A PRACTICAL METHOD OF SPONGE CULTURE, 553 
POSSIBLE LINES OF EXPERIMENT. 
Under instructions from the Commissioner of Fish and Fisheries, experi- 
ments in sponge culture were inaugurated in January, 1901, at Sugar Loaf 
Key and at divers places in Biscayne Bay. From the beginning the aim has 
been not to demonstrate purely scientific possibilities, but to develop, if possible, 
a system of sponge culture having present economic application, the condition 
of the fishery being such that there may arise at any time an exigency demand- 
ing immediate measures of relief to the overtaxed natural beds. 
As has been seen from the preceding historical résumé, a number of theo- 
retical considerations have been offered by various persons and several attempts 
have been made toward a solution of the problem. It has been proposed to 
multiply and improve sponges by growing them from cuttings, from the egg, 
and from the peculiar degenerative masses described by Wilson, and by grafting 
superior varieties upon those less desirable. Each of these, except the third, 
which has been but recently discovered, was considered when the present 
experiments were begun. 
GRAFTING. 
It does not appear that there is much of value in the suggestion as to 
grafting, which is based upon an imperfect analogy between certain aspects of 
the process of growth in sponges and in the higher plants. Cut surfaces of 
related varieties of sponges, as of related varieties of plants, will fuse and heal 
if brought into proper apposition, but there the analogy ends. In grafted 
plants each member of the union (stock and scion) furnishes essential parts of 
the compound, the stock supplying the roots and trunk of a tree, while the 
scion develops the branches, foliage, and fruit. Without foliage the stock 
would die, and without roots the scion would not survive. In plants, too, 
each member of the graft produces a definite influence on the resultant whole, 
making it more or less unlike either of the pure varieties of which it is com- 
pounded. The fruit produced on the scion will differ from that which is 
produced by the ungrafted stock, while the influence of the latter may be seen 
in greater hardiness, a different size and general habit, or in other respects. 
With sponges the case is quite different. The two members of the union will 
have the same organs and be essentially similar even though they may differ 
in quality and texture. One piece may be attached or rooted, but that is 
immaterial and in a measure accidental, for the so-called root is merely a part 
of the surface adherent to some foreign body and performs no particular func- 
tion other than that of anchorage. If the sponge be torn loose, some other 
part of the surface may with equal facility become the root, or more likely the 
sponge will continue to live and grow as an unattached individual or ‘‘roller.”’ 
As has been shown by experiment, if a graft be made, each piece will continue 
to grow independently without influence upon its fellow except in limiting 
