OYSTER-CULTURE IN FRANCE. 
373 
allowing the basin to thoroughly purify, and during this time the muddy tracts had 
been roughly macadamized with clay and gravel. About the middle of April the 
water was gradually admitted. A week later oysters were introduced to furnish the 
spawn. These were scattered in the deeper parts of the lake at about forty to a square 
yard. The water was now daily changed at the flood-gates till the first appearance 
of spawn (May 15). This was the sign that the collectors should be put in place and 
that the flood-gates should be closed. Since that time, up to September 1, no water 
and consequently no oyster fry had been allowed to escape. Loss from evaporation 
was several times made good by allowing the entrance of tide water, a precaution 
hardly necessary because evaporation had in a measure been counterbalanced by sev- 
eral small springs occurring in the bottom of the lake. These, moreover, exercised a 
very salutary effect in keeping the gravity of the water slightly lower (1.021 to 1.023) 
than in the open harbor. The temperature of the confined water became gradually 
higher (5° to 8° F.) than that without, while the water volume was yet sufficient to 
guard against sudden changes of air or weather. Obviously, absence of strong cur- 
rents tended to a minimum of sediment accumulation. It was soon evident that the 
success of the experiment was a pronounced one. A dense set was apparent through- 
out the entire bottom. The spat had even attached to the stouter sea- weeds. Owing 
to a minimum of sediment both sides of the tiles in the collectors were usually well 
covered, each tile showing on an average 400 spat. The set was sometimes as dense 
as 3,000 per tile. 
The principles to which Mme. de Saint-Sauveur has attributed her success are as 
follows : 
(1) The necessity of inclosing a large area in order to present a great water surface for the 
absorption of air. 
(2) The necessity of thoroughly drying out the hasin for at least two months, doing away 
entirely with animal and plant life and allowing the clayey bottom to become purified for the 
following season. 
(3) In the management of the pond the necessity (1) of introducing a small hut continued supply 
of fresh water to compensate for evaporation ; (2) of a uniform and low density (1.022) ; (3) of a depth 
of water sufficient to guard against sudden changes in temperature or density. 
The success in the management of this closed pond has been so remarkable that 
if continued during following seasons it will insure the establishment of permanent 
stations of this character. It is noteworthy that from the time that water was allowed 
to fill the dried basin a healthful condition prevailed and was apparent throughout. 
Sea-weeds became sufficiently abundant to aid materially in oxygenating the waters, 
and to provide the richest of feeding for the contai oysters. In former experiments 
the difficulty has been malaeration, causing the death of animal life and the subsequent 
empoisoning of the water. Breneguy has refuted most clearly the doctrine of Chaumel, 
dressy, and de Wolbock, that “current is indispensable to the life and transport of 
oyster fry.” * The question seems rather one of perfect aeration and of lack of 
sediment. 
In relation to our present need of seed-culture the success at Breneguy should be 
seriously considered. The ease with which our species of oyster may be artificially 
fertilized would allow us to introduce in a pond of this kind myriads of active fry, 
could we be but sure that natural conditions would be favorable for their set. We 
Vide Hausser, ref. 47, 22. 
