Wilson — A New Method 
95 
* 9 ° 7 \ 
of the vessel, but so feebly as to be easily shaken loose. In 
order to see if they would transform when returned to natur- 
al conditions, I devised the simple plan of enclosing- them in 
fine bolting-cloth bags which were hung in a live-box float- 
ing in the harbor. The bags, rectangular, were divided into 
compartments about an inch square with the two flat sides 
nearly touching. In each space an isolated plasmodial mass 
was inserted, and the bag sewed up. It was found that in 
such bags the masses were held in place long enough for 
them firmly to attach to the bolting cloth. Once attached to 
the cloth they grow, sometimes quite through the wall of the 
bag to the outer water, and transform into perfect sponges 
with osculum, canals, pores and flagellated chambers in such 
abundance as to be crowded. 
This ability to undergo — when the environment is unfavor- 
able but not excessively so, regressive changes of differentia- 
tion resulting in the production of a simpler, more uniform 
tissue, is something that is plainly useful, i. e., adaptive. In 
the simplified state the sponge protoplasm withstands condi- 
tions fatal to such parts of the body as do not succeed in 
passing into this state, and on the return of normal condi- 
tions again develops the characteristic structure and habits of 
the species. That this power is exercised in nature there can 
scarcely be a doubt, since the conditions that are present in 
an aquarium must now and then occur in tidepools. 
It is probable that the power thus to degenerate with the 
production of masses of regenerative tissue is general among 
sponges. I first discovered the phenomenon in Microciona , a 
very different form from Stylotella and one in which the skel- 
eton includes much horny matter. And in two other Beau- 
fort species I have succeeded in producing the plasmodial 
masses. There is every reason for believing that the com- 
mercial sponge shares in this ability. If this is so, we have 
here a means of propagation which with a further develop- 
ment of methods may at some time become economically 
practicable. In any case it is now possible to study the dif- 
ferentiation of a quite unspecialized tissue, one that is physi- 
