BIOLOGY OF THE OYSTER-GROUNDS OF SOUTH CAROLINA. 
349 
several minutes to settle. The living organisms upon which the oyster might feed do 
not meanwhile descend to form a part of the slight sediment. The volume of water 
necessary for organic analysis may now he carefully drawn up in a pipette thrust well 
into the jar. The specimen represents the average prevalence of oyster food in the 
given locality, and, if properly collected, it may be proven by the microscope to be 
free practically from the organic matters which should not be included in the food of 
the oyster. 
The Wancklin method of determining the albuminoid ammonia is then followed. 
With skillful handling this method is certainly an accurate one, the Nessler color test, 
readily determining the presence of —<too °f a part of ammonia in 1,000,000 parts of 
water. The free ammonia given off when the water is merely boiled, must be consid- 
ered as representing ammoniacal salts, derived in great part from disintegrated tissue, 
and marks the impurity of the water. The solid organic matter in the water, which 
we will have to allow is mainly oyster food, is thus left coagulated. A strong caustic 
now introduced destroys this organic residue, and the product of combustion is quan- 
titatively determined as albuminoid ammonia. That the amount of albuminoid 
ammonia in uncontaminated salt water will (with due biological precautions) repre- 
sent the quantity of organisms present must be conceded. In the present work this 
method was followed for lack of a better one. 
Referring to the albuminoid ammonia results in the table of analyses, we may get 
some general idea of the food character of the water, as well as of local differences. 
We may see, for example, the general uniformity in the albuminoid constituents, 
averaging perhaps about parts per 1,000,000 in almost every locality in the State. 
This amount is certainly not as great as that shown in the oyster-grounds of the north 
side of Long Island; but, on the other hand, its uniformity in food constituents must 
make it at least a more than fair feeding- ground. In a general way the waters of the 
north side of Long Island are a third richer in them feeding constituents than those 
of South Carolina, while Great South Bay* (Blue Point), which is practically a huge 
u claire” built by nature on French principles of oyster-culture, is thrice richer. 
The effect of tide and depth of water upon the total amount of oyster food in a 
given locality has already been described. 
The general appearance of some of the typical organisms from the stomach contents 
of the South Carolina oyster has been outlined in Plate lxvii, Fig. 2, which represents 
the objects as magnified about 225 diameters. Nos. 1 to 20 are common forms of 
diatoms. 
In this connection it is to he noted that hrackish waters (sp. gr. 1.010 to 1.012) are apparently 
richest in oyster food; The studies of the Great South Bay, for example, whose density is kept uni- 
formly low (1.010 to 1.013) hy the entrance of a number of small, fresh, sluggish streams, show the pres- 
ence of the greatest profusion of diatoms, hoth in number and species. In American oyster-culture tho 
time is not far distant when oyster ponds of this favorable character will be employed for preparing 
oysters for market. In introducing the French systems, however, careful studies are yet to be given 
the questions of compensation of labor and of altered conditions of locality. 
