SEWAGE CONTAMINATION OF OYSTER BEDS. 219 



beaclies near the Fields Point sewer oiitlet and later at various other 

 localities in the river and bay. In the examination, inoculations were 

 made from the liquor contained between the shells, from the contents 

 of the intestines, stomach, and rectum, and in some cases from por- 

 tions of the visceral mass. In order to obtain samples of the juice from 

 an oyster under aseptic conditions, the specimens to be examined were 

 scrubbed thoroughly in tap water with a stiff brush, washed off in 

 running sterile water, and dried .on a sterile towel, after which ihe.j 

 were opened with a sterile knife. To obtain cultures from the stomach, 

 the top of the mantle covering the anterior end of the oyster was slit 

 open and the large palps on either side of the mouth pushed aside; 

 the mouth region was sterilized by passing a hot scalpel over these 

 parts and a portion of the stomach contents was drawn out by means 

 of a fine pipette or platinum loop introduced through the mouth open- 

 ing. Cultures from the intestines were made in the following manner: 

 After opening the shell, the oyster was removed from the shell and 

 dried between filter papers. A hot spatula was then passed upon the 

 surface of the mollusk directl}" over that poilion of the intestine which 

 it was desired to reach, and the tube was then opened with a sterile 

 scalpel. Through this opening a portion of the contents was drawn 

 out hj means of a pipette or platinum loop. Portions of the visceral 

 mass were obtained by cutting out cubes of flesh from that portion of 

 the body after sterilizing the surface with a hot scalpel. 



The samples thus obtained were subjected to the same tests that 

 were used in the water anal^'sis — the dextrose fermentation, litmus 

 lactose agar, and carbol broth. In these tests a nutrient gelatin 

 medium containing 0.05 per cent carbolic acid was also employed. 



Resxilts. — The first specimens examined were oysters from Fields 

 Point. They were collected at low tide in about 2 feet of water on 

 the long flats that make out from the southern shore of the point. 

 Though live material was scarce near shore, large numbers of dead 

 shells were everj^where scattered over the flats at a little distance from 

 land, and when the oysters obtained from this locality were opened 

 they were found to be lean and unhealth3\ The bodies were dark brown, 

 almost black in color, while the mantle folds vv-ere, in 8 of the 10 

 examined, a bright green color. 



There are also some clam flats and thatch grass, in which mussels 

 were found, on the south shore of the point, within half a mile of the 

 sewer outlet. A good set of clams was found in this beach in 1900, 

 and at the time these specimens were secured several diggers were 

 rapidly filling baskets for the market. These clams WTre large and fat, 

 though the shells were black, and the "rims" and "snouts"' were dark 

 5'ellow in color. There were, however, large numbers of dead clams 

 strewn everywhere over the beach, and a drift of v/hite shells marked 

 the high-tide limit. When these clams were dug samples of the sand 



