that the green color indicates an unhealthful
condition of the animal, it may be stated that other color variations of the flesh have fallen



736 NATURAL HISTORY OF AQUATIC ANIMALS.

under my observation recently. What is now alluded to is the yellowish, verging toward
a reddish cast, which is sometimes noticed in the gills and mantle of both the American and
European species. This, in all probability, like the green color, is due to the reddish-brown
matter which is contained in much of the diatomaceous food of the animal.

Mr. J. M. Carley has also called my attention to these variations, and was inclined to attribute
them to the soil in the vicinity of the beds. But if the classical writers are to be trusted, to the
green, yellow, and white fleshed sorts we must add red, tawny, and black fleshed ones. Pliny
tells us of red Oysters found in Spain, of others of a tawny hue in Illyricum, and of black
ones at Circeii, the latter being, he says, black both in meat and shell. Horace and other writers
awarded these the palm of excellence. (O'Shaughnessy.) However, the black appearance may
only have been due to an abundance of the natural purple pigment in the mantles of the animal,
which varies very much in different forms; some, judging from the dark purple color of the whole
inside of the shell, must have the whole of the mantle of the same tint. The amount of color in
the mantle, especially at its border, varies in local varieties of both the American and European
species, as may often be noticed.

Sometimes almost the whole of the outside surface of the mantle is charged with dark purple
pigment cells. That copper is not usually the cause of the green color of Oysters I also have the
additional testimony of Prof. W. K. Sullivan, of Dublin, who says :

"As the green color of the mantle of Oysters from certain localities just referred to is
commonly attributed to copper, and as such Oysters are consequently believed very generally to
be poisonous, and their value therefore greatly depreciated, I made the most careful search for
traces of that metal in the muds which I had received from grounds known to produce green-
bearded Oysters. Oysters and other mollusca placed in solutions containing copper and other
metals absorb them and retain them in their tissues. I have had two or three opportunities of
examining Oysters which had assimilated copper, owing to mine-water containing it being allowed
to flow into estuaries at places close to oyster-beds. In every case the copper was found in the
body only of the Oyster, which it colored bluishg-reen, and not in the mantle or beard, which was
not green. In the green-bearded Oysters which I have had an opportunity of examining, the body
was not green, and no trace of copper could be detected in any part of the animal. The color,
too, was not the same as that of the true copper Oysters, but rather that which would result from
the deposition of chlorophyl or other similar chloroid vegetable body in the cells."

The American consumer, however, need not be alarmed about the presence of copper in our
species, as there are no beds on our eastern coast into which the washings from mines ever flow,
as we have no workable deposits of copper near any of our beds, as in Cornwall, England. Besides,
I am inclined to doubt the statement of Professor Sullivan that Oysters or other mollusks can
absorb copper salts until their tissues are " colored bluish-green." Every competent histologist
knows how very readily organisms are killed by the action of inorganic acids and salts, several of
which are constantly used by biologists in fixing histological characters. Liebig, in his "Animal
Chemistry," long ago pointed out that the oxides and metallic compounds of antimony, arsenic,
copper, and lead had a very remarkable affinity for protoplasm, producing its immediate death.
In consequence, he suggested a very high chemical equivalency for living matter. This has since
been confirmed by the studies of Loew and Pokoruy, who found that silver nitrate would produce



Online LibraryG. Brown (George Brown) GoodeThe fisheries and fishery industries of the United States (Volume 1:1) → online text (page 122 of 146)