SPONGE CULTURE. 603 
This is a question of the greatest importance; if we knew that some animal 
species were greedy for sponge larvee the presence of these species at given points 
would be a warning against the choice of such localities for sponge culture. 
Such a series of experiments, easily conducted and absolutely necessary, 
should be made as a preliminary by those who wish to encourage capital to 
take an interest in sponge culture. I intend to publish in the near future 
the results of research of this character. 
We are completely ignorant of the reasons why in nature the number of 
larve that survive transformation is so very greatly limited. It is probable that 
there is a frequent combination of the two reasons on which I have insisted and 
that a certain number of larve after having escaped the attacks of active enemies 
succumb later because they fail to find suitable support at the moment when 
the transformation must occur. 
We are obliged to consider these questions and to revert to them insist- 
ently, for experiments in sponge culture by cuttings the results of which are 
known to us seem to discourage us entirely from attempting sponge culture by 
means of collectors. The authors who made them mention but very superficially 
the attachment of sponges derived from larve on their apparatus. It seems, 
however, that a maximum of favorable conditions was combined there. A 
considerable number of sponges was assembled at a given point constituting a 
kind of parc; the apparatus of sponge culture consisted of collectors, and yet 
these collectors gathered almost nothing. Shall it be assumed that the sponges 
held in the parcs to be divided into sections had scarcely ever any mature larve 
or larve capable of living? This might be possible, although somewhat strange. 
Do cuttings habitually fail to reach sexual maturity under cultivation? Sucha 
conclusion would annihilate certain hopes of sponge culture which shall be 
mentioned later. Shall it be admitted that the larve were emitted and that 
they died in the pares? This would be a very grave deduction for the future of 
sponge culture by means of collectors if we did not observe that sponge cultiva- 
tors have generally made their experiments by immersing the cuttings at a very 
slight depth. 
However this may be, it will be noticed that there remain many obscure 
points by the solution of which alone can we foresee the chances of success of 
sponge culture by means of collectors. We may appraise the amount of capital 
needed for a venture of this kind, but it is absolutely impossible to know how 
many sponges may be garnered and, consequently, to what extent the capital 
engaged might be remunerated. From a purely theoretical point of view, 
sponge culture by means of collectors seems to us the ideal method, as being the 
most rational of all; but, on the other hand, it is the one which possesses the 
least number of scientific data. It would be lack of conscience to advise at pres- 
