654 JULIAN 8. HUXLEY 
there was no growth of the stolons (except a very slight growth 
in one case). In n/8,000 the appearance of the stolons was 
nearly normal, but in the two higher concentrations they were 
adversely affected and showed contraction. As regards the 
zooids, the circulation was in all subnormal. A considerable 
degree of draining (resorption) tock place, but was never 
complete. Several became opaque and spheroidal without 
appreciable draining (Clavellina type of dedifferentiation). 
The zooids mostly still showed normal tone after twenty-four 
hours, while in higher concentrations all had begun to shrink 
by this time. A slight effect on the stolon was indicated by 
opacity and clubbing of the ends. 
Tn solutions from n/16,000 to n/64,000 inclusive, a consider- 
able proportion of the stolons showed new growth. In no case 
was the stolon adversely affected, but it always remained of 
normal appearance with flat cells. Of those zooids which did 
not die the large majority had begun to be resorbed in the 
typical way before forty-eight hours, and some of them became 
completely drained. ‘The n/32,000 solution seemed to be the 
most effective in causing this draining, but this may have 
been an accident, although it is perfectly possible that the 
n/64,000 solution is less effective because too weak. 
The controls, apart from a small proportion which started to 
drain early (an occurrence which takes place in all collections 
of stolon-zooid systems chosen at random, and presumably 
depends on the internal condition of particular zooids), 
remained normal, the zooids completely expanded, for forty- 
eight hours and most of them for seventy-two hours. Most of 
them showed slight new growth of the stolons, as is customary 
in the early stages of stolon-zooid systems, but they were not 
kept long enough to see whether stolon-resorption, which only 
occurs after several days, would supervene. 
We can classify the effects broadly as follows. High con- 
centrations kill the whole organism speedily. The next 
lower degree of concentration causes contraction (dedifferen- 
tiation) of both stolon and zooid. No resorption is possible 
in this case, whether of the zooid or of the stolon. The next 
