796 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [44] 
conditions and which can be easily detached when the size of the oysters 
is such as to fit them for the parks, or for the bottoms where the mother 
oysters live. 
To Dr. Kemmerer, of the island of Ré,is due the credit of numerous 
ingenious contrivances in the arrangement of tiles as collecting appa- 
ratus. The tile is in fact the fixed collector par excellence, except that, 
like the pavement, it affords too firm and complete an attachment for the 
shell of the oyster, causing the destruction of numerous animals when 
they are detached, and also often giving a defective form to the shell. 
Dr. Kemmerer, in order to remedy these defects, covered the tiles with a 
coating of cement, composed of water-lime, four parts of water and one of 
defibrinated blood. This cement dries rapidly, hardens under water, 
but remains sufficiently brittle to en- 
able the oysters to be detached with- 
outdifficulty. Or, if desired, the entire 
layer of cement can be taken off in a 
single piece, when the young oysters 
are sufficiently grown, and in this man- 
ner transported to a distance to stock 
Go ae ra orer jules: depleted parks or territories, while the 
tile can be recovered with a coating of cement and used a second time. 
The coating mentioned is employed when the labor of preparation can 
be performed at home, but when it is necessary to make repairs, or coat 
the tiles at the parks or preserves, then a coating is used of water-lime 
and Grignon or Vassy cement, very hard plaster, or water-lime and 
pounded brick. The presence of the lime seems, moreover to have, a 
very favorable influence upon the 
deposit of the young. Fig. 16 rep- 
resents the various arrangements 
preferred by Dr. Kemmerer for his 
cement tiles. No. 5 represents the 
tile pierced by a simple hole, 4 the - 
: tile with its coating of cement alone, 
and 1 and 2 the cemented tiles with fragments of grape-vine and shells 
embedded in the cement. Fig. 17 represents the best methods of ar- 
ranging the tiles so as to give a large exposure of surface and sufficient 
solidity to the pile. The various forms of apparatus we have just de- 
scribed are not the only ones in use, nor are they the only ones to be 
recommended. 
The essential condition which should be fulfilled by all collecting 
apparatus, that of offering proper and extended surfaces for the attach- 
ment of the young, is so simple that the mode of constructing apparatus 
can be varied in a thousand ways. The fundamental principle being 
once comprehended, the oyster-culturist, by using the above-described 
collectors as models, can vary the form, the disposition, and the material 
according to his means, the resources of the locality where he labors, 
Fic. 17.—Tile collectors. 
