BACTERIOLOGICAL PROCEDURE. g 
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°—Bull, 136—11 2 
