Full text of "Shellfish contamination from sewage-polluted waters and from other sources"

See other formats

COMMERCIAL TURPENTINES.

Minimum

ti'SS

2*jp

06 ^>o ^5

PQfiQQC

Polymerization.

Refrac-
tive index
of residue.

1111

:82§S?^

*O O O O
•-H o Q (N

• io>c»cicir

Per cent
residue.

•^ O (M O OO OO •t1 00 •"»* 1C ** (MO O

OjOO'-H'-i ' ''CO t-HIO rH

j||?

g : i

— u
»H +3'® «o

«^^s

i i i

!|i

S : :

• o o •
••-ooo

10 »o
t>- o

£?£?

1 11 1

A M ~

IlEi

si 11 S

1 1

•32

. — • co
W

A3 '

.—

—

Pure turpentine
do

Spirits of turpentine...
Pure brand turpentine.
Pure tiirnflntine-

c
T:

Pure spirits of turpen-
tine.
Pure turpentine
Pure spirits of turpen-
tine.
Turpentine

Clarksville, Tenn...
Washineton. D. C. .

Washington, D. C.
do

Danville, Ky
Cincinnati, Ohio. .
Washington, D. C.
do

! if }

|| |

Issued April 19, 1911.

U. S. DEPARTMENT OF AGRICULTURE,

BUREAU OF CHEMISTRY -BULLETIN No. 136.

H. W. WILEY, Chief of Bureau.

SHELLFISH CONTAMINATION FROM SEWAGE-
POLLUTED WATERS AND FROM
OTHER SOURCES.

GEORGE WHITFIELD STILES, JR.,

In Charge, Bacteriological-Chemical Investigations.

WASHINGTON:

GOVERNMENT PRINTING OFFICE.
1911.

LETTER OF TRANSMITTAL.

U. S. DEPARTMENT OF AGRICULTURE,

BUREAU OF CHEMISTRY,
Washington, D. C., August 26, 1910.

SIR: I have the honor to submit for your approval a report pre-
pared by G. W. Stiles, jr., bacteriological chemist of this Bureau, on
the contamination of shellfish by sewage-polluted water. The data
reported are based on an extensive and painstaking investigation
during which many localities have been inspected, the conditions care-
fully studied, and all the bacteriological data possible obtained. The
latter were found to corroborate the observations made during inspec-
tion. To no one, not even the consuming public, will this report be
of greater interest and benefit than to the industries concerned. That
Ihe danger noted exists to some degree in many localities no one can
deny, and that the danger is one that will increase unless intelligent
and efficient measures are taken to control it is equally obvious. The
investigations presented in this manuscript are of direct importance
to a proper consideration of such steps as may be indicated under the
food and drugs act to protect the public health, and to avoid decep-
tion. The report is in no sense intended to discredit the valuable in-
dustries concerned, but rather to point the way in which the products
of these industries may be accepted with greater confidence by the
public. It is believed that this report will assist in the furtherance
of this purpose, and I recommend that it be published as Bulletin 136
f the Bureau of Chemistry.

Respectfully, H. W. WILEY,

Chief of Bureau.
Hon. JAMES WILSON,

Secretary of Agriculture.

CONTENTS.

Page.

Introduction 7

Experimental investigations 9

Plan of work 9

Procedure for bacteriological examination 9

Collection and shipment of samples 9

Preparation of samples of shellfish 10

Media employed 11

Plating samples 11

Water 11

Oysters 12

Identification of organisms 12

Pure cultures 12

Bacillus enteritidis sporogenes determination 13

Description of isolated organisms resembling Bacillus typhosus 13

General characteristics of the Bacillus coli organisms isolated 14

Sources of contamination 15

Location of oyster beds 15

Bacteriological results on shellfish and sea water 16

Comparison of results obtained on samples from known sanitary

and insanitary grounds 19

Floating oysters in polluted water 20

Inspection data 20

Laboratory results on floated oysters 24

Discussion 26

Storage of oysters 28

Spoilage due to length of time out of water 28

Diseased and green oysters 29

Handling of shucked oysters 30

Insanitary oysterhouses 31

Washing oysters 33

Character of containers 35

Insufficient cooling 36

Souring due to age 36

Graphic presentation of results by two methods of handling 37

Cooking tests 37

Collated opinions on sewage contamination : 40

Transmission of disease by infected shellfish 40

Presence of Bacillus coli and Bacillus typhosus in oysters 42

Vitality of Bacillus coli and Bacillus typhosus in sewage-polluted water and

in shellfish 44

Significance of sewage organisms in food supplies 45

Summary 48

Bibliography 50

ILLUSTRATIONS.

Page.
FIG. 1. One of three main sewers emptying untreated sewage into the mouth

of a river '. 15

2. Oyster floats in sheltered artificially constructed inlets from the bay. . 21

3. An abandoned oyster float 21

4. Two oyster floats anchored in the rear of oysterhouses ,. 22

5. A closer view of the upper oyster floats shown in fig. 4 23

6. Oyster floats located near a shucking establishment 24

7. Dumping city refuse to fill a depression within 50 yards of oyster floats . . 26

8. View at low tide showing dead hog covered at high tide by water wash-

ing oysters on a float within 150 feet 27

9. About 500 boats and as many floats in operation in river 28

10. Oyster floats between the row of oyster boats (fig. 9) and the shore 29

11. Shucking oysters „ 32

12. Another shucking establishment showing insanitary conditions 32

13. Clam diggers' huts, where shucking is done 33

14. Various types of containers for shipping oysters, as used by the trade 36

15. Comparison of results obtained by handling the same lot of oysters in

two ways 37

SHELLFISH CONTAMINATION FROM SEWAGE-POLLUTED
WATERS AND FROM OTHER SOURCES.

INTRODUCTION.

The contamination of shellfish from sewage-polluted waters presents
sanitary problem of increasing importance to those interested in the
>roduction of pure-food supplies. Until comparatively recently there
las been but little apprehension in this country regarding the injury
;o oysters and other shellfish from this source, but food officials and
anitarians are now awakening to the fact that either sewage must not
>e promiscuously emptied into our natural bodies of water or the shell-
ish industries must in many cases be removed to points far distant
Tom their present locations. Thorne67 says:a "It is only within
ecent years that the need of protecting oyster fisheries against sewage
pollution has forced itself on the attention of those who have the
esponsibility for protecting the public health. "
When the great cities of to-day were mere villages, and what are
ow villages were green meadows, the wastes of man's activities were
omparatively insignificant, but conditions are now very different,
nd with the present rapid increase in population the situation will
>ecome more and more serious. In fact, cities and villages in the
)ast did not require complicated means of sewage disposal, yet this
roblem to-day has grown to such an extent that many city and
tate health officials are taking active steps to remedy the evils
Iready arising from present conditions. In the light of present
anitary knowledge and in consideration of the results obtained from
nvestigations made in this Department and elsewhere, it is known
hat sewage-polluted water is a menace to the shellfish industries.
Such insanitary conditions can not continue to exist without increas-
ng the probability of disease dissemination through the agency of
nfected oysters and other shellfish when used as food, especially when
oMsumed raw.

The problem of sewage disposal is of national importance, and is
not confined to one locality nor to a single industry. The health

a Reference numbers refer to bibliography, see p. 50.

8 SHELLFISH CONTAMINATION FROM SEWAGE-POLLUTED WATERS.

of every man, woman, and child is influenced by the properly or
improperly cared-for wastes of their own community. Since the
seriousness of the situation and the need of better regulations is
realized, every city and village should adopt proper methods of sewage
disposal, so as to prevent further pollution of .the natural waters; not
alone to protect the extensive sea-fish industries, but as a sanitary
precaution to safeguard the health and lives of millions of people.

In speaking before the Conference of Sanitary Officers at Albany,
N. Y., Dr. Sedgwick60 touched the vital point when he expressed the
need of better sanitary regulations in the following terms :

The modern sanitarian looks upon dirt not merely nor even chiefly as esthetically
objectionable. He sees in it rather the vehicle of many of the worst diseases that
afflict the race.

Moreover dirt is not always dry or solid but often wet, fluid, and liquid. Nor is it
always concentrated but often dilute, and some of the worst forms of dirt are little
streams of sewage which find their way into drinking water, and, unseen and unsus-
pected, attack and destroy their victims.

We hear much nowadays of pure-food supplies, pure-water supplies, and pure-air
supplies; but the removal of the wastes and refuse from our cities, towns, villages, and
farmhouses is equally important. For it is with the social organism, the municipality,
the village, the family, very much as it is with the human organism; to retain putrefy-
ing wastes within their borders is an evil similar in character to that which arises in
the human body from undue retention of urine or bowel contents. Poisoning ensues
in the one case almost as certainly as in the other. * * *

But we have learned our lesson. In the hard school of experience we have learned
that hundreds of epidemics of typhoid fever and Asiatic cholera have come from the
use of drinking water tainted with sewage, barely stained it may be with little
trickling streams of water soiled with human excrements. And this it is which has
given rise to the great problem of sewerage and sewage disposal. This it is which has
caused numerous commissions, especially in western Europe and America, to study
elaborately the pollution and purification of rivers.

The shellfish interests which are engaged in the solution of this
problem rank among the most important industries of the country.
It is estimated that in 1904 there were more than 25,000,000 bushels
of oysters marketed in this country, valued at nearly $20,000,000.
The operations of the various shellfish industries extend from Maine
to the Gulf of Mexico on the Atlantic and over a considerable territory
along the Pacific coast. Vast areas of sea bottoms are utilized for the
purpose of growing oysters, and many men are engaged in the various
branches of the industry. An extensive business is also being devel-
oped in maturing seed oysters taken from the Atlantic coast and
transplanted in the colder waters of the Pacific, notably in the region
of Puget Sound, where the conditions are unfavorable for spawning
and development.

It is* apparent that a grave danger threatens a valuable industry as
well as the public health, and from this point of view the investigation
was undertaken to determine the nature and extent of the danger
and to suggest, if possible, methods of meeting and overcoming it.

BACTERIOLOGICAL PUOCK1HJKK. 9

EXPERIMENTAL INVESTIGATIONS.
PLAN OF WORK.

This investigation is concerned primarily with the possibility of
oysters and clams becoming contaminated when grown or " floated"
in waters polluted from sewage. Similar examinations of oysters
from localities comparatively free from sewage are considered as
standards in connection with those examined from suspicious sources.
Practically all of the samples, including oysters, clams, and water,
were collected by the writer from their original sources. At the
time of dredging or tonging the shellfish from their natural or arti-
ficial beds, samples of water were collected in sterile bottles for
bacteriological examination. When oysters were allowed to " drink,"
"fatten," or "float" in brackish regions, samples of the water from
the floats were also collected to compare with the oysters thus
treated. These investigations were carried on at different points
along the Atlantic coast and the Gulf of Mexico during the oyster
seasons of 1908, 1909, and 1910.

PROCEDURE FOR BACTERIOLOGICAL EXAMINATION.
COLLECTION AND SHIPMENT OF SAMPLES.

In order to obtain the samples it was necessary to secure the
cooperation and services of practical oystermen actually engaged
in the business. Boats properly equipped with dredging and tong-
ing facilities were used, and at the time of collection careful notes
were made as to probable sources of pollution, depth of water,
direction of winds, conditions of tide, etc.; in fact any information
which was thought to be pertinent was recorded.

During the first part of the investigations water samples were
collected in 2-ounce, glass-stoppered bottles protected by metal-
covered cylinders, the whole package having been sterilized at
160°- 170° C. for at least one hour. Later, 4-ounce, glass-stoppered
salt-mouth bottles, protected by aluminum cases, were used. Each
half of these aluminum cases is numbered and the top and the
bottom screw firmly together, making a water-tight package. The
numbers facilitate the making of records and they also prevent the
separation of properly fitted tops and bottoms. This particular
kind of container was devised in this laboratory and is admirably
adapted for shipping perishable materials.

Six of these metal cases are inclosed within a rectangular gal-
vanized iron box, 6 by 8 by 5 inches, outside measurement, the
cover being fastened with a clasp in order that the package may be
sealed. This metal box is inclosed within a wooden box of sufficient
size to permit a 3-inch air space to surround it on all sides, top, and
bottom. Heavy, grooved, upright pieces in each corner strengthen
72743°— Hull. 136-11 2.

10 SHELLFISH CONTAMINATION FROM SEWAGE-POLLUTED WATERS,

the box and at the same time hold the metal box firmly in place.
On the top of each wooden upright piece a button keeps the box
from slipping up and down should the package be turned bottom
upward. Cracked ice and sawdust, or ice alone, is packed in the
air space for refrigeration. The lid of the box may be left unlocked
to permit re-icing during long shipments, provided the inner box
is sealed.

The earlier samples of water and shellfish were shipped to the
laboratory in ice-cream freezers during moderately warm weather,
but when the weather was extremely cold no ice was used in shipping
short distances. Both water and shellfish samples were protected
from melting ice during shipment by being placed in water-tight
containers surrounded by ice.

Deep-water samples were taken by the aid of a heavy cylindrical
jacket made of lead, arranged in such a manner as to hold the bottle
in place, at the same time permitting the stopper to be lifted a given
distance by a string or wire without removing it the full distance
out of the neck of the bottle. A rubber band attached to each side
of the clamp grasping the stopper caused it to fly back in place
when the attached string was released. Surface samples were
taken as near 1 'foot under surface as was practicable.

Oysters and clams were fished from their beds either by tongs or
by dredges, each sample being properly labeled for future identifi-
cation. Generally about 12 to 15 medium-sized oysters or 6 clams
constituted a sample.

PREPARATION OF SAMPLES OF SHELLFISH.

(1) Clean shells by thorough scrubbing with a brush in running
tap water, rinse in sterile water, dry between folds of a sterile towel.

(2) Cleanse the hands thoroughly after scrubbing the oyster
shells, select five cleaned oysters, slightly flame the lips of each shell
before opening, and open with a sterile oyster knife, observing
aseptic precautions, keeping deep shell downward. Either draw off
liquor with sterile pipette or decant into sterile flasks.

A summary of the chief advantages of examining the whole oyster
and liquor is given by Houston 33 as follows:

(1) It is a definite quantitative method, succeeded by qualitative records.

(2) It gives the average volume of the whole contents of the oyster shell.

(3) It yields results based on collective examinations of ten oysters.

(4) It includes the examination of the entire contents of the shell, not of a fraction

either of the liquor or the gastric or intestinal juice, or the mixture of these
liquids.

(5) The results can be stated as number of bacteria either per oyster or per cubic

centimeter of oyster.

According to the observations of the writer the total quantity of
oyster liquor and body range from about 8 to 20 cc, averaging

BACTERIOLOGICAL PROCEDURE. 11

decidedly higher than 10 cc per oyster, the average recorded hy
Houston. In some cases this average was as high as 15 cc per oyster,
including both liquor and body meat. The quantity of course
varied according to the size and shape of the oyster shell.

Some preliminary work was done in order to decide upon the best
and most practical method to follow. Individual oysters from the
same lot were treated in various ways. Oysters obtained from
clean, hard bottoms showed little difference in results when com-
pared with those from the same source thoroughly scrubbed. Oysters
from muddy bottoms showed the greatest necessity of cleaning
before being opened. Practically the same method with slight modi-
fications was used during the entire work. Only sound, representa-
tive stock was considered.

The examination of composite samples of five or more oysters was
supplemented by inoculating media with the liquor from single oys-
ters to determine the presence of Bacillus coli in each. It was also
decided to use only the liquor bathing the oyster, instead of both
meat and liquor, as the latter represents the character of the whole
contents of the shell sufficiently well to determine the presence of
pollution.

MEDIA EMPLOYED.

Plain agar and nutrient beef broth. — Prepared according to the standard methods
)mmended by the American Public Health Association.56

Bile salt agar. — Prepared after the formula of MacConkey 41 by adding 0.5 per cent
sodium taurocholate, 2 per cent peptone, 1 per cent lactose, and 1.5 per cent powdered
agar to a liter of water. To this mixture a sufficient quantity of a 1 per cent solution of
neutral red is added to give a light red color to the finished medium. The bile salt
agar is used as a differential medium for the isolation of B.-coli-\ike colonies. Plates
are incubated from twenty-four to forty-eight hours, when the colon bacilli, if present,
will appear as smooth, round, raised, entire, glistening, pink colonies.

Litmus milk fermentation tubes. — Used for the determination of the presence of B.
enteritidis sporogenes.

In addition to the media already mentioned, the following were
also tried, but because of unsatisfactory results their use was not
continued : Gelatin, lactose agar, litmus lactose agar, Endo's medium,
Hiss's agar, and plain agar without the addition of salt.

PLATING SAMPLES.
WATER.

Solid cultures. — In the routine water work the following cultures
are made for each sample:

(a) Plate 1 cc, 0.1 cc, 0.01 cc, and 0.001 cc on plain agar at 25° C.

(6) Same dilutions on plain agar at 37° C.

(f) Same dilutions on bile salt agar incubated at 37° C.

Plates are incubated from two to four days, according to temper-
ature.

12 SHELLFISH CONTAMINATION FROM SEWAGE-POLLUTED WATKKS.

Liquid cultures. — In order to determine the presence of gas-pro-
ducing organisms, bile containing 1 per cent of peptone and 2 per
cent of lactose is used, or 2 per cent dextrose fermentation tubes
are inoculated with 10, 5, 1, 0.1, 0.01, and 0.001 cc quantities of the
sample, provided no unusual pollution is suspected. With water
from polluted or questionable sources 1 cc quantities are first used
and then higher dilutions than are ordinarily employed. Fermen-
tation tubes of the old style are being replaced by small inverted
tubes, with one end closed. These are placed within a large test
tube containing a fermentable medium. Tubes of this form require
less space, and as a whole are more convenient for routine work.
When desired, a large number of such tubes containing the ox-bile
medium can be carried from place to place in making presumptive
tests for colon organisms. By using 1 cc pipettes, graduated in
tenths, the above-mentioned ox-bile medium may be inoculated with
1 cc and 0.1 cc quantities of water or oyster liquor. These tubes
can be incubated over a radiator and the general character of the
material determined with a fair degree of accuracy by noting the
presence of fermenting organisms in this medium. Such a test is of
course only tentative, but is of service in fieldwork.

OYSTERS.

The liquor removed from shell oysters is cultured in the same
manner as samples of water, except that 10 and 5 cc quantities are
not used. With market shucked oysters, in which the bacterial
count is likely to t>e much higher than in the shell stock, higher dilu-
tions are generally necessary.

Dilutions of water and oyster liquor are made by adding 1 cc of
the sample to 9 cc of sterile water in a test tube or small Erlenmeyer
flask, thus giving a dilution of 1 : 10. Dilutions of 1 : 100, 1 : 1000, etc.,
can be made by taking 1 cc of each lower dilution and adding to other
flasks containing 9 cc of sterile water. Sterile normal salt solution
is preferred by some workers. After making the dilutions each flask
should be thoroughly agitated (twenty-five times) in order to break
up masses of bacteria. With semisolid substances sterile glass shot
may be added to the liquid for this purpose.

IDENTIFICATION OF ORGANISMS.
PURE CULTURES.

The classifications of Chester 12 and of Miquel 46 were followed in
identifying species herein described. Well-isolated colonies on bile
salt agar were selected from plates containing colon-like organisms
and subcultures made in lermentation tubes. These cultures liad
been incubated for from twenty-four to forty-eight hours when ex
amined, and, if gas-producing, each culture was sown in the following

BACTERIOLOGICAL PROCEDURE. 13

differential media: (1) Plain agar slants, (2) peptonized beef broth,
(3) alkaline litmus milk, (4) potato, (5) Dunham's peptone solution,
(6) 2 per cent dextrose bouillon, (7) 2 per cent lactose bouillon, (8)
2 per cent saccharose bouillon, (9) nitrate broth,, and (10) gelatin, all
prepared according to -standard methods. Cultures were observed
from one to three weeks, and all except gelatin incubated at 37° C.

Morphology and staining. — In connection with the biological char-
acters on culture media the staining and morphological properties
were observed with each culture under consideration.

Motility: Determined in freshly prepared liquid gelatin, or slant
agar cultures.

Staining: Reaction to Gram's stain,, methylene blue, fuchsin,-etc.—
also stained for flagella when convenient.

Morphology: Form, arrangement, size, in volution .forms, spores, etc.

Some bacteriologists consider the great amount of work involved
in identifying the individual species of organisms as useless, but the
experience of this laboratory is quite to the contrary. Undoubtedly
more reliance can be placed upon given bacteriological results, if a
more exact knowledge of the contained organism is ascertained than
if such a detailed study is omitted. Little is known concerning the
specific action of the ordinary organisms such as molds, yeasts, and
common saprophytes which are encountered in routine work on food
bacteriology, and all information along this line is of value. A
thorough study of the chemical nature of the bacterial products
elaborated by the growth of saprophytic as well as pathogenic
bacteria would also add materially to the value of the results obtained
from the biological side of the investigations. These results should
be further confirmed if possible by animal inoculation^ with the
isolated bacteria or their toxins.

BACILLUS ENTERITIDIS SPOROGENE8 DETERMINATION.

From a number of samples of water and oyster liquor 10 cc quan-
tities were heated for fifteen minutes at 80° C., and from each sample
thus treated 1 cc and 0.1 cc were inoculated into alkaline litmus milk
fermentation tubes to determine the presence of the Bacillus enteri-
tidis sporogenes. This organism was recorded as being present when
the medium coagulated with abundant gas formation within forty-
eight hours. Smear preparations from old cultures showed the pres-
ence of numerous spore-bearing organisms in the closed portion of
the tube.

DESCRIPTION OF ISOLATED ORGANISMS RESEMBLING BACILLUS TYPHOSUS.

Four different strains of motile organisms, somewhat resembling
Bacillus typhosus, were isolated from samples of water and oysters
collected during this investigation. The following general descrip-
tion illustrates the character of these organisms:

14 SHELLFISH CONTAMINATION FROM SEWAGE-POLLUTED WATERS.

Morphology and staining properties.— Gram-negative, more or less
actively motile bacilli, rods usually straight with slightly rounded
ends, varying in size from about 0.4 to 0.8 by 1.5 to 4 microns, gener-
ally somewhat longer and more slender than Bacillus coli. No
chains, spores, or capsules observed.

Biological characters. — Plain agar: Soft, grayish white, moderately
abundant growth.

Bile salt agar: Small reddish, slowly developing colonies.

Peptonized beef broth: Rendered uniformly turbid with no ring
or membrane.

Potato: No visible growth.

Alkaline litmus milk: Unchanged or faintly alkalinized after a
slight initial acidity.

Sugar solutions : No gas production in dextrose, lactose, saccharose,
levulose, maltose, nut rose, and iriulin.

Nitrate solution: Nitrates absent in three cases, heavy trace in
fourth.

Dunham's solution: Indol absent or present in slight trace.

Gelatin: Not liquefied, more or less circular flat, whitish growth
on surface, filiform stab.

Agglutination : Negative in two cases with 1 : 50 dilutions after one
hour, control stock culture agglutinated with 1 : 300 dilution of typhoid
immune serum after fifteen minutes. Owing to difficulty in securing
serum, the first two cultures were not tested. The typhoid serum
was furnished by the Hygienic Laboratory of the Public Health and
Marine-Hospital Service.

These cultures can not be classified as true types of Bacillus
typhosus, although biologically they closely resemble this general
group of organisms.

GENERAL CHARACTERISTICS OF THE BACILLUS COLI ORGANISMS ISOLATED.

MorpJiology and staining properties. — Gram-negative, feebly or
actively motile, rods generally short and ovoid with rounded ends;
size varying from 0.4 to 0.9 by 1 to 2.5 microns, with filaments occa-
sionally much longer. No spores, chains, or capsules jobserved.

Biological characters. — Plain agar: Abundant, soft, whitish-gray
growth.

Bile salt agar: Plates usually show moderate-sized, circular, yel-
lowish-pink colonies.

Peptonized beef broth: Densely turbid, usually a slight membrane
with ring and heavy sediment.

Potato: Brownish, abundant patch, darkening with age.

Alkaline litmus milk: Coagulated generally after two days at 37° C.

Rosalie acid solution: Unchanged.

SOURCES OF CONTAMINATION.

Sugars: Gas in dextrose, lactose, and saccharose, usually from
30 to 50 per cent, the ratio of CO2 to II equals 1 to 2. Acidity vary-
ing from 3 to 6 per cent.

Dunham's solution: Indol always present, either marked or in
trace.

Nitrates: Usually present, generally marked reaction.

Gelatin: Flat, whitish, irregular surface growth with filiform stab.
Commonly a few gas bubbles were seen in depths of medium without
liquefaction.

Agglutination: Not determined.

SOURCES OF CONTAMINATION.
LOCATION OF OYSTER BEDS.

The proper control and location of oyster beds in relation to public
health should be a matter of great concern to those engaged in the
industry. In selecting these it is not only essential that oystermen

FIG. 1. — One of three main sewers emptying untreated sewage into the mouth of a river. This sewage
combines with that from several other large cities and flows over extensive shellfish grounds.

should consider the localities best adapted to the growth, flavor,
size, and appearance of their oysters, but they must also consider
the possibilities of sewage contamination. Close proximity to any
habitation paves the way to possible pollution, and with the multi-
plication of dwellings the chance of dangerous contamination
increases.

Because of insanitary methods of sewage disposal large areas of
once valuable oyster grounds are at the present time subjected to
conditions which render the shellfish taken from them wholly unfit
for food purposes. (See Tables 1 , 2, 3, and 4.) On the other hand, it
will be observed that the investigations show extensive oyster layings
to be free from serious contamination, yet in these very localities

16 SHELLFISH CONTAMINATION FROM SEWAGE-POLLUTED WATERS.

summer cottages are springing into existence, the nearest villages
and cities are rapidly encroaching upon the oyster territory, and
the community does not concern itself especially about the disposal
of sewage. Even the oystermen themselves are guilty of contrib-
uting their quota of contamination by dumping wastes overboard
from boats or by depositing them in near-by waters through the
medium of privy vaults located in their shops. These closets are
almost invariably placed where nature is depended upon to remove
the accumulating wastes, which are later carried out by the waves to
some oyster float or bed near by.

BACTERIOLOGICAL RESULTS ON SHELLFISH AND SEA WATER.

•*•

The following tables show the bacteriological results obtained on
oysters and clams in the shell and on the sea water covering the beds
from which they were taken:

TABLE 1. — Results of the bacteriological examination of shell oysters.
COLLECTED FROM LOCALITIES REASONABLY FREE FROM EVIDENCE OF POLLUTION.

Bacteria

Sample No.

per cubic
centimeter
(plain agar
incubated

B. coli per
cubic cen-
timeter.

B. enteri-
tidis sporo-
genes.

four days

at25°C.).

6,300

11,000

1,000

4 ...

1,000

4,500

800

7 . .

6,000

Approximate average. .

4,300

COLLECTED FROM GROUNDS SHOWING PROBABLE POLLUTION.

1,500

10,000

400

500

5,000

400

100,000

7,000

27 000

10 . . .

17,000

20,000

8,000

5,000

1,500

15 ...

9,000

1 000

9,000

4,000

Approximate average . .

12,500

5.5

3.7

SOURCES OF CONTAMINATION.

TABLE 2. — Results of the bacteriological examination of hard clams (quahaugs) in the shell.
COLLECTED FROM GROUNDS WHERE INSPECTION SHOWED NO SERIOUS POLLUTION.

Bacteria

per cubic

Sample number.

centimeter
(plain agar
incubated

B. coli per
cubic cen-
timeter.

four days

at 25° C.).

300

2 700

32,000

4 ....

150,000

4 000

4,000

Approximate average

32,000

0.16

COLLECTED FROM GROUNDS SHOWING VERY SERIOUS POLLUTION UPON

INSPECTION.

13 000

11,000

1,000

1,122,000

1,000

2 108 000

100,000

100

12 000

100

60,000

1,000

Approximate average

489,000

460

Clams appear to contain a larger number of bacteria in their liquor
and body contents than do oysters. This may be explained in part
by the fact that the clams in the latter table were collected from
localities where extreme pollution was indicated. Each sample gen-
erally represented at least five clams, which constituted a composite
sample. In a few instances only one or two large clams were obtained
from a given locality for examination.

TABLE 3. — Results of the bacteriological examination of sea water over oyster beds.

COLLECTED FROM LOCALITIES WHERE INSPECTION SHOWED NO SERIOUS

POLLUTION.

Surface water.

Deep water.

Bacteria

B. enteri-

Bacteria

B. enteri-

Sample number.

per cubic
centimeter
(plain agar
four days
at 25° C.).

B. coli
per cubic
centi-
meter.

tidis spo-
rogenes
per cubic
centi-
meter.

per cubic
centimeter
(plain agar
four days
at 25° C.).

B. coli
per cubic
centi-
meter.

tidis spo-
rogenes
per cubic
centi-
meter.

130

100

500

700

100

200

300

7 .... ...

Approximate average

120

0.2

170

0.4

72743°— Bull. 136—11-

18 SHELLFISH CONTAMINATION FROM SEWAGE-POLLUTED WATERS.

TABLE 3. — Results of the bacteriological examination of sea water over oyster beds — Cont'd-
COLLECTED FROM LOCALITIES SHOWING PROBABLE POLLUTION.

Surface water.

Deep water.

Bacteria

B.enteri-

Bacteria

B.enteri-

Sample number.

per cubic
centimeter
(plain agar
four days
at 25° C.).

B. coli
per cubic
centi-
meter.

tidis spo-
rogenes
per cubic
centi-
meter.

per cubic
centimeter

four days
at25°C.).

B. coli
per cubic
centi-
meter.

tidis spo-
rogenes
per cubic
centi-
meter.

10,000

2,600

7,000

4,000

2,000

600

4,000

. 1

7 ....

400

200

300

100

2,300

500

Approximate average

2,500 I 0.6

1.7

1,500

2.7

These results, as a whole, indicate that in this case the deep water
was more polluted as regards B. coli and B. enteritidis sporogenes than
the surface water over the same locality.

TABLE 4. — Bacteriological examination of water collected over a distance of about 200
miles, a portion of which covers extensive shellfish grounds. (September, 1909.}

OVER OYSTER BEDS.

Bacteria per cubic

centimeter (plain

Sample
number.

Time.

agar incubated
three days).

B. coli
per cubic
centi-
meter.

Salt.

Remarks.

25° C. 37° C.

P. M.

Per cent.

1. .
2. ..

7.30
8.00

400

200

50
100

I
0

2.19
2.27

Near boat landing.
Out in channel.

3. ..

8.30

150

2.21

No gas in 1 cc.

4. ..

9.00

100

2.19

5. ..

9.30

2.02

6. ..
7. ..

10.00
10.30

800
150

200
90

0
0

2.00
1.95

Gas in 10 cc, none in 5 cc.
No gas in 10 cc.

8. ..

11.00

150

1.92

9. ..

11.30

100

1.70

10. ..

12.00

100

1.58

A.M.

11. .

12.30

1.57

Gas in 10 cc, none in 5 cc.

12. ..

1.00

1.59

13....

1.30

100

1.45

14. ...

2.00

1.26

15....

2:30

1.08

Gas in 10 cc.

3.00

400

100

.97

Gas in 5 cc.

UPPER LIMIT OF OYSTER BEDS.

17. . .

3.30

0.80

Gas in 5 cc, bubble in 1 cc.

18.

4.00

100

.54

Gas in 5 cc.

19.

4.30

400

200

.36

Bubble in 0.1 cc.

20.

5.00

.08

Bubble in 0.1 cc.

21.

5.30

200

100

.06

About 30 miles below citv.

22.

6.00

500

150

Trace.

About 20 miles below city.

23..

6.30

10,000

8,000

100

Trace.

Near landing below city.

24..

7.30

160,000

90,000

1,000

Trace.

Landing near sewer.

a Bubble.

SOURCES OF CONTAMINATION. 19

These samples of water were collected with difficulty from the
right lower deck, aft, on a steamboat while the wind was blowing a
gale and the sea was greatly agitated. They were taken in 4-ounce
sterile bottles hung at the end of a weighted line. At the upper
limit at which oysters grew to maturity the water had a saline con-
tent of from 0.97 to 1.08 per cent. Seed is said to set above this
point, but it does not mature well.

COMPARISON OF RESULTS OBTAINED ON SAMPLES FROM KNOWN SANITARY AND
INSANITARY GROUNDS.

The New York City Board of Health52 has demonstrated that the
beds from which oysters are taken for consumption in that city often
lie in grossly polluted waters. It is not the depredations of the star-
fish, borers, drumfish, etc., that threaten the life of the shellfish
industry, but the contamination by wastes. These practical facts
should stimulate every oysterman to see that his grounds are in a fit
sanitary condition and that they are kept fully protected from sub-
sequent contamination. Oystermen should not deceive themselves
by believing that their grounds are free from pollution, in the absence
of definite evidence to the contrary. If oyster growers can not
themselves determine the sanitary conditions of their layings, they
should appeal to their National organizations, or enlist the aid
and cooperation of their State shellfish commissions and boards
of health. A thorough sanitary survey of every oyster bed should
be made, and this should be supplemented by repeated bacteriological
examinations of both the water and shell stock taken at regular inter-
vals under varying conditions.

There are many factors which may influence the degree and extent
of sea-water pollution, and before passing judgment on the sanitary
condition of a particular oyster laying all the facts in the case should
be considered. The influence of tidal change, percentage of sunlight,
amount of rainfall, seasonal variations, prevailing winds and currents,
the depth, and the amount of salt in the water must all be consid-
ered, though of course the proximity to sources of possible contami-
nation is the most important item. Oysters offered for sale from
polluted beds are in constant danger of seizure and condemnation
by health officials. The occurrence of sewage matter in oysters can
not be tolerated from a public health point of view.

Where oyster beds are proved to be polluted or located in ques-
tionable territory, and it is desired to continue their use, there would
seem to be no objection to raising seed stock on such grounds for
transplanting purposes only. Oysters grown on such holdings
should under no circumstances be offered for sale to be consumed
either raw or cooked. Numerous experiments and the opinion of
practical oystermen indicate that oysters taken from polluted beds
"cleanse" themselves in a few days when placed in pure sea water.

20 SHELLFISH CONTAMINATION FROM SEWAGE-POLLUTED WATERS.

The length of time required for this cleansing process to be thor-
oughly accomplished undoubtedly varies according to local condi-
tions. At least one month should always be allowed for this change
to take place, although an entire season would be preferable.

Tables 5 and 6 show the sharp contrast between the bacteriological
findings on water and oysters from sanitary and insanitary grounds.

TABLE 5. — Bacteriological examination of water and shellfish collected from grounds
below the sewer shown in figure 1 .

SHELLFISH.

Bacteria per cubic
centimeter (plain

Sample
No

agar incubated
four days).

B. coli
per cubic
centi-

Salt.

Remarks.

25° C.

37° C.

Per cent.

6,000

100

Polluted.

40,000

30,000

1,000

Badly polluted.

WATER.

1...

900
6 800

700
2 000

10
1 000

1.19
.13

1 mile from sewer.
100 yards from sewer

1,800

700

1,000

.10

300 yards from sewer.

Extensive industries are being operated from the locality in which
these samples were taken, and the products are widely distributed.
The data given in Table 5 should be compared with the following
results obtained on shellfish and water taken from clean grounds:

TABLE 6. — Bacteriological examination of water and shellfish collected from clean grounds.

SHELLFISH.

Bacteria per cubic
centimeter (plain

Sample
No

agar incubated
four days).

B. coli
per cubic
centi-

Salt,

Remarks.

25° C.

37° C.

Per cent.

8,000

300

No pollution.

8 600

5 000

Do.

6,800

3,000

Do.

500

Do.

WATER.

I...

300

100

2.84

16 miles from land.

1,200

500

2.86

3 miles from land.

300

2.88

5 miles from land.

FLOATING OYSTERS IN POLLUTED WATER.
INSPECTION DATA.

When shellfish grounds are properly located with regard to sewage
disposal, it is not an uncommon practice to nullify the cleanly results
obtained by taking oysters from beds free from pollution and float-

SOURCES OF CONTAMINATION.

FlG. 2. — Oyster floats in sheltered artificially constructed inlets from the bay. The water of the sea does
not have the same cleansing action on coves of this kind as where action of the waves and currents is
unobstructed.

ing them for varying periods of time in water of a questionable
character before marketing. Fortunately this custom is being dis-
couraged or prohibited in some localities. Generally speaking, how-
ever, these floats are located for convenience rather than safety.
They are constructed with slatted bottoms having an area of about
20 by 40 feet, the sides being 1J feet in depth, and are usually found
anchored near the oyster establishment, where water is of a brackish
or moderately fresh character, and where the chances of sewage
pollution are greater than in the places where the oysters normally
grow to maturity.

FIG. 3.— An abandoned oyster float.

22 SHELLFISH CONTAMINATION FROM SEWAGE-POLLUTED WATERS.

This process of treating oysters in the shell is variously described
as " fattening," "feeding," "freshening," "floating," "bleaching,"
"drinking," or "plumping." By careful observation one can see
oysters on these floats open and close their shells, especially at the
beginning of flood tide. The least sudden jar or visible shadow will
cause them to close their shells immediately.

The method of floating oysters as ordinarily practiced is not a
true fattening process, but is only a means of increasing the bulk of
the oyster by adding to the water content and gives it a lighter color.
These changes are brought about by osmotic action caused by the
oyster being removed from comparatively salt water to a fresher
medium, and they will not occur when the oyster is floated in water
of the same saline content as that in which it was grown. Should
the water in which these floats are placed be polluted with sewage

FIG. 4.— Two oyster floats anchored in the rear of oysterhouses. Privy vaults are located in the rear of
these buildings, refuse being dumped directly into the river. It is a crime punishable by $100 fine to
float oysters in this river. An epidemic of typhoid occurred some years ago from oysters floated in
this place.

it is easy to see how the oyster may also become contaminated.
Oysters may increase in bulk from 10 to 25 per cent or more when
floated or when washed sufficiently long in running fresh water after
shucking. This variable increase in bulk depends upon the salinity
of the water from which the oyster was previously removed, the
length of time that the floating or washing is continued, and the
character of the water in which they are floated or washed. Shucked
oysters from salt water increase in bulk the same as when in the shell
if soaked in a plentiful supply of fresh water. On the other hand,
plumped oysters, taken from '''brackish water," when placed in
comparatively salt water, will decrease in bulk according to the
saltiness of the water and previous treatment.

In the course of this investigation many localities were visited
where oyster floats were in operation, and in only a very few instances

SOURCES OF CONTAMINATION.

were the sanitary conditions satisfactory. There are hundreds of
oyster floats in. use during the oyster season which are located in
waters of a more or less questionable nature, where the environment
makes contamination possible from one or more of the following
sources: From private or public sewers, privies, house drains, decay-
ing shell heaps, stable yards, chicken yards, dead animals, manure
piles on tilled land, refuse and garbage dumps of cities, etc. Figs.
2 to 10 and the data in Tables 7 and 8 show the facts on which this
statement is based.

The wastes from the oyster boats are usually dumped directly over-
board into the water, which subsequently bathes the growing oysters.
If these boats are numerous it will be seen that the amount of pollu-
tion may be large. It is not a single source of pollution which neces-
sarily condemns the water as being in an unfit sanitary condition,
but it is the sum total of all the sources of contamination which

FIG. 5.— A closer view of the upper oyster floats shown in fig. 4. Note the pile of oysters in the float. Pic-
ture taken at low tide; about two hours later these same oysters were found in the adjoining oyster-
house ready for sale. Oysters drink best at the beginning of flood tide and are "plumpest " about one
or two hours afterwards. The main sewer of the city empties under the bridge above.

gives the bacteriologist his final results. Oyster floats are nearly
always located in sheltered localities (see figs. 2-5), and in such places
the chances for contamination are greatest. The full sweep of the
ocean as it plays over the oyster beds under normal conditions does
not take place so readily where oyster floats are anchored, and thus
this factor of water purification is reduced in efficiency.

It has been proved by observations and experiments made in the
course of this investigation that oysters when floated under the
usual conditions — that is, in water that is only brackish — deteriorate
more rapidly than the same stock unfloated. On this point Nelson48
says that freshening oysters increases very rapidly the rate of weak-
ening and. decay, the life period being reduced one-half. This may
be due in part to the decrease in the salt content of the oyster, which
naturally acts as an antiseptic, or to the increased bacterial content
of the water in which the shellfish are floated.

24 SHELLFISH CONTAMINATION FROM SEWAGE-POLLUTED WATERS.

LABORATORY RESULTS ON FLOATED OYSTERS.

Some results of laboratory experiments on the vitality of B. coli and
B. typhosus in salt solutions of various strength are as follows :

Saturated salt solution (c. p. sodium chlorid) inhibited growth of
B. typhosus after three hours exposure, B. coli and M. aureus after
six hours.

A 25 per cent solution of salt was sufficient to retard development
of the typhoid bacillus, B. coli, and M. aureus in nutrient beef broth.
Growth occurred with lower dilutions.

From the investigations made it appears that oysters grow best to
maturity in water containing from about 1 to 3 per cent sea salt. Above
or below this amount they do not thrive so readily; in fact they perish

FIG. 6. -Oyster floats located near a shucking establishment. The small building in the foreground is a
privy used by 100 to 150 men. The drainage from this vault seeps through the loose soil and wooden wall
into the water which bathes the floats. Drainage from decaying shell heaps and the washings from
these oysterhouses likewise flow into this same water. Analysis of this water and oysters on the floats
showed contamination

when kept for any length of time in waters showing an appreciable
variation from these figures. On this point Nelson,49 of the New
Jersey experiment station, says that the period of viability is greatest
in water having a saline content of about 2 per cent, but for old
oysters the figure is higher. He further says that oystermen should
not be required to freshen oysters, but that this should be done by
the caterer just before cooking.

There seems to be no objection to drinking oysters in waters of the
same saline content as those in which they will grow to maturity,
provided there is no possible source of contamination.

One of the greatest dangers arising from the practice of floating
oysters is the fact that they are often consumed raw, and if polluted,
they become active factors of disease dissemination. As is shown in

SOURCES OF CONTAMINATION.

the quotations from the literature on this subject (page 40), many of
the known epidemics of typhoid fever due to eating infected shellfish
were traceable to those which had become polluted during the process
of drinking. There appears to be no necessit}^ for floating oysters,
and, as practiced at present, it is often exceedingly dangerous to
public health.

The Xew York City Health Department Report on Typhoid Fever"
shows many illustrations of floats located in waters subject to sources
of pollution and the conclusion reached is as follows: "The process
of 'freshening,' 'fattening/ or 'drinking/ often performed as it is in
small streams, badly contaminated with sewage, is a most dangerous
practice and should be discontinued. '' The following data on floated
and unfloated oysters confirm these views:

TABLE 7. — Bacteriological examination of condemned shellfish token from floats located

in polluted waters.

COMPOSITE SAMPLES OF FIVE OYSTERS KACII.

Sample
No.

Bacteria per cubic
centimeter (plain
agar incubated
four days).

B. coli
per cubic
centime-
ter.

Salt.

Remarks.

25° C.

37° C.

•2.'.'.
3

7,000
19,000
12,000

3,000
1,800
1,000

10
10
100

Per cent.

Polluted.
Do.
Badly polluted.

WATER IN REGION OF FLOATS.

7,000

2,500

1,000

0.40

Near sewer above float.

•-'. . .

6,000
4,600

900
200

1
1

1.67
2.06

In channel above float .
In channel opposite floats.

4
5

3,700
1,700

370
200

10
10

1.96
2.10

Over float.
Below floats in channel.

600

180

2.17

Still farther below floats.

These results show that all the samples of shellfish and water taken
from this locality were contaminated. In this case the water con-
tained sufficient salt for the normal growth of oysters, but it was
badly polluted.

TABLE 8. — Bacteriological results on unfloated and floated oysters and on water over floats.

OYSTERS.

Bacteria per cubic
crntiinoter (plain
agar, three days).

B. coli

per cubic

centime-
ter.

Salt.

Remarks.

25° C.

37° C.

VI. (KM)

1,800
5.000

100

Per cent.

Uufloated, 4 out of 5 show gas in 1 ce only.
Floated over night, 3 out of 5 show gas in 0.01 cc of
liquor.

72743° Hull.

26 SHELLFISH CONTAMINATION FROM SEWAGE-POLLUTED WATERS.

TABLE 8. — Bacteriological results on unfloated and floated oysters and on water over

floats — Continued .

WATER.

Bacteria per cubic

centimeter ( plain

B. coli

agar, three days).

per cubic
centime-

Salt.

Remarks.

ter.

25° C.

37° C.

Per cent.

29.000

400

0.59

Lower float, low tide.

2,100

600

.24

Middle float, low tide.

13,000

2.000

.14

Do.

2.000

600

.10

Upper float, beginning flood.

9,000

1.200

.10

Upper float.

420

'110

.84

Mouth of river near oyster beds.

DISCUSSION.

The experiments were conducted on the lower float. The results
of these analyses show the unfloated oysters to be moderately free
from pollution, but when oysters from this same lot were floated over-
night in water proved to be polluted they became dangerously

FIG. 7.— Dumping city refuse to fill a depression within 50 yards of oyster floats. Washings from this
material as well as drainage from piles of manure on fertilized land drain directly into the cove where
oysters are floated.

contaminated. The water taken from the mouth of the river con-
tains less salt than the water over the oyster beds farther out in the
channel, where they grow to maturity. The experiments were made
in a locality where about 500 oyster boats and floats operate at a
distance of one-half to 1 mile above the mouth of the river (figs. 9
and 10). About 60 carloads of shell oysters are shipped daily from
this point during active season. They are all passed through water
of the above character for ll cleansing" and shipped in the shell,
presumably to be consumed raw.

SOURCES OF CONTAMINATION. 27

Field 21 says :

In conclusion it would seem as though the only method to protect the public would
be to forbid the sale of fattened oysters, and to enforce it; also to see that oyster beds
were not subject to contamination from the streams used for sewage purposes, the most
important being the prevention of the process of "fattening" when the water was or
could be contaminated.

The Connecticut State Board of Health 4 says:

The chief damage from oysters, which are an admitted means of conveying certain
infectious diseases, comes from the custom of "floating" or "drinking" them in the
brackish and generally sewage-contaminated waters of rivers and harbors immedi-
ately before they are placed on the market.

There is a widespread belief that the process is actually a fattening one induced by
the fresher water or by the greater abundance of food which often occurs in the places
chosen. Numerous observations have, however, shown that it is not a fattening or a

FIG. 8 —View at low tide showing dead hog covered at high tide by water washing oysters on a float within
150 feet. Wati>r and oysters were found contaminated from the float; the pollution, however, did not all
come from this source.

growing process, as those terms are generally understood. An oyster used as a food
contains no more nutriment after the process than before. It is plumper because it
contains more water, but it is no more fattened by the absorption of the fresher water,
for a day or so than the calf is fattened when induced to drink large quantities of water
just before being sold to the butcher — a process well known to make the animal look
plumper to the eye. Floated oysters are, however, fresher to the taste, and some
persons prefer this taste; others prefer the saltier flavor of those oysters marketed
directly from the saltier waters. It is, however, probable that the floated oysters are
more attractive to the average buyer, whether he be the consumer or the retail dealer.
But the places where the oysters are floated are more liable to sewage pollution than
the localities where they are grown, and hence the danger of the process unless the
streams or harbors when the floating is done are free from sewage pollution. *
The committee again strongly recommends that the "floating" be entirely discon-
tinued, both as a measure for diminishing the typhoid fever and also in the interest of
the oyster-growing industry in this State.

28 SHELLFISH CONTAMINATION FROM SEWAGE-POLLUTED WATERS.

STORAGE OF OYSTERS.

In a report on the " Preservation of fishery products for food,"
Stevenson 65 has shown that the best temperature for cold storage of
oysters is between 38° and 40° F. When stored in good condition
they may be kept at this temperature for six weeks. As an experi-
ment they have been kept for ten weeks, but storage for that length
of time is not advisable.

Some experimental results on keeping shell oysters in this labora-
tory at low temperatures (about 35° F.) showed that they still
remained in good condition after five weeks, but at the end of twelve
weeks nearly all showed from their physical condition alone that
they were unfit for food. When necessary to keep oysters in storage
during the winter they should be kept under good sanitary condi-
tions. Freshly caught oysters are preferable to those which have

FIG. 9.— About 500 boats and as many floats in operation in river. From three to five men operate each
boat, and refuse is generally dumped overboard. Water showed pollution.

aged in the shop. The wet mud on the outside of oyster shells in
piles, when contaminated, may pollute the oysters at the bottom
of the heap by means of infected matter dripping down from the
layers above. Oysters shipped in unclean freight cars may become
contaminated en route, or this may occur during insanitary storage
in bins at oyster houses.

SPOILAGE DUE TO LENGTH OF TIME OTJT OF WATER.

Stale oysters are without question a dangerous article of food.
This kind of material has undoubtedly produced serious gastro-
intestinal disturbances and possibly death when consumed by indi-

SOURCES OF CONTAMINATION.

viduals susceptible to ptomain poisoning. In fact any highly per-
ishable food product of this character may quickly spoil and be
injurious to health if not properly refrigerated under good sanitary
conditions. As just stated, oysters may be kept for a period of six
weeks under proper conditions, yet, even though they were taken
from unpolluted beds and stored under good sanitary conditions,
mere length of time alone may cause them to become unfit for use.
No oyster should be used when the shells show the least gaping, nor
when the liquor is practically all gone.

DISEASED AND GREEN OYSTERS.

In their study of the " Oyster and disease," Herdman and Boyce 28
elaborately treat the subject of green oysters. They show that cer-

YIG. 10.— Oyster floats between the row ol oyster 1 >oats (fig. 9) and the shore. Anchored from piles. Both
oysters and water from this locality were found to be contaminated. Sixty carloads of oysters, mostly
eaten raw, are shipped from this place daily in winter. Beds on which they grow arc probably uncon-

taminated.

tain of the green oysters are healthy, while others are not so consid-
ered. Some forms of greenness are described as a "leucocytosis,"
which may be associated with an excessive amount of copper. Other
species may have no copper present^ but a special pigment, uma-
rennin," is found with a certain amount of iron. In the present in-
vestigations the green oyster was frequently encountered and
a mounts of copper varying from 150 to 714 mg per kilogram a were
found, while from oysters not showing the green coloration amounts
varying from 14 to 40 mg per kilogram were obtained. Apprecia-
ble quantities of copper were also found in the water and mud b taken

a Analysis made by W. C. Taber, Food' Inspection laboratory.

b Analysis made by W. W. Skinner, Water Laboratory, Miscellaneous Division.

30 SHELLFISH CONTAMINATION FROM SEWAGE-POLLUTED WATERS.

from the localities where the green oysters had grown. It was
demonstrated that the copper contamination undoubtedly came
from smelter factories loca'ted on the water front, from which the
wastes and effluent drained into the harbor bathing the oyster grounds.
The oysters showing the highest amount of copper were collected
nearest the factories, and they possessed a distinctly metallic taste.
This subject is receiving further study in the Bureau of Chemistry.
It is said that certain European varieties of green oysters are
cultivated as a luxury and sold at a premium because of their color.
Oysters may die from sewage wastes in badly contaminated waters.
In one locality it has been estimated that four out of five oysters on
certain beds were destroyed from this condition of affairs during
one season.

HANDLING OF SHUCKED OYSTERS..

The initial pollution of shucked oysters may be due to the shell
stock being taken from sewage-polluted grounds, but in the liquor
surrounding the meat and in the intestinal contents of all shellfish
there are some bacteria. When the kind of bacteria are such as nor-
mally occur in unpolluted sea water, and are present in small numbers,
they are considered harmless and their presence is disregarded. On
the other hand, when B. coli and similar forms of germ life represent-
ing the presence of sewage matter are found the bacteriologist is forced
to take a different view of the matter. The B. coli group of organisms
may be present in numbers not sufficient to condemn the oysters when
fresh, yet when shucked and allowed to stand improperly iced under
bad sanitary conditions these few organisms may multiply and pro-
duce millions before the oysters are consumed. While it is essential
that oyster beds should be free from pollution in order to be assured
that the shucked stock has not been contaminated from this source,
dirty methods of shucking alone may account for contamination.
Oysters grown on soft muddy bottoms are generally covered with a
coating of mud, and unless this is removed from the shell before shuck-
ing some of the mud is likely to get into the opened stock. The oys-
termen claim that this is one of the reasons for floating oysters. If it
were done for this purpose alone, in pure water of the proper salt
content, there would be no objection to the process; in fact it would
be beneficial, in that it would allow the oyster to free itself of the sand
and grit contained within the gills and at the same time cleanse the
outside of the shell.

The following results illustrate the relative bacterial content of
shell and market-shucked oysters:

SOURCES OF CONTAMINATION.

TABLJ-: '.'.

<>!' l><i<-t< rial <-<nit</t/ <>f .s//r// t-huns dud oy sters with shucked run i hi t
oysters.

Data determined.

36 miscel-
laneous

S;U1I|)1»-S of

shell oys-
ters.

20 samples
of hard-
shell
clams, a

33 samples
of shucked
market
oysters.

: i per cubic centimeter after 4 days:
A \ crage —
I'l-iin agar 25° C

6,000
1,000
200
26,000
150

7+
100
0

275,000
18,000
3,000
4.300,000
2,000

180
1,000
0

M,T mm
268,000
45,000
4.7.50.000
15,000

74.000
1,000,000
0

I'l-iin 'far 37° C

Bile salt agar 37 ° C

M ixiinum (95° C )

Minimum ( ''5° C )

B. coll:
\ \ rrujre .

Maximum -

« Many of these clams were from badly contaminated waters.

From the results given in the table it is seen that these 33 samples
of shucked oysters, probably representing fairly those ordinarily
found in markets and retail stores, have greatly increased their bac-
terial content. This increase is largely due to negligence and unclean
methods of handling.

Various opening methods are employed by oyster shuckers in
different localities. The hands of the average opener are generally
unclean, and the proper facilities for keeping them in a better condi-
tion are lacking in most establishments. In nearly every method
employed the dirty hand of the shucker comes in contact with the
opened oyster while transferring it from the shell to the bucket.
Oystermen should keep their hands out of the cans of shucked oysters,
especially after they are wrashed and prepared in containers ready for
market. The average man's hands are unclean from a bacterio-
logical point of view. A few colon organisms introduced in this way
may result in the condemnation of goods shipped for a long distance,
or they may spoil, and the colon bacilli unduly increase if allowed to
stand some time before consumption under conditions favorable to
rapid bacterial growth. Marked improvement must be made in the
present manner of opening oysters before they will be satisfactory
from a sanitary point of view. Washing the oyster shells, cleansing
the hands from time to time, and bringing only the knife in contact
with the oyster when transferring the oyster from the shell to the
bucket would contribute to more sanitary results.

INSANITARY OYSTERHOTJSES.

The average oysterhousc is not sanitary either in its construction
or in its maintenance. Buildings of wood, with inadequate venti-
lating and lighting facilities, wooden floors, ceilings and walls
covered with cobwebs, and accumulated dust are the conditions
generally found in making inspections of these places. The modern

32 SHELLFISH CONTAMINATION FROM SEWAGE-POLLUTED WATERS.

FIG. 11.— Shucking oysters. Each man stands at a stall where the oysters are opened and put into small
buckets. General sanitary conditions very bad. In this place there were numerous long cobwebs
dangling from the ceiling, with dust and filth everywhere noticeable.

food factory is not only built of fireproof material, but is carefully
arranged as regards ventilation, toilet facilities, proper location,
drainage, etc. Concrete floors and walls can be flushed daily with
water, and with the installation of these and other sanitary measures
there is no reason why any oysterhouse could not be kept in a clean,
wholesome condition. Oysters from pure beds could hardly escape
pollution \)y the time they had passed through an unclean oyster
establishment. Aside from insanitary premises, the question of
securing workmen who are cleanly is one of the practical difficulties

FIG. 12.— Another shucking establishment showing insanitary conditions.

SOURCES OF CONTAMINATION.

with which the oystermen have to contend. Regulations should be
enforced requiring better care of the hands and more personal clean-
liness in general on the part of oyster shuckers. To this end, the
necessary toilet facilities should be provided for their welfare and
comfort.

Bacteriological tests made by exposing freshly prepared agar plates
4 inches in diameter where oysters were being shucked show the rela-
tive bacterial content of the air in such places. One set of such
experiments gave the following figures:

A one-minute exposure resulted in the growth of 130 colonies;
two minutes, 180 colonies; three minutes, 220; four minutes, 350;
and five minutes, 430 colonies. The organisms consisted of molds,
yeasts, spore-bearing and various chromogenic and other colonies.

FIG. 13.— (/lam diggers' huts,

hucking is (lone. Sanitary conditions on the interior generally very
unsatisfactory.

Is it strange that under such conditions the oystermen have difficulty
in keeping opened oysters, especially when tubs and containers are
not covered? Contrast these results with a similar set of plates
exposed in the bottling room of a clean dairy where sanitary condi-
tions obtained: One-minute exposure, 9 colonies; two minutes, 15
colonies; three minutes, 20; four minutes, 2ft; and five minutes, 30
colonies.

WASHING OYSTERS.

It is essential that both the water and ice used in washing and
cooling shucked oysters should be free from pollution. Natural ice
harvested from polluted sources should not be used for this purpose,
and even artificial ice may become contaminated by careless handling.
A number of samples of water used for washing oysters were exam-

34 SHELLFISH CONTAMINATION FROM SEWAGE-POLLUTED WATERS.

ined, and some proved to be satisfactory, while others were unfit for
such purposes. The bacteriological condition of water can only be
determined by making the necessary examinations. Most large
cities have records of the bacterial content of their water supply, and
if such waters were being used for washing shellfish the oystermen
could inform themselves as to its purity from the records of the city
health office.

That the liquor bathing the meat of the oyster contains more
bacteria per given volume than does an equal volume of minced
oyster meat is shown in Tables 10 and 11. A brief, brisk washing,
not to exceed 3 or 5 minutes in duration, is usually sufficient to
remove this liquor, and also the adhering sand and grit which may
be clinging to the gills of the oyster. It is not necessary to soak
oysters over night in order to wash them. Soaked oysters, like
floated oysters, deteriorate more rapidly than do those which have
not been so treated. Oysters may be washed two or three times
before finally reaching the consumer. The total length of all the
combined washings should not exceed 30 minutes, and pure iced
water should be used. The efficiency of any washing device or
method depends largely on its mechanical points, and the amount
of soakage taking place will vary with the manner of washing, the
relative quantity of oysters and water used, and the temperature
of the wash water.

Tables 10 and 11 illustrate the relative bacterial content of the meat
and liquor of shellfish, Table 1 1 being considered with special refer-
ence to the development in plain and in saltless agar.

TABLE 10. — Bacterial content of oyster meat and oyster liquor compared.

Oyster meats.

Oyster liquor.

Bacteria per cubic
centimeter after

Sample

four days' incuba-
tion.

B. coli
per cubic

four days' incu-
bation.

B. coli
per cubic

Plain agar
at 25° C.

Bile salt
agar at
37° C.

meter.

Plain agar
at 25° C.

Bile salt
agar at
37° C.

meter.

1...

2,800,

55,000

34,000

10,900*

13,500

1,200

3 700

93 600

1,200

4,200

5 .

2 000

3 800

300

7,500

44 000

7...

2,000

7 500

Approxi-

mate

aver-

age....

4,300

0.7

31,000

7,120

5.9

The results show that the oyster liquor in these samples contained
more than seven times as many organisms per given volume as did

SOURCES OF CONTAMINATION.

the minced meat and body contents of the same oysters. The results
further show that the liquor contained eight tunes as many B. coli
per cubic centimeter as the minced meat.

TABLE 11. — The relative number of organisms in oyster and clam meat and liquor samples
on plain nutrient and on saltless agar at 25° and 37° C.

Sample
No.

Description of sample.

Organisms per cubic centimeter after
four days' incubation.

Approximate aver-
age.

Plain agar
25° C.

Saltless
agar 25° C.

Plain agar
37° C

Saltless
agar 37° C.

25° C.

37° C.

I...

Oyster meat

23,000
230,000

70,000
150,000

7,000
21,000

110,000
180,000

12,000
190,000

41,000
60,000

1,000
6,000

100,000
170,000

7,000
60,000

26,000
70,000

3,000
2,000

20,000
70,000

21,000
43,000

13,000
14,000

1,000
3,000

11,000
85,000

17,500
210,000

55,500
105,000

4,000
13,500

105.000
175,000

14,000
51,500

19,500
42,000

2,000
2,500

15,500
77,500

Oyster liquor

Oyster meat

4
5

Oyster liquor

Clam meat

Clam liquor

7...
g

Clam meat

Clam liquor

Approximate average

99,000

72,500

32,000

• 24,000

85,700

28,000

Approximate average of oyster meat at both temperatures 26,000 organisms per cubic centimeter.

Approximate average of oyster liquor at both temperatures 102,000 organisms per cubic centimeter.

Approximate average of clam meat at both temperatures 31, 000 organisms per cubic centimeter.

Approximate average of clam liquor at both temperatures 67, 000 organisms per cubic centimeter.

The general averages show nearly three times as many organisms
per given volume for the liquor of oysters and of clams as for the
same volume of meat substance. This explains the fact claimed by
practical oystermen that the liquor spoils before the meat of shellfish.

CHARACTER OF CONTAINERS.

The proper cleansing and sterilization of utensils and containers is
essential to insure freedom from contamination. Single-shipment
cans properly handled are less liable to harbor objectionable bacteria
than are those packages used for more than one shipment; however,
there is no objection to using the latter if they are free from bacteria.
Cans are often returned to the shipper in very bad condition, and
unless well scrubbed and sterilized they may become a source of
danger. By the use of single-shipment packages and a plentiful
supply of boiling water there should be no difficulty experienced
from unclean vessels. After cleansing and sterilization cans should
be inverted or otherwise protected against the entrance of dust,
which nullifies the good done by sterilization.

Progressive oystermen now agree that the best method of shipping
oysters is in sealed packages with no ice in contact with the goods.
This method prevents contamination from impure ice and protects
the oysters in a better manner during shipment than did the old
style of tub with ice in contact. The series of shipping experiments
made fully demonstrated the superiority of the more modern
method.

36 SHELLFISH CONTAMINATION FROM SEWAGE-POLLUTED WATERS.

INSUFFICIENT COOLING.

The proper cooling and subsequent refrigeration of any perishable
food product is highly essential to prevent rapid decay from bacterial
activity. The results obtained in a series of experiments on the keep-
ing qualities of oysters demonstrate that the proper refrigeration of
shucked oysters is necessary to retard deterioration. Even when
such oysters are kept at low temperatures above the freezing point
there is some bacterial development taking place, but this is reduced
to the minimum by a plentiful supply of ice.

SOURING DUE TO AGE.

The souring of oysters may occur because of the length of time
they are allowed to stand after shucking. Such oysters may have

FIG. 14. — Various types of containers for shipping oysters, as used by the trade.

contained but few organisms originally when freshly opened, but
because of age alone they become unfit for use. There are always
enough bacteria present in oysters even when opened under the best
of sanitary conditions to cause spoilage after a certain interval of
standing. This length of time will depend upon the number and kind
of bacteria present and the temperature at which the oysters are
stored. This fact is well illustrated in fig. 15, showing the results of
two methods of keeping opened oysters.

Shucked oysters are best when freshly opened, and they should be
consumed at the earliest possible moment after shucking, although
oysters grown on sanitary beds and handled under proper conditions
remain edible for several weeks, when unshucked, but their quality
does not improve with the length of time out of the shell. Illness
of a serious nature may result from eating stale shellfish.

COOKING TESTS.

GRAPHIC PRESENTATION OF RESULTS BY TWO METHODS OF HANDLING.

The graphic chart shown in fig. 15 is a striking illustration of the
widely differing results obtained by two different methods of handling
the same oysters. Fourteen gallons of oysters from the same lot of
shell stock were shucked by the same man, under identical condi-
tions, washed for from three to five minutes in ice water having 16
bacteria per cubic centimeter, divided into two lots, and handled as
follows : One lot was placed in uncovered cans with ice in contact and
handled in the usual manner by the oysterman on whose premises the
work was done, while the other lot was put in clean covered cans and
placed in the ice box surrounded by cracked ice which was not in con-
tact with the oysters. The results given in fig. 15 show that the

FIG. 15.— Comparison of results obtained by handling the same lot of oysters in two ways. Plotted results
are averages of duplicate samples plated on plain agar at 25° C. and on plam agar and bile salt agar at
37° C., for three days.

oysters when kept clean and cold did not decompose or sour within
the period of observation, while those not thus treated quickly spoiled
and were soon unfit for food.

It subsequently developed that the oysters used were taken from
polluted beds, thus partly accounting for the high B. coli content, but
in spite of this fact the oysters kept under good sanitary conditions
showed no appreciable change after five days' storage. Had good
oysters been used in the beginning even better results would have
been obtained. As it was, even with 10,000 B. coli present per cubic
centimeter practically no increase took place in the organisms pres-
ent in the oysters kept in the ice box, while in the other lot they
increased to 100,000 per cubic centimeter in five days.

COOKING TESTS.

Five sets of experiments were conducted to demonstrate the value
of cooking oysters and clams and the time required to destroy the
organisms present by heat. All of the tests were made by exposing
the shellfish to live steam (98° to 99° C.) in a steam sterilizer for
periods varying from 2 to 30 minutes. About 1 quart of oysters

38 SHELLFISH CONTAMINATION FROM SEWAGE-POLLUTED WATERS.

in an Erlenmeyer flask was used for each of the tests on shucked
oysters, while about 3 dozen medium-sized oysters and hard
clams in the shell were laid on the shelves of the sterilizer for the
other experiments. The steamer was full of live steam when the
samples were introduced. Tables Nos. 12 to 15, inclusive, show the
results of these tests.

TABLE 12. — The destruction, by steaming, of bacteria in shucked oysters artificially infected

with B. coli.

Sample.

Time of
cooking.

Organisms
per cubic
centimeter

four days,
at 25° C.).

Per cent gas in dextrose fermentation tubes (four days,
at 37° C.).

Per cent
killed.

O.lcc

0.01 cc

0.001 CC

0.0001 cc

0.00001 cc

0.000001 cc

Minutes.
Uncooked.
5
10
15
20
25
30

80,000,000
725,000
20,500
170
100
65
0

35
40
40

0
0
0

35
45
45
0
0
0
0

30
45
35
0
0
0
0

40
0
40
0
0
0
0

40
0
0
0
0
0
0

0.00
99.09
99.90
99.99+
99.99+
99.99+
100.00

45
45
0
0
0
0

These results show that all B. coli were destroyed during from 10 to
15 minutes' exposure to live steam. In the following experiment on
steaming shucked oysters, naturally infected, all B. coli types failed
to develop when exposed to live steam for from 5 to 10 minutes.

TABLE 13. — Bacteriological results showing effect of steaming shucked oysters naturally

infected.

Sample
No.

Time of
cooking.

Bacteria
per cubic
centimeter

at 25° C.
for three
days).

Per cent gas in dextrose
three days, at 37° C.

Per cent
killed.

Remarks.

0.5 cc

O.lcc

0.01 cc

Minutes.
Uncooked.
5

10
15
20
25
30

716,000
13,000

10
10
9
5

35*
50

0
0
0
0
0

20
0

0
0
0
0
0

0
0

0
0
0
0
0

0.00
98. 10+

99.99+
99.99+
99.99+
99.99+
99.99+

Variety of colonies on plates.
Less variety of colonies on
plates.
Both colonies spore bearing.
Spore-bearing colonies on plates.
Do.
Do.
Do.

3
4

5
6

TABLE 14. — Bacteriological results showing the effect of steaming oysters in the shell.

Sample
No

Time of
cooking.

Bacteria
per cubic
centimeter
(plain agar
at 25° C.
for four
days).

Per cent gas in dextrose
four days at 37° C.

Per cent
killed.

Remarks.

O.lcc

0.01 cc

0.001 cc

I...

Minutes.
Uncooked.
5

10
15
20
25
30

15,000
6,700

270
250
40
20
20

0
0
0
0
0

5
0

0
0
0
0
0

0
0

0
0
0
0
0

0.00
55.33

98.20
98.33
99.73
99.80
99.80

Variety of colonies on plates.
Less variety of colonies on
plates.
Colonies largely spore bearing.
Colonies all spore bearing.
Do.
Do.
Do.

3
4
5

COOKING TESTS.

These results show that in this instance all gas-producing organ-
isms were destroyed by from 5 to 10 minutes' exposure to live steam.
In Table 15 a similar experiment on hard clams in the shell shows
that gas-producing organisms survived and were recovered in 5 cc
quantities of liquor from clams exposed 20 minutes to live steam.
After 5 minutes' exposure, however, 91.11 per cent of the total organ-
isms were killed. The dense shells of hard clams may account for
this delayed destruction of bacteria.

TABLE 15. — Bacteriological results showing the effect of steaming qaahaags (hard clams)
in the shell for varying periods.

Organisms
per cubic

Per cent gas in dextrose five days
at 37° C.

No.

Time of
cooking.

centimeter
(plain agar
at 25° C.

Per
cent
killed.

Remarks.

tor five

5cc

Ice

0.5 cc

0.1 CC

0.01 cc

days).

Series A :«

Minutes.

1. ...

4,500

0.00

Variety of colonies.

2. ...

400

91.11

Do.

3. .
4.
5.

»i.

10
15
20
25

200
60
40
30

50
60
20
0

0
0

0
0
0
0

95.60
98.67
99.12
99.34

Less variety of colonies.
Largely spore bearing.
Spore-bearing colonies.
Do.

99.56

Do.

Series 3

106,000

.00

53,000

50.00

2,400

97.73

2,000

98.20

1,500

98.70

1,000

99.06

a Thirty clams were exposed to live steam in a sterilizer and five were removed for each sample at inter-
vals of five minutes.

These results indicate that 2 minutes' exposure to live steam
destroys 50 per cent of the bacteria, but B. coli types remained after
10 minutes' exposure, although these germs failed to grow in the sam-
ple consisting of five clams removed after 8 minutes' exposure. It
appears from these experiments that at least 10 or 15 minutes are
required to destroy B. coli in small quantities of ordinary market
oysters and clams; therefore, the usual methods of cooking shellfish
will not remove the danger of infection from disease-producing
organisms should they be present. When larger quantities of
shellfish are cooked* at one time in the same container a sufficient
temperature may not be reached within the interior of the mass to
destroy the germs thus protected from the action of the heat. In
such cases it would be advisable to maintain a high temperature
for a longer time. Herdman and Boyce41 say:

Shellfish must not be taken as a food from grounds where there is any possibility
of sewage contamination; after removal from the sea, while in transit, in store, or in
market, they should be carefully 'protected from any possibility of insanitary environ,
ment; they should not be kept longer than is absolutely necessary in shops, cellars,
etc., in towns, where even if not running the risk of fresh contamination they are under
conditions favorable to the reduction of their vitality and growth of their bacterial
contents; the fresher they are from the sea the more healthy they are likely to be;
finally, only absolutely fresh shellfish should be eaten uncooked, and those that are
cooked must be sufficiently cooked, raised to boiling point and kept there for at least
10 minutes.

40 SHELLFISH CONTAMINATION FROM SEWAGE-POLLUTED WATERS.

COLLATED OPINIONS ON SEWAGE CONTAMINATION.

TRANSMISSION OF DISEASE BY INFECTED SHELLFISH.

Many workers in this country and in Europe have shown by their
researches that shellfish may become contaminated from polluted
waters and that serious consequences follow ingestion of such food
when consumed uncooked. In this connection it is a noteworthy
fact that many of the recorded epidemics of typhoid fever arising
from consuming infected shellfish were from oysters which had been
subjected to the process of "floating" or " drinking" before being
offered for sale.

In his report on shellfish pollution, Fuller 25 credits Dr. Pasquier?
a French physician, in 1816, as having first reported an epidemic of
typhoid fever due to eating oysters which had been laid down in an
old citadel where sewage had been discharged for centuries. Fuller
cites other cases as follows :

In Great Britain during the cholera epidemic in 1849 an outbreak of this disease
occurred which was considered due to the consumption of condemned oysters; they
were, nevertheless, given to school children.

All the members of a supper party of seven at Truro, England (1897), became ill
either from typhoid or gastroenteritis due to eating oysters taken from a source
known to be polluted.

At St. Andre de Sangonis, France, Dr. Chantemesse reported 14 cases of typhoid
and gastroenteritis from six families who ate sewage-polluted oysters.

From 1894 to 1902, Dr. Newsholme, Brighton, England, investigated 643 cases of
typhoid fever. He found 158 cases directly ascribable to the consumption of oysters
from sources subsequently proven to be polluted.

At Manchester, England, from 1897 to 1902, Dr. Niven ascribed 118 cases from a
total of 2,664 cases of typhoid to oysters and mussels, and 156 more cases were asso-
ciated with the consumption of other shellfish .

The Atlantic City epidemic of typhoid during the summer of 1902 was traceable
to oysters and clams "freshened" in sewage-polluted waters.

The investigations of Dr. Soper in 1904 showed that two-thirds of 31 cases of typhoid
reported at Lawrence, L. I., were traceable to shellfish taken from polluted sources.

One of the most important and widely known outbreaks of typhoid
in recent years due to eating infected oysters occurred at the Wes-
leyan University, October 12, 1894, at Middletown, Conn. The evi-
dence presented by Professor Conn15 in his report on this out-
break showed most conclusively that the 23 cases of typhoid which
appeared among the 100 students and guests at their fraternity
banquets were due to eating infected oysters which had been "fat-
tened" within 300 feet of the outlets of private sewers. He concludes
his report by saying :

Doubtless many cases of mysterious typhoid have been due to such a cause. To
trace these is a matter of extreme difficulty. The peculiar conditions which have
occurred here have been such, however, as to bring the matter into clear light, and
to throw with certainty blame of typhoid distribution upon a source which has for
some time been suspected, but not demonstrated. That the practice of fattening

OPINIONS ON SEWAGE CONTAMINATION. 41

oysters in the mouths of rivers in the vicinity of sewers is dangerous to the public
health is beyond question shown by I lie combination of conditions which have made
it possible to trace the \Yeslcyun typhoid outbreak to the eating of a lot of infected
raw oysters.

In reporting the typhoid epidemics of the mayoralty banquets at
Winchester and Southampton, England, November 10, 1902, Dr.
Bulstrode11 cites 21 cases of typhoid and 118 cases of gastroenteritis
from a total number of 267 guests who ate raw oysters. The oysters
in question were imported from France and "laid down" for a few
days in sewage-polluted "drinking" grounds at Emsworth. One
patient who developed a fatal case of typhoid only ate one infected
oyster, while certain of the guests ate only two of their three oysters.

The health officials of New York City,51 in making a study of 1,786
cases of typhoid fever reported during 1904, in the Borough of Man-
hattan, obtained data on 1,322 cases. Of this number 22 cases, or
1.6 per cent, were habitual consumers of raw oysters, while 44 cases,
or 3.3 per cent, habitually consumed both raw oysters and raw milk.

Dr. Fraser,22 in speaking of the public health of Portsmouth,
England, for 1907, where there was reported 233 cases of typhoid
fever, says:

The one article of diet which in this town has a special relationship to typhoid
fever is shellfish, and during last year no fewer than 80 persons, or 34 per cent of the
total number attacked, contracted typhoid from this source. * * *

It seems that the only thing that can be depended upon to stop this loss of life is
legislation, making it illegal to collect shellfish from any places certified by local
medical officers to'be subject to sewage pollution. Otherwise men are sure to collect
and hawk the fish from such places, and the public purchases them not knowing, nor
apparently caring, what their previous history has been.

In summarizing his work on shellfish pollution Fuller 25 concludes
by saying:

There are those who still believe that polluted shellfish cut very little figure, gen-
erally speaking, as regards the public health. Some of these persons appear to have
formulated their views without knowledge as to general experiences or the evidence
upon the subject. Others for commercial reasons attempt to minimize the evidence,
and class it as a whole with some statements and conclusions which are obviously of
questionable accuracy. There has been a substantial harmony in the conclusions
reached by all who have investigated the subject carefully.

The evidence already presented leaves no room for reasonable doubt that to a lim-
ited degree typhoid fever is transmitted by oysters, clams, and some other shellfish
which become infected in sewage-polluted waters.

While scientific or medical literature contains little or no evidence
to disprove the theory of disease transmission through the agency
of infected sea food, it is true that sometimes disease and death are
attributed to this source without just cause. For example, in April,
1908, there appeared in many of the New York papers notices of
death from typhoid occurring in a family named Bendt residing in
Newark, N. J., and the infection was attributed to eating bad oysters.
The Department of Public Health of Newark, N. J., stated that the

42 SHELLFISH CONTAMINATION FROM SEWAGE-POLLUTED WATERS.

report was absolutely false and the death certificate gave the cause
as " cerebrospinal fever." Further inquiry by the food inspector
into these cases showed that the victims had not eaten oysters at all.
Such reports as these, containing not the least foundation of truth,
undoubtedly inflict an undeserved hardship upon an industry of
much importance, and every precaution should be taken to substan-
tiate such statements before they are made public.

PRESENCE OF BACILLUS COLI AND BACILLUS TYPHOSUS IN OYSTERS.

The present investigations disclose no reason, biological, anatom-
ical, or otherwise, why oysters and other shellfish can not become
contaminated when exposed to sewage-polluted waters, and the
following references upheld the conclusion that this occurs.

Klein38 reports: "Bacillus coli (typical) was found in 5 out of 8
cockles." Houston33 concludes his report on the bacteriological
examination of deep-sea oysters by saying: "The results show that
in deep-sea oysters derived from deep-sea water, remote from sewage
pollution, B. coli and coZi-like microbes and also the spores of B.
enteritidis sporogenes are either absent or, at all events, seldom
detectable. The same is true of surface water over such oysters."

Smith 62 found B. coli, B. enteritidis sporogenes, and streptococci in
fluid from shellfish grown on grounds suspected to be polluted, but
failed to find these germs from areas free from sewage.

Hewlett30 says: "From my observations I have no hesitation,
therefore, in concluding that oysters from water uncontaminated with
sewage do not normally contain the colon or allied bacilli or the
Bacillus enteritidis sporogenes." He examined 32 oysters from dif-
ferent sources, and, with the exception of 2, not one of them con-
tained B. coli or B. enteritidis sporogenes.

In making an examination of Charles River clams, Dr. Hill 32 says :

These clams contain within their intestines at least three species of bacteria char-
acteristic of sewage. These organisms were not found in the intestines of clams or
oysters from less contaminated or uncontaminated waters. The general proposition
is accepted, therefore, that food which may be eaten raw should never be exposed
to untreated sewage containing the typhoid bacillus nor to uninfected sewage unless
the food is of such a character that it can be thoroughly cleansed before it is eaten.

Beale 2 in his work on clams says :

The results of this examination proved that the clams were grossly polluted with
sewage, inasmuch as the B. coli communis could be detected in ^fa and the B. enteri-
tidis sporogenes in -^ part of the clam. It is especially noteworthy that even after
boiling 15 minutes the Bacillus communis could be recovered from the bodies of the
clams.

Ewart 19 concludes that mussels can be obtained free from all evi-
dence of sewage pollution, and states further —

That the number of Bacillus coli found in the mussels corresponds closely to the
environment, hence the mussel can not be regarded as a filter accumulating harmful
organisms. * * *

OPINIONS ON SEWAGE CONTAMINATION. 43

That broadly speaking, a fall in the ratio between organisms growing at 20° C. and
those at 37° 0. corresponds with sewage pollution. The same may be said with
regard to spore-bearing forms.

After completing their investigations, the Virginia State Board of
Health 69 reports : ' ' We conclude that the colon bacillus is not found
as a normal inhabitant of the oyster, either of the natural fluid of the
shell nor of the intestine."

Every one of 34 samples of deep unpolluted sea water, according
to Houston,33 failed to show the presence of B. coli or coZi-like organ-
isms in quantities as large as 100 cc of the sample.

Evidence is produced from Fuller's 25 report showing that fish from
unpolluted water do not harbor the colon bacillus, while to the con-
trary where water is known to be contaminated this bacillus is found
in the intestines of fish. The influence ol birds, boats, and shore-
line railroads is also discussed in this report, which concludes as
follows: " Generally speaking we may say that deep sea water dis-
tant from local sources is unpolluted according to Bacillus coli
tests."

Dr. Soper,63 in reporting the Lawrence, Long Island, outbreak,
found that while 20 per cent of oysters were certainly polluted on
the inside, as many as 70 per cent were polluted on the outside.
Dr. Savage59 says that "mud samples yield more reliable bacterio-
logical evidence of the degree of contamination of a tidal river than
either water or oyster samples. Muds which show high relative
purity are safe for oysters."

Professor Huxley is quoted as saying in the report of the Royal
Commission on Sewage Disposal :

I do not see how it can be doubted that oysters taken from a bed irrigated with
sewage and eaten uncooked would be dangerous articles of diet. Does anybody
pretend that it would be safe to take drinking water (unfiltered and otherwise unpu-
rified) from a body ot fresh water, of similar dimensions to any estuary which may
be under consideration, at a point equally near a sewage discharge? li such a pro-
ceeding is safe, our sanitary authorities are taking a great deal of trouble in vain;
if it is not safe neither is it desirable to eat oysters the iuices of which are impregnated
with sewage in however dilute a condition.

This commission further recommends that each Government should
require a guarantee that all oysters or other shellfish imported into
thjeir country for human consumption had been procured from locali-
ties where they were not liable to contamination by sewage or other
objectionable filth.

In their work on the study of shellfish Clark and Gage 14 state:

Enough study has been made by many investigators to show that B. coli is not a
normal inhabitant of the intestines of clams or oysters, and that its presence in the
intestines or juice in the shell must be due to contamination, either by drainage and
sewage flowing over the clam and oyster beds, or by careless and uncleanly handling
of the shellfish between the time of collecting and placing upon the market. In this

44 SHELLFISH CONTAMINATION FROM SEWAGE-POLLUTED WATERS.

work, therefore, the ability to demonstrate clearly the presence of a specific sewage
organism such as B. coli is an invaluable aid in determining the question of purity or
pollution."

Fuller 23 concludes his work on oysters from the .N arragansett Bay
by saying :

The results obtained in these experiments indicate that B. coli is not normally
found in sea water or in common edible shellfish, and that the presence ot this organism
in oysters, clams, mussels, and similar shellfish is an indication of sewage pollution.

VITALITY OF BACILLUS COLI AND BACILLUS TYPHOSUS IN SEWAGE-
POLLUTED WATER AND IN SHELLFISH.

The results obtained by different investigators on this point vary
somewhat according to the conditions under which the experiments
were conducted: the vital fact, however, is that B. coli, B. typhosus,
and other organisms do survive sufficiently long, under favorable
conditions, in sewage-polluted waters to transmit disease when such
water is consumed, whether directly, or indirectly by such a medium
as shellfish.

Savage 59 says :

Owing to the enormous difficulties inherent to the isolation of the typhoid bacillus
from bacteriologically complex substances such as highly polluted tidal mud it would
be rash to draw sweeping deductions from negative results, but * * * it seems
justifiable to infer that typhoid bacilli can survive in polluted muds for at least two
weeks, and this fairly readily, but that after about two weeks they may rapidly de-
crease, although they may, and probably do, persist under favorable conditions for
some little longer, but in vastly diminished numbers. Experiment (3) seems to
definitely show that they may survive for at least three weeks.

McNaught 42 concludes that "the duration of life of B. coli in
unsterilized water varied greatly in waters from different sources.
The purer the water the longer did B. coli survive in it." He further
says:

In unsterilized sewage B. coli only survived for three weeks, while it survived over
eight months in the same sewage sterilized. After six months' growth in sterilized
water and eight months' growth in sterilized sewage B. coli retained all its original
characters except that possibly its power of indol production was weakened.

The Lancet,37 in reviewing some experiments and observations
on the vitality of B. typliosus in oysters made by Klein, says:

The actual results detailed in the report, though valuable, are not particularly novel.
They definitely settle the question as to whether the Bacillus typhosus will live in the
oysters. It is demonstrated that there is destruction of the Bacillus typhosus both in
the body of the oyster and in sea water; that an oyster infected with large numbers of
typhoid bacilli " cleans" itself in about from 9 to 12 days when placed in clean water
which is frequently changed; and that oysters kept in the dry state, though capable
of destroying the bacillus, yet remain polluted for a much longer period than oysters
placed in constantly changed clean water.

The investigations of Dr. Buchan 10 show that typhoid bacilli sur-
vived in mussels for at least 26 days where the organisms were found
abundantly; he concludes by saying: "This experiment emphasizes

OPINIONS ON SEWAGE CONTAMINATION. 45

the need of protecting mussel layings from all possibility of sewage
contamination."

Herdman and Boyce 28 found that 14 days was about the average
duration of the life of the typhoid bacillus in sea water incubated
at 35° C.; when kept in the cola, their presence was demonstrated
on the twenty-first day. They further state:

The bacillus probably does perish in a short time in the sea, just as it does in sea
water in the laboratory, but we have no evidence before us to show how it is so in the
case of the mud upon which the oysters may be laid; hence it is possible that the
bacillus might be capable of a saprophytic existence.

In our experiments, in washing infected oysters in a stream of clean sea water the
results were definite and uniform; there was great diminution or total disappearance
of the typhoid bacilli in from one to seven days.

Martin 43 shows that typhoid bacilli survive for at least 12 days in
unsterilized soils when kept in a moderately dry condition at a tem-
perature ranging from 2° C. to 12° C.

Klein39 states: "At the end of three weeks, a sample from the
Bacillus coli sewage flask still yielded on culture innumerable colo-
nies, whereas a sample from the flask inoculated with the typhoid
bacillus yielded 12 colonies."

Houston 34 in a recent report shows that 99 per cent of the typhoid
bacilli added to water died within one week. In a majority of the
experiments, however, a few typhoid bacilli remained alive for one or
two months.

The results obtained in this laboratory on the vitality of B. coli in
unsterilized, but practically sterile, spring water at room and ice-box
temperature showed that this organism survived only for about one
month at room temperature, but remained alive after two and a half
months at ice-box temperature (about 15° C.). The experiment was
conducted by inoculating quart bottles of a high grade unsterilized
spring water containing practically no organisms with 0.1 cc of a
24-hour bouillon culture and pouring plates at frequent intervals.
The bottles during this time were kept unexposed to light.

SIGNIFICANCE OF SEWAGE ORGANISMS IN FOOD SUPPLIES.

In the light of our present sanitary knowledge the presence of appre-
ciable numbers of B. coli in any water, food, or drug product is looked
upon as positive evidence of fecal contamination. It is true that
various workers have reported finding this germ from many sources
other than the excrementitious matter of animals. Aside from this
investigation there has been isolated in pure culture the colon
bacillus from the following materials: Sewage, water, ice, milk, cream,
ice cream, butter, buttermilk, sour milk tablets, oysters, clams, flour,
corn meal, wheat, oats, eggs (dried and frozen), wormy peanuts,
and moldy dried fruits. In nearly every instance definite informa-
tion was obtained by inspection showing that the product had been

46 SHELLFISH CONTAMINATION FROM SEWAGE-POLLUTED WATERS.

exposed to conditions favorable to fecal contamination. Occasion-
ally data in regard to the probable sources of pollution of a given
food product can not be obtained, but as the work progresses and
opportunity is afforded to study these problems from various points
of view, it becomes more apparent that the colon test is invaluable as
an index of pollution

Aside from being a mere indication of existing danger from sewage
pollution, the colon bacillus is fast assuming the role of a pathogenic
organism. Various intestinal derangements and other visceral dis-
orders are now ascribed to B. coli infection. In a recent article
Thompson 66 presents evidence substantiating the relationship of
B. coli to certain pathological processes of the abdomen, such as
appendicitis. Under normal conditions the colon bacillus appears
to exist as a harmless organism in the intestinal tract, but in the pres-
ence of irritating substances or under abnormal putrefactive and
fermentative conditions this bacillus seems to become an active factor
in the causation of disease.. The author has recovered a virulent
strain of the colon bacillus and reproduced fatal infections in dogs,
cats, guinea pigs, and pigeons. These results usually resulted from
inoculating the animals with small quantities of a 24-hour bouillon
culture, although in some cases infection was brought about by
feeding material infected with the organism. The colon bacillus
probably plays a further role as a pathogenic organism by producing
toxins in albuminous food materials of a highly perishable nature.
In such a product as shucked oysters, if there is a high bacterial count
with thousands of B. coli present per cubic centimeter of the oyster
liquor, it is highly probable that toxic substances have already been
elaborated. With the consumption of such material gastroenteritis
to some degree must invariably follow. Undoubtedly many obscure
cases of ptomain poisoning and other intestinal disorders of lesser
magnitude could be ascribed to eating tainted food, especially if the
substances are rich in albumin and bacterial activity has appreciably
developed.

In summarizing her work on the chemistry of the colon bacillus,
Leach 40 gives the following analysis, showing the presence of toxins
together with other complex substances in the cell of the colon
bacillus :

Elementary analyses show that age, conditions of growth, and especially the com-
position of the nutrient medium cause bacteria of the same strain to differ widely in
elementary composition. Proteid, nucleo-proteid, nucleic acid, protamin, fat, wax,
lecithin, glycogen, and other carbohydrates have all been reported as obtained from
the bacterial cell in varying degrees of purity. Cellulose seems to be present in cer-
tain species, but by no means in all. Besides the preparations mentioned above,
crystalline compounds have been prepared and purified, proving the presence in the
cell of xanthin bases, pentose, fatty acids, and perhaps thymin and uracil, toxins,
enzyms, and agglutinins have been split off from the cell, but more progress has been
made in determining their physiological action than their chemical nature.

OPINIONS ON SEWAGE CONTAMINATION. 47

In regard to B. coli as evidence of sewage pollution, quotations
from the following authors are cited:

Mason 44 says :

Water which persistently shows B. coli in 1 cc sowings is of very questionable char-
acter, and, should similar results be found when operating with sowings of 0.1 cc, the
water should be condemned.

Regarding the colon bacillus, Dr. Abbott * says:

In the normal intestinal tract of human beings and domestic animals, as well as
associated with the specific disease-producing bacillus in the intestines of typhoid-
fever patients, is an organism that is frequently found in polluted drinking waters,
and whose presence is indicative of pollution by either normal or diseased intestinal
contents; and though efforts may result in failure to detect the specific bacillus of
typhoid fever, the finding of the other organism, Bacillus coli, justifies one in conclud-
ing that the water under consideration has been polluted by intestinal evacuations
from either human beings or animals. Waters so exposed as to be liable to such pol-
lution should never be considered as other than a continuous source of danger to those
using them.

In their work on water analysis, under this subject Prescott and
Winslow 56 conclude as follows:

Although the evidence is quite conclusive that the absence of B. coli demonstrates
the harmlessness of water as far as bacteriology can prove it, that when present its
numbers form a reasonably close index of the amount of pollution the authors above
quoted have proved beyond reasonable cavil. It may safely be said that when the
colon bacillus, as defined by the tests above, is found in such abundance as to be
isolated in a large proportion of cases from 1 cc of water, it is reasonable proof of the
presence of serious pollution.

In speaking of the bacterial content of drinking water, Jordan 3e
says:

The most widely used and, by general consensus, the most valuable of these tests
is the "colon test." This is based upon the circumstances that the colon bacillus,
B. coli, is a common inhabitant of the human intestine, and is found in great abundance
in sewage.

McNaught 42 states that —

The detection of B. coli in a small quantity of a drinking water is a sign of danger
because it indicates excretal contamination, and where excretal contamination occurs
there is a risk that the excreta may contain specific germs of disease.

According to the views of Houston 33 :

The continued persistence of J5. coli in any number in estuarial water may be traced
by continuous excremental pollution and the presence of the unoxidized organic
pabulum in the water.

In his bacteriological report, Connolly 16 says:

Regarding the presence of B. coli in water used for drinking purposes, we have
learned to look with suspicion upon water which contains this bacillus in quantities
of £ of a cubic centimeter, or less, even though the source of the water is apparently
above suspicion. This applies to surface waters, such as are usually collected in
sparsely inhabited watersheds, when there is a greater possibility of colon pollution
from animals than from man. In deep well water the presence of B, coli to any
extent should positively condemn the supply.

48 SHELLFISH CONTAMINATION FROM SEWAGE-POLLUTED WATERS.

The examination made of water and food samples for E. coli has
resulted in diagnosing the presence of this organism only after iso-
lation and making a thorough study of its morphological and bio-
logical characters; even under these conditions many minor differ-
ences are found as to the quantity and character of gas produced,
the time required for coagulating milk, the amount of indol and
nitrites formed, its reaction on various culture media, and other
detailed considerations.

Unless isolated and carefully studied in pure culture, no reliable
means are yet available for distinguishing the true colon bacillus,
by presumptive tests alone, from other gas-forming organisms, such
as B. lactis aerogenes, B. cloacse, etc. However, the presence of any
of these organisms in water is indicative of fecal matter.

There seems to be no question regarding the undesirability of the
presence of the colon bacillus and allied organisms in water used in
any way for food purposes. The relation of this germ to the pollu-
tion or purity of water supplies seems to be now pretty well established
and there can be no doubt that water harboring this germ may be a
constant source of great danger, for where B. coli is found the spe-
cific cause of enteric 'fever, namely, B. typhosus, and also the cholera
spirillum, etc., may be present in sufficient numbers to produce infec-
tion when introduced into susceptible individuals.

SUMMARY.

(1) There is undisputed evidence to show that shellfish become
contaminated when placed in sewage-polluted water, and that B. coli
and B. typhosus will survive for variable lengths of time in the liquor
and the body contents of such shellfish after their removal from
infected water.

(2) The presence of sewage organisms in oysters and other shell-
fish, even in small numbers, may be indicative of great danger; for,
where such organisms exist, the specific cause of enteric fever and
allied disorders may also be found.

(3) The results of many investigators show that sewage-polluted
shellfish have been responsible for the production of typhoid fever
and other intestinal diseases. The most noteworthy cases appear to
have occurred from eating oysters which had been floated in sewage-
polluted water, although instances are cited where shellfish infected
by polluted water, either in their natural or artificial beds, have also
been the vehicle of disease transmission.

(4) The shellfish industries of this country are extensive and
important, comparing favorably with other industries concerned
with the production of food materials. A valuable article of food is
furnished to millions of people by these industries, and thousands of

Sr.M.MAKY. 49

individuals find profitable employment in developing and carrying on
this business in all its phases.

(5) The indiscriminate introduction of sewage into our natural
bodies of water is now the greatest enemy to the shellfish industries.
In order to correct this evil it will be necessary to prevent further
pollution of our waters, or else to remove the shellfish industries
from the grounds subject to pollution.

(6) Oyster beds should be protected from every possible source of
contamination, and they should be located in water proven to be
pure by repeated examinations. These examinations should con-
sist of careful bacteriological and chemical analyses of both the water
and oysters from oyster layings. The laboratory findings should
also be supplemented by systematic inspection of all the territory
which could in any wise affect the condition of the water flowing over
the oyster beds.

(7) The practice of floating oysters in water of questionable purity
should be absolutely prohibited because of the probability of sewage
contamination. When it is desired to remove the gross filth from
the exterior of the shell, oysters may be floated and allowed "to
cleanse themselves" in suitably constructed devices in waters free
from pollution, and containing no less salt than the water in which
they will grow to maturity.

(8) Like other perishable food products, oysters may become unfit
for use if stored or kept under insanitary conditions. This spoilage,
however, may take place wholly from the length of time out of water.

(9) Oysters removed from pure beds may become contaminated
during the process of shucking or preparation for the market in
insanitary shucking establishments. These places should be con-
structed in a sanitary manner and provided with satisfactory appli-
ances for the proper cleansing and sterilization of utensils used for
shipping oysters. Without such devices it is almost impossible to
prepare packages in a sanitary manner. This is particularly true
when cans, barrels, or containers of any kind are used a second time
without proper cleansing and sterilization. When contaminated
these unsterile vessels may become active agents for the dissemina-
tion of disease-producing organisms.

(10) The liquor in the shell surrounding the oysters contains more
bacteria than does an equal volume of meat from the same oyster.
This liquor, together with any sand in the gills of the oyster, can be
removed and the meat chilled at the same time by the use of pure ice
and water. This washing process can be done efficiently within 3 to
10 minutes, depending upon the method employed. Oysters should
not be allowed to soak in fresh water, as they increase in volume,
change in appearance and flavor, and decompose more rapidly than
those not soaked.

50 SHELLFISH CONTAMINATION FROM SEWAGE-POLLUTED WATERS.

(11) Steaming contaminated oysters and clams in the shell, or
cooking them after shucking for 15 minutes at boiling temperature,
practically destroys all organisms -of a questionable character, but
since in practice shellfish are never cooked for this length of time,
cooking can not be depended upon to remove this danger.

(12) Oysters intended to be eaten on the half shell, above all others,
should be produced from beds of unquestionable purity, and they
should be consumed preferably while fresh from the beds; although
if properly kept at cool temperatures under sanitary surroundings
shell oysters may remain wholesome and in good condition for several
weeks after dredging.

(13) The investigations show that vast areas of valuable shellfish
grounds in this country are now \reason ably free from sewage pollu-
tion, but this territory will gradually diminish in size if sewage is not
properly cared for in the future. Comparatively speaking only a
small acreage is now subject to serious pollution. Active steps are
now being taken in some instances 'to overcome this difficulty; how-
ever, it is not the satisfactory conditions which require regulation and
future protection, but those places which are polluted at the present
time, and yet are being used for the cultivation and sale of shellfish.
The presentation of these facts should stimulate every citizen and
health official alike to see that the wastes under their own jurisdiction
are not adding to the difficulty of keeping our natural bodies of water
and the shellfish therein free from contamination.

BIBLIOGRAPHY.

[References consulted in conducting oyster investigations.]

(1) Abbott, A. C. Bacteriological study of water. (In his The principles of bac-

teriology. 1909, p. 589.)

(2) Beale, J. F. An outbreak of typhoid fever due to eating clams from an infected

source. (In The Lancet. 1907, 1 (1): 20-21.)

(3) Bissell, W. G. The bacterial examination of 104 samples of water, together with

a detailed study of the colon bacillus. (In Amer. Public Health Assn.
Papers and Reports. 1904, 29: 360.)

(4) Brewer, W. H., and others. Report of the committee appointed by the State

Board of Health April 15, 1904, "To investigate and report on the possible
danger of typhoid fever resulting from oysters as frequently prepared for
market in sewage-polluted water." (In Connecticut State Board of Health.
28th Annual Report. 1905, pp. 63-69.)

(5) British Medical Journal. Oysters and enteric fever in New Zealand (editorial).

1903, 1 (2199): 451.

(6) Same. Pathogenic oysters in Manila (editorial}. 1903, 1 (2214): 1338.

(7) Same. Remedies for the contamination by sewage of oysters and other mollusks

(editorial). 1903, 1 (2194): 161-162.

(8) Same. Sewage-fed cockles and oysters (editorial). 1903, 1 (2197): 325-329.

(9) Same. To prevent the pollution of shellfish (editorial). 1903, 1 (2197): 334-335.
(10) Buchan, E. F. Mussels and typhoid fever. (In Public Health. London, 1908,

22 (2): 54-56.)

BIBLIOGRAPHY. 51

(11) Bulstrode, H. T. Report upon alleged oyster-borne enteric fever and other

illness following the mayoral banquets at Winchester and Southampton, and
upon enteric fever occurring simultaneously elsewhere, and also ascribed to
oysters. (In Local Government. Board. 32d Annual Report. 1902-1903,
Suppl., App. A, pp. 129-189.)

(12) Chester, F. D. A manual of determinative bacteriology, 1901.

(13) Childs, Christopher. Comparative study of the Lincoln, Maidstone, and Worth-

ing epidemics of typhoid fever. (In Public Health. London; 1905, 18 (3):
121-150.) •

(14) Clark, H. W., and Gage, S. DeM. On the value of tests for bacteria of specific

types as an index of pollution (examination of shellfish). (In Amer. Public
Health Assn. Papers and Report. 1904, 29: 386-397.)

(15) Conn, H. W. The "Oyster Epidemic " of typhoid fever at Wesleyan University.

(In Medical Record. 1894, 46 (24 [Whole No. 1258]): 743-746.)

(16) Connolly, R. N. Bacteriologist's Report. (In State Sewage Commission of New

Jersey. Report. 1907, pp. 47-63.)

(17) Crumbine, S. J. Oysters. (In Kansas State Board o£ Health. Bulletin. 1907r

3 (2): 40-41.)

(18) Doane, R. W. Oysters and shellfish. (In Pacific Fisherman. 1904, g (I):

42-44.)

(19) Ewart, R. J. Some features concerning the sewage pollution of an estuary.

(In Public Health. London, 1909, 23 (2): 51-56.)

(20) Field, C. W. On the occurrence of typhoid bacilli in oysters. (In New York

City Board of Health. Annual Report. 1904, I: 451--i55.)

(21) Same. On the possibility of infecting oysters with typhoid bacilli. (In New

York Zoological Society. 8th Annual Report. 1903, pp. 99-103.)

(22) Fraser, A. Enteric fever and shellfish. (In Public Health. London, 1908, gg

(2): 53-54.)

(23) Fuller, C. A. The distribution of sewage in the waters of Narragansett Bay, with

special reference to the contamination of the oyster beds. (In U. S. Bureau
of Fisheries. Report. 1904, pp. 189-238, Appt)

(24) Fuller, G. W. Recent progress in matters of water supply and sewage disposal.

(In Jour. Amer. Med. Assn. 1905, 45 (15): 1059.)

(25) Same. Shellfish pollution. (In State Sewerage Comjnission of New Jersey.

Report. 1905, pp. 113-144.)

(26) Gage, S. DeM. Methods for testing shellfish for pollution. (Reprinted from

Journal of Infectious Diseases. 1910, 7 (1): 78-86.)

(27) Ham, G. C. Abstract of report of Mr. Ham relative to the floating of oysters in

sewage-polluted waters. (In Connecticut State Board of Health. 28th
Annual Report. 1905, pp. 70-73.)

(28) Herdman, W. A., and Boyce, Rubert. Oysters and disease, an account of certain

observations upon the normal and pathological histology of the oyster and
other shellfish, (In Lancashire Seafisheries Memoir. 1899, No. 1, pp. 1-60.)

(29) Same. Observations on the normal and pathological histology and bacteriology

of the oyster. (In Royal Society of London. Proc. 1899, 64 (407): 237-241.)

(30) Hewlett, R. T. Note on the absence of B. coli, etc., from the normal oyster. (In

Brit. Med. Jour. 1903, 1 (2210): 1082.)

(31) Hill, G. E. The bacterial disposal of sewage. (In Franklin Institute. Jour.

1905, .759 (1): 1.)

(32) Hill, H. W. Report of director of bacteriological laboratory. (In Boston Health

Department. 29th Annual Report. 1900, pp. 63-92.)

(33) Houston, A. C. The bacterial examination of oysters and estuarial waters. (In

Jour. Hygiene. 1904, 4 (2): 173-200.)

52 SHELLFISH CONTAMINATION FROM SEWAGE-POLLUTED WATERS.

(34) Houston, A. C. The vitality of the typhoid bacillus in artificially infected

samples of raw Thames, Lie, and New River water, with special reference to
the question of storage. (In Report to the Metropolitan Water Board. 1908,
pp. 1-32; Review in the Analyst. 1908, 33 (391): 403.)

(35) Johnstone, James. Report on various bacteriological analyses of mussels from

Lancashire and Wales. (In Liverpool Biol. Soc. Proc. and Trans. 1906-

1907, 21: 328-370.)

(36) Jordan, E. O. Bacteriology of water. (In his A text-book of general bacteriology.

1908, p. 516.)

(37) Klein, E. Experiments and observations on the vitality of the bacillus of typhoid

fever and of sewage microbes in oysters and other shellfish. (Review in the
Lancet. 1905, 2 (4285): 1113-1114.)

(38) Same. Preliminary report on cockles as agents of infectious diseases. (In Local

Government Board. 29th Annual Report. 1899-1900, Suppl., App. B, No.
7, pp. 574-576.)

(39) Same. On the behavior of the typhoid bacillus and of Koch's Vibrio in sewage.

(In Local Government Board. 24th Annual Report. 1894-1895, Suppl.,
App. B, No. 2, pp. 407-410.)

(40) Leach, Mary F. On the chemistry of Bacillus coli communis. (In Jour. Biol.

Chem. 1906, 1 (6): 463-502.)

(41) MacConkey, Alfred. Lactose-fermenting bacteria in fseces. (In Jour. Hygiene.

1905,5(3): 333-379.)

(42) McNaught, J. G. The duration of vitality of B. coli communis in various waters

and in sewage. (In Royal Army Medical Corps. Jour. 1905, 5 (1) : 95-105.)

(43) Martin, Sidney. Further report on the growth of the typhoid bacillus in soil.

(In Local Government Board. 29th Annual Report. 1899-1900, Suppl.,
App. B, No. 5, pp. 525-548..)

(44) Mason, W. P. Chapter on the bacteriological examination of water. (In his

Textbook on examination of water. 1910, p. 137.)

(45) Mills, H. F. Typhoid fever in its relation to water supplies. (In Massachusetts

State Board of Health. 22d Annual Report. 1890, pp. 523-543.)

(46) Miquel, P., et Cambier, R. Traite de bacteriologie pure et appliquee a la

me'decine et a 1' hygiene. 1902.

(47) Monsy, M. Des maladies provoquees par 1'ingestion des mollusques. (In Revue

d'hygiene. 1899, pp. 1057-1104.)

(48) Moore, H. F. Oysters and methods of oyster culture, with notes on clam culture.

(Extracted from U. S. Com. of Fish and Fisheries. Report. 1897, pp. 260-
340.)

(49) Nelson, J. Report of the biologist on ostracultural experiments. (In New

Jersey State Agricultural Station. Annual Report. 1890, pp. 249-320.)

(50) Newman, George. Infection of oysters. (In his Textbook on bacteriology and

the public health. 1904, pp. 257-263.)

(51) New York City Department of Health. Typhoid fever. (In its Annual

Report. 1904, 1: 184-188.)

(52). Same. Report on the investigations in regard to the cultivation and sale of
oysters in the city of New York during the year 1904, with particular reference
to typhoid fever. (In its Annual Report. 1904, 1: 313-399.)

(53) Pattin, H. C. The mussel industry at Wells: An interesting story in epidemi-

ology. (In The Lancet. 1908, 175 (4439 [No. 23 of vol. 2, 1908]): 961-962.)

(54) Pease, H. D. A common sense view of the pure-food situation as between the

scientists and oystermen. (Presented at the Norfolk, Va., convention of the
North American Oyster Growers and Dealers Association, May 18, 1910.)

BIBLIOGRAPHY. 53

(55) Prescott, S. (\ Report of the committee on the significance of B. coli in water
supplies. (In Amer. Public Health Assn. Papers and Report. 1903, 29:
356-358.)

.(56) Prescott, S. C., and Winslow, C. E. A. Elements of water bacteriology with
special reference to sanitary water analysis. 1908.

(57) Rhode Island State Commission of Shellfisheries. Annual report. (Made to the

general assembly at its January session, 1910.)

(58) Russell, H. L. The bacterial flora of the Atlantic Ocean in the vicinity of Woods

Hole, Mass. (In Botanical Gazette. 1893, 18: 383-411.)

(59) Savage, W. G. Bacteriological examination of tidal mud as an index of pollu-

tion of the river. (In Jour. Hygiene. 1905, 5 (2): 146-174.)

(60) Sedgwick, W. T. Shall we continue or shall we abate the sewage pollution of

streams? (In New York State Dept. of Health. Monthly Bulletin. 1909, full
ser., 25(10): 263-264.)

(61) Smallman, A. B. Note upon the possible interrelationship between typhoid

and paratyphoid bacilli. (In Jour, of Royal Army Medical Corps. 1905, 5
(1): 137-139.)

(62) Smith, J. L. An investigation into the conditions affecting the occurrence of

typhoid fever in Belfast. (In Jour. Hygiene. 1904, 4 (3): 407-433.)

(63) Soper, G. A. Report of sporadic outbreak of typhoid fever at Lawrence, N. Y.r

due to oysters. (In Med. News. 1905, 86 (6): 241-253.)

(64) Same. The discharge of sewage into tidal waters. (In Jour. Amer. Med. Assn,

1909, 52 (16): 1221-1224.)

(65) Stevenson, C. II. The preservation of fishery products for food. (Extracted from

U. S. Com. of Fish and Fisheries. Bui. for 1898, p. 335^563.)

(66) Thompson, W. H. Acute, subacute, and chronic infection of the kidneys and

other organs by the Bacillus coli. (In Med. Record. 1910, 77 (22 [whole No,
2064]): 907-910.)

(67) Thome, R. T. Introduction to the report and papers on the cultivation and

storage of oysters and certain other mollusks in relation to the occurrence of
disease in man. (In Local Government Board. 24th Annual Report. 1894-
1895, Suppl., App.)

(68) Thresh, J. C., and Wood, F. L. Report on the outbreak of typhoid fever and

other illness due to oysters. (In The Lancet. 1902, 163 (4136): 1567-1569.)

(69) Virginia Health Bulletin. Special report on the sanitary aspects of the Vir-

ginia oyster industry. (1909, 1 (11): 307-328.)

(70) Wood, B. F. Shellfish culture in New York, 1905. (In New York Forest, Fishr

and Game Commission. Bulletin. 1906.)

(71) Wood, G. E. C. Special report to the British Medical Journal on the circum-

stances under which infectious diseases may be conveyed by shellfish, with
special reference to oysters. (In Brit. Med. Jour. 1896, No. 1863, pp. 664-
666; 1896, No. 1864, pp. 759-764; 1896, No. 1865, pp. 852-856.)

Internet Archive Audio

Featured

Top

Images

Featured

Top

Software

Featured

Top

Books

Featured

Top

Video

Featured

Top

Mobile Apps

Browser Extensions

Archive-It Subscription

Save Page Now

Full text of "Shellfish contamination from sewage-polluted waters and from other sources"

See other formats