( 380 j 
arisen by accumulation of sand. If it must therefore be considered 
as proved, that places which had formerly value for the oyster- 
culture, have lost in quality, the evidence has however not been 
given that by such influence the good qualities of the oysterbeds in 
general should have been lost. 
The assertion, as if a change, a degeneration of the oyster itself, 
were the ground of the less favourable results of the culture in the 
later years, is founded on the supposition that an injurious influence 
is still exercised by the French oysters which were many years ago 
imported in the Eastern-Schelde, and that therefore the Zeeland- 
oysters should have lost of their good qualities by interbreeding. 
This idea finds a slight affirmation in the extraordinary rich brood- 
production of these later years. But really not more than the 
slightest; for in the first place it is not at all sure that the French 
oysters produce a more numerous posterity than the original 
Zeeland oysters. And in the second place the abundance of births 
can very well be explained by the great mortality and the unusual 
numerous population of oysters, which for many years have been 
found in the Zeeland-oyster-beds; abundance of births, bad growth 
and great mortality are symptons connected with one another; which 
combined, give proofs of overproduction and of insufficient nourish- 
ment of the separate individuals caused thereby. 
Proofs can easily be furnished, that the very first young Zeeland 
oyster taken, still exhibits the same excellent disposition to grow 
to be an extremely suitable shell-fish fit for human food. This 
proof is given by the excellent results, which again for instance in 
this year, have been obtained with young Zeeland oysters transported 
to other waters; to de Grevelingen, near Bruinisse ; to some places 
on the Western-Schelde; to places in the Zuiderzee, near the coast 
of ezel, 
Not the oyster itself is therefore to be blamed for the decline 
of which the cultivators complain, but the oyster-culture as such. 
The circumstances, the favourable results in the first years, competi- 
tion, which raised the leases tremendously, have occasioned heavier 
claims to have been put to the oyster-producing territory. Conside- 
ring the thorough renewal of water of some hundred millions cubic 
Meters of water with every tide, and taking for granted that the 
oyster feeds itself with the small organisms, which are carried 
along with the tide and form the so-called plankton, the quantity of 
oysters to be obtained seemed indeed unlimited. From investigations 
made in Zeeland for some years, it has however become evident 
that the oysters do not chiefly feed on plankton but on small vegetable 
