300 Our Food Mollusks 



perimental beds where differences in soil, time of ex- 

 posure, salinity, and especially variations in the exchange 

 of water over them, should be as great as possible. 

 When the areas chosen had been staked out, the ground 

 was carefully dug over and all clams found were re- 

 moved. Seed clams were gathered sometimes from the 

 same locality, and sometimes at distant points, where the 

 temperature and salinity of the water were very different. 

 Clams to be planted were of different sizes, and some 

 were planted quickly in beds prepared for them, while 

 others were exposed to the air for varying periods be- 

 fore planting. Records of these facts were kept, and 

 results noted when the beds were subsequently dug. In 

 order to determine accurately the amount of growth, the 

 length of each individual clam — and altogether there 

 were many thousands of them — was measured, and those 

 of a size were planted together. Beds were subdivided 

 by measurement, and diagrams in a note-book showed 

 exactly what clams were placed in each square foot, and 

 gave their number. Planting was done during the 

 months of July and August, and the beds were dug a 

 year later. 



Some of the results of these first clam experiments, 

 made on the south side of Cape Cod, may be given 

 briefly. 



The most important fact brought to light was that 

 growth, as compared with that of the oyster, was very 

 rapid. As already stated, the length of each clam was 

 determined just before planting, and again after a year 

 of growth, to determine the amount of increase. But a 

 statement of the increase in length gives no adequate 

 idea of the amount of growth. That is best accom- 

 plished by obtaining the actual increase in volume, and 



