608 BULLETIN OF THE BUREAU OF FISHERIES. 
water; the cuttings should be immersed at a moderate depth in order that it 
may be easy to manipulate and observe them. ‘The growth is more rapid when 
the current is strong, but the shape is then more frequently bad and the 
skeleton hard. This point, however, is not quite elucidated by the author. 
Under favorable conditions the cuttings double their size in six months, conse- 
quently eighteen months to two years would suffice to produce a sponge of com- 
mercial size. ‘‘It is quite possible that with state protection to the planters and 
better methods to be determined upon by further experiment, sponge culture 
might be profitable.’’ Nevertheless, the author comes finally to the conclusion, 
mentioned above, that the most rational method in his opinion is the one closest 
to oyster culture. Let us observe that the estimates of Monroe as to the time 
necessary for a sponge to attain a commercial size are based on the results of one 
single experiment which was especially lucky and extended over only six months. 
At the request of sponge merchants of Sfax, the Direction Générale des 
Travaux Publics (of Tunis) undertook researches on the biology of commercial 
sponges, and erected for this purpose a laboratory on piles in the open in the 
harbor of Sfax. This laboratory was intrusted to the supervision of Raphael 
Dubois. Allemand was appointed assistant director and made a series of experi- 
ments in sponge culture by cuttings, which he continued for two years and the 
results of which he published in 1906. He tells us that the sponges to be divided 
should be gathered with great care and utilized as quickly as possible after being 
taken, or they should be allowed to heal entirely in running water before cutting 
them up. He divided them with a very sharp blade previously immersed in 
boiling water for each cutting. The operation is successful when it takes place 
at a temperature of about 15°. If made at this temperature the healing of the 
cuttings rarely took more than three months, while in winter it is very slow, as 
is also the growth of the cuttings in this season.” “ On the other hand, the vivid 
light was, as in the experiments of Schmidt, detrimental to the healing as well 
as to the development of the cuttings. It is, consequently, of great advantage 
to shelter them. 
In some ten months the cuttings grow to three times their original size. ‘‘In 
proportion to the growth observed, a fragment can form a sponge of commercial 
size (0.30 meter in circumference) only in four or five years.’”’ In short, the 
Hippospongia equina elastica developed somewhat more rapidly than the Eu- 
spongia officinalis adriatica of Schmidt. The author remarks that the apparatus 
of sponge culture must be very resistant and especially well sheltered. It is 
necessary to discontinue wooden materials, which suffered from the boring in- 
a This concurs entirely with the results obtained by Schmidt and Buccich. The healing and growth 
of the cuttings is more rapid when they are not kept at the bottom of the water. Bidder, as we have 
seen, called attention to this fact. 
