PEOGRESS IN BIOLOGICAL INQUIRIES 21 



By analyzing the water that had passed through the oysters' gills, 

 Doctor Galtsoff discovered that over 99 per cent of the diatoms and 

 dinoflagellates consumed by them are caught by gill the epithelium. 

 The discharged water contains almost nothing but mucus. However, 

 the experiments made by him in October in Doctor Pease's New York 

 laboratory show that only a very few bacteria are retained by the gills, 

 most of them passing through the gill cavity. Bacillum coli alone 

 were used in the experiments. It is believed that these laboratory 

 e periments will be effective in solving the various practical problems 

 of oyster culture and sanitary control of the oyster industry. 



In order to determine which are the best methods for maintaining 

 and increasing the natural supply of oysters, additional experiments 

 were conducted at the shellfish laboratory at Milford, Conn., relative 

 to the life history, habits, environment, culture, and artificial propa- 

 gation of the 03 r ster. Milford Harbor is typical of the numerous 

 coves, bays, and estuaries that are the natural habitat of the oyster, 

 and in former times shellfish were very prolific there, so that scientific 

 data derived from detailed stud}' of the oysters present in this small 

 body of water can be used as the basis for developing oyster culture 

 in other localities. 



To rehabilitate this small harbor, the Connecticut Oyster farms Co. 

 supplied oysters enough to establish two fair-sized spawning beds, 

 one of which was located on the tidal flats and the other in the chan- 

 nel. As these waters are at present unpolluted to any serious 

 degree it is possible to study the oyster under conditions similar to 

 those under which it thrived in years past. 



A brief resume of the various studies and experiments made and 

 the results obtained follows. 



Spat collection. — The tidal flats in the harbor were planted with 

 brush, shells, and tile collectors, each of which successfully demon- 

 strated the value of such flats for producing annual harvests of seed 

 oysters. The birch brush, which was planted in rows and stacks 

 over an area of about 6 acres, was covered with a good set of oysters 

 for a distance of 2 feet above the bottom, and after the oysters had 

 attained a good size, the brush was transplanted to the deep-water 

 beds in the sound. 



At the suggestion of Capt. Charles E. Wheeler, manager of the 

 Connecticut Oyster Farms Co., a dozen wire baskets were filled with 

 oyster, clam, and mussel shells and placed on the flats. These proved 

 to be the cheapest and most practical type of collector used in the 

 experiments. Each of the shells on the top, bottom, and sides 

 of the baskets was covered with from 100 to 200 spat, those in the 

 layer just inside were covered with from 12 to 50 each, and those in 

 the very center caught from 2 to 10 spat each. Each bushel of 

 oyster shells caught about 15,000 spat, while the baskets of clam 

 and mussel shells caught a few thousand less than this. This method 

 can be made even more efficient by using the large, brittle oyster shells 

 from the Housatonic River, which make it possible for more spat to 

 attach in the center of the baskets and which, after being trans- 

 planted to off-shore grounds, easily break up, allowing the young 

 oyster ample room for growth. 



Another type of collector used in the experiments was half-round, 

 glazed tile, having a surface of about 1 ,000 square inches. The aver- 

 age number of spat collected by each tile from the first set of oysters 



