[43] THE OYSTER AND OYSTER-CULTURE. (eas 
of food which they get and consume. The peasants of Jutland are 
great breeders of horned cattle, but they have not sufficient food to 
grow and fatten all their calves. Accordingly, many are sold to the 
peasants of the marsh-lands on the west coast of Schleswig-Holstein, 
and upon these extensive pasture-lands great numbers of cattle can be 
raised. Upon the estate of Hagen, near Kiel, there is a carp-pond of 
more than 80 hectares in size which is drawn off every three years, and 
while in this condition sown with oats and clover. It is afterwards 
refilled with water and 30,000 yearling carp placed init. In three years 
from this time, as a rule, the production is 40,000 pounds of food-fish. In 
order to obtain a still greater profit, another lot of young carp was 
once placed in the pond, and this time more than 30,000. In three 
years the produce is indeed a larger number of fish than before, but they 
weigh, taken all together, only 40,000 pounds. The quantity of food 
which the pond supplies in three years is thus sufficient only for the 
growth of 40,000 pounds of carp. 
I do not consider it practicable to fatten oysters by artificial means, 
although in North America and Europe an effort should be made to fat- 
ten planted oysters upon corn-meal. The food of oysters consists of very 
small organic particles which float in the water, ard if one should at- 
tempt artificial feeding by carrying to the oysters of a bed water con- 
taining pulpy pulverized flesh, bone-meal, fish-guano, or corn-meal, it 
would be necessary to prevent the water from flowing off from the bed 
until all the organic matter had been eaten. But by so doing a large 
quantity of foul gas would certainly be generated upon the bed and re- 
main there, so that the oysters, instead of fattening, would become sick 
and die. Among the external life conditions of a biocénose, temperature 
plays an important part. 
In our seas, with their equitable temperature, a mild winter, followed 
by a spring and summer with the temperature much higher than usual 
during spawning time, is especially favorable to the production of a vast 
number of embryos. All living members of a social community hold the 
balance with their organization to the physical conditions of their bioco- 
nose, for they live and propagate notwithstanding the influence of all 
external attractions, and notwithstanding all-assaults upon the continu- 
ance of their individuality. Although every species is differently organ- 
ized, in each the different forces act together for the growth and main- 
tenance of the individual, and although each species has from this fact 
its own organic equivalent, yet they all possess the same (balancing) 
power for the totality of the external conditions of life of their biocdnose. 
Hence all species must respond to a deviation in the conditions of life 
from the ordinary mean by a corresponding action of their forces, so 
that their efficacy may increase or diminish uniformly. If favorable 
temperature makes one species more fruitful, it will, at the same time, 
increase the fertility of all the others. If more young oysters exist 
upon an oyster-bed because the old ones receive more warmth and 
