1268 BULLETIN OF THE BUREAU OF FISHERIES. 



The results, at this time, of the investigation that I have been conducting 

 for the Bureau dviring the past five summers at the Beaufort laboratory justify, 

 it seems to me, the point of view above outlined. Two new methods by which 

 sponges may be grown have been discovered, and both of these methods attest 

 the remarkable regenerative power of the body cells of sponges. That both 

 methods are applicable to the commercial sponge there can hardly be a doubt. 

 Whether at the present time any economic advantage would accrue from the 

 practice of either is perhaps doubtful, in view of the fact that sponges may so 

 successfully be grown from cuttings — a method first practiced by Oscar Schmidt, 

 and further developed in this country by Richard Rathbun, while in recent 

 years H. F. Moore has brought it through a long series of admirable experiments 

 to a high degree of efficiency . 



But while the methods which I shall presently describe may not now be of 

 practical utility, they add something to our knowledge of the underlying scien- 

 tific principles of sponge culture. And it is a truism that such principles are 

 the funds, so to speak, on which the practice of succeeding generations draws in 

 the conduct of economic enterprises. I am convinced that our knowledge of 

 these scientific principles of sponge culture may be vastly increased. Future 

 researches will surely clear up, among other points, the relation between the 

 formation of sexual products (ova and sperms) , of asexual masses which trans- 

 form directly without passing through the swimming stage (ciliated larva) , and 

 of asexual masses which imitate the egg development in passing through the 

 stage of the ciliated larva. I may add that such a relation is "cleared up" to 

 the eye of science (in contradistinction to metaphysics) only after the discovery 

 of the actual treatment to which, when the sponge tissue is subjected, it responds 

 by the development of this or that reproductive body. In this instance, as in 

 many such biological problems, the most intimate knowledge of the structure 

 and movements of the cells concerned in the production of each kind of body is 

 necessary. But such knowledge of itself falls short, and remains unsatisfactory 

 until it leads up through experiment to an actual control of the phenomena — 

 to the power which can at will compel the sponge to produce the one or the other 

 kind of reproductive body. 



The first of the two new methods to which I have alluded has been described 

 in Science. ° It is briefly as follows: 



If sponges are kept under appropriate conditions in aquaria, the body dies 

 in some regions, but in localities the cells remain alive and congregate to form 

 masses. In the production of such masses the component cells lose their indi- 

 viduality, fusing with one another to form a continuous mass of protoplasm 

 studded with nuclei (a syncytium). Such masses of syncytial protoplasm are 



o Wilson, H. V. : A new method by which sponges may be artificially reared. Science, June 7, 1907. 



