[7] OYSTER CULTURE IN MORBIHAN. 949 
“The conclusion was easily deduced; the blue tint announced that 
the spawning time was at hand, and that we should hasten to arrange 
the apparatus. I announced to M. Coste the happy result I had obtained, 
and predicted a complete triumph.” 
This result, which to-day may seem of slight importance, had consid- 
erable weight at the time of its publication, ten years ago, When it 
became known that about the 1st of July, the time when the milky hue 
changes to the bluish color, was the commencement of the spawning 
season, then it was evident that one might with certainty, and without 
danger of interference from sediment, make ready the collectors to re- 
ceive the young oysters. 
From the time when this matter was determined, the problem of the 
arrangement of the collectors was solved. 
In this way, moreover, judicious observations conduced to progress, 
and divers experiments were made. Attempts were made to collect the 
young oysters by keeping the spawning oysters shut up in basins fur- 
nished with sluices, and also by simply placing the collectors in the water. 
This last method produced magnificent results. 
It was now well understood that the spawning season dated from 
about the 1st of July, and it was also known that the best results had 
been obtained in the deeper water; but it had not yet been ascertained 
that there was a classification to be made, and a judicious method to be 
followed. 
To Dr. Gressy, of Carnac, is due the following observations: “The | 
collectors should be placed in the shallower areas from June 15 to July 
10, and in the deeper areas from July 10 to August 1. 
“Tf, during the first-named period, the collectors are set in the deeper 
areas, polyps will grow over them, and they will receive only an insuffi- 
cient number of embryo oysters. Polyps are never observed on the 
collectors in the shallow areas, because the young are unable to resist 
the heat, when exposed at low tide, but they are most abundant upon 
those which are seldom uncovered, or only at the spring-tides. Nothing 
can be more easily proved in the breeding parks. The deeper down we 
go, the more numerous and more luxuriant will we find the polyp growths, 
suspended over the collectors. 
‘‘By the 10th of July, the polyps have about finished spawning, while 
the oyster spawn is still very abundant; hence, after this time, the young 
oysters may attach themselves to the collectors, without fear of being 
smothered by the growing polyps. This physiological law, which I have 
observed in my parks, has not hitherto been made known.” 
It will, therefore, be seen that, before placing the apparatus intenced 
for the attachment of the embryo oyster, it is necessary, not only to 
await the month of July, so as to escape the deposit of sediment, but 
also to follow a methodical order, and work in the shallower areas from 
the middle of June to the middle of July, and in the deeper ones from the 
middle of July to the first part of August. 
