224 
Part III. — Eighth Annual Report 
methods, new applicances were devised for the collection of the spat. 
Not only must the spat be collected by such appliances, but it must be 
collected in such a way that the removal of the young oysters can be easily 
accomplished without material loss. In the case of twigs, and also in 
the case of stones, which were used as collectors, the injury to and the 
destruction of the young oysters was very great. Tiles — ordinary roofing 
tiles — were employed, and when the young oysters were fit to be removed, 
they were either taken off by the aid of a knife to separate the attached 
valve of the shell from the tile, or the tile was cut into pieces by means 
of a pair of shears or sharp pincers. The better method — breaking the tile 
into pieces, with a young oyster attached to each piece — is continued in 
certain places to this day, the belief being that the piece of attached tile 
is an additional protection to the young and thin-shelled oyster against 
the ravages of the crab and other enemies. There is doubtless a certain 
amount of truth in this, but the protection afforded by the other 
appliances obviates the necessity of the process. The breaking of the 
tile into pieces is still to be seen, especially in the oyster pares of the 
Morbihan. 
The ordinary methods of collecting at present, both in France and 
Holland, is either by specially treated tiles, or by supplying quantities of 
cockle and other shells to the beds. These latter are called natural collectors, 
and are used especially in the district of Arcachon. While on the tile the 
oyster is an appendage, on the shell the oyster which is the appendage 
soon changes places, and the cockle or other shell becomes the appendage 
of the oyster. Empty shells are not always obtainable in sufficient 
quantity, but they are greatly desired in the centres of reproduction, as 
they form not only resting-places for the embryos, but they also supply 
lime to the water for secretion by the growing and shell-forming oysters. 
The tiles, first tried as collectors in the establishment of Madame Felix 
at Regneville, were treated by a process devised by Dr Kemmerer in order 
that the detroquage, or removal of the oyster from the tile, might be facili- 
tated, and the loss by breaking the slender shells of the oyster reduced to a 
minimum. The process is to dip the tiles into a solution of lime and 
water, and allow the tile so coated to dry, then pass the tile through a bath 
of hydraulic lime, mixed with sand, and chalk in some cases. In others 
the tiles are first " white-washed," then dried and coated with a thin 
covering of mortar. The first process permits the young oyster to be 
easily removed ; removal can be performed by the finger-nail, but it is 
generally done by an instrument like a glazier's putty-knife. The coat of 
mortar is for the adherence of the spat. This is the typical method as 
performed at Arcachon. At Wemeldinge in Holland it differs slightly. 
There the mortar used is harder, being chiefly composed of hydraulic lime 
with a little sand and chalk, and so the removal is effected by cutting 
round about the individual young oysters and scraping them off. The 
principle is the same, but the details differ. 
As to the localities suited for the production of spat the pre-requisite 
already mentioned is the presence of a large number of mother-oysters, but 
there are other things which must be taken into account before collectors 
are placed for the reception of spat. While reproduction is attended with 
best results in purely salt water, growth and fattening is greatly promoted 
where there is an addition of fresh water to the salt water of the sea. At 
Arcachon the water of the bay, which is connected with the Atlantic by a 
narrow mouth, and extends at high water to an area of nearly 40/)00 
acres and at low water about 12,000 acres, is Salter than the ocean. It is 
here where the largest operations in artificial cultivation are carried on, 
and where perhaps the most advanced methods are pursued. 
