PROGRESS IN BIOLOGICAL INQUIRIES, 1926 657 
owned this particular bed said they got a splendid set, but we are not 
claiming that we produced it. 
Another question that is always interesting and important is the value of 
the scientific work to the industry. From my observations made in the vicinity 
of Milford Harbor over a period of years we accumulated some knowledge as 
to the condition of the oysters each year and the hydrographic conditions on 
the beds in Long Island Sound. I found favorable conditions for a set in some 
of the inshore regions in 1925 and advised the oystermen to plant their shells 
as early as possible. The oystermen plant from July 15 to August 15 usually. 
This year they got their shells out as rapidly as possible, with the result that 
they were able to secure the early set on July 27 out in the deep-water regions 
which ordinarily would not appear until the middle of August. The best crop 
of seed oysters since 1914 was obtained that year. 
Mr. Pryruercu. I have here a few exhibits to be passed around. 
Here is some brush with oysters attached, which was planted in 
1925 in Milford Harbor. The brush disintegrates or is destroyed 
by shipworms, with the result that the oysters attached to it break 
apart or can be separated as single specimens, whereas when they 
are collected on shells the oysters continually crowd each other as 
they increase in size. 
Doctor Fisu. I would lke to ask Doctor Galtsoff a question re- 
garding the feod of the oyster. You stated that 99 per cent of the 
forms contained in the water are taken in by the oyster. Does this 
mean 99 per cent of the larger forms, or of the total ? 
Doctor Gaursorr. That really means of the the microplankton. The 
water used was taken out of the tank where the oysters are kept. Dino- 
flagellates and diatoms were the principal organisms present. I col- 
lected one liter of water after it had passed through the gills, and 
after examination it was found to contain nothing but mucus. All 
these small forms constitute the food of the oyster. There is some 
question as to how all these things are taken into the stomach and 
consumed. I am going to study more carefully next year what kind 
of food the oyster takes in. We know at the present time that the 
oyster has the ability to select its food according to its size. It may 
be that it can select its food according to the kind of food desired. It 
may be that some of the diatoms are rejected. An important con- 
sideration is, what propels the food particles to the mouth cavity 
and then separates them—rejecting some and accepting others. We 
have found a method by which we can measure the amount of food 
passing into the mouth cavity. We must find out if everything is 
consumed or if something is rejected, and what part of the food is 
desirable. I know of one large oyster bed—15 by 6 miles—in which 
none of the oysters are of value. They are very dark and can not be 
marketed, probably due to lack of food. When we know exactly 
what the oyster needs for its food, we can avoid this. We may 
supply some artificial food, as is done in France; but first it 1s 
necessary that we know the type of food as well as the quantity 
required by the oyster. 
Doctor Fisu. I was wondering if possibly out of the total amount 
of food there was a minimum below which no use was made by the 
oyster. 
Doctor Gautsorr. Possibly that is the case. We have no positive 
evidence; in our experiments we found nothing to confirm this fact. 
It seems to me that every organism about 2 microns in diameter can 
pass through the gills easily. 
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