The 'muslin' in the hypothetical plexus seems to be very coarse in some specimens and finer in others--the young and active individuals enduring severer forms of section than the old. And in exploring by graduated stimuli, areas of different degrees of excitability may be mapped out, and these areas are pretty large, averaging about the size of one's finger-nails. I am rather inclined to think that these areas are determined by the course of well-differentiated nerve-tracts, while the less-differentiated ones are probably more like muslin in their mesh. But the only reason why I resort to the supposition of nerve-tracts at all is because of the sudden blocking of contractile waves by section, and the fact that stimulus (tentacular) waves very often continue to pass after the contractile ones have been thus blocked. I am sorry I made the ungallant mistake about Miss Lawless, but I had no means of knowing. If I had known I should not have written the letter, because I am almost sure the movements of the Medusa were accidental, and my pointing out this source of error may be discouraging to a lady observer. I remember thinking you were too diffident about the bloom, but I suppose that is the advantage of experience; it keeps one from forming too high hopes at the first. The rest of your letter contains glorious news. Cohn, I suppose, is about the best man in Europe to take up the subject, and although I cannot conceive what else he can do than Frank has done already, it is no doubt most desirable that his opinion should be formed by working at the problems himself. The other item about the effects of feeding Drosera is really most important, and in particular about the starch. I have heard the doubts you allude to expressed in several quarters, but this will set them all at rest. It was just the one thing required to cap the work on insectivorous plants. What capital work Frank is doing! I have nothing in the way of boasting to set off against it. The year has been a very bad one for jelly-fish, so that sometimes I have not been able to work at them for several days at a time. The most important new observation is perhaps the following. [Illustration: FIG. 3.]