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Show 41 J ''Can fl:ars-or feas the fails of love retain? " 0 guide my wanderer to my arms again!'' I-Ier buoyant fkiff intrepid U L v A guides, And feeks her Lord amid the tracklefs tides; Ulva. 1. 407. Clandefl:ine marriage. This kind of fea-weed is buoyed up by blacl. ders of air, which are formed in the duplicatures of its leaves, and forms immenfe floating fields of vegetation; the young ones, branching out from the larger ones, and borne on fimilar little air-veffels. It is alfo found in the warm baths of Patavia, where the leaves are formed into curious cells or labyrinths for the purpofc of floating on the water. See ulva labyrinthi-formis Lin. Spec. Plant. The air contained in thefe cells was found by Dr. Prieaiey to be fometimes purer than common air., and fomctimes lefs pure; the air-bladders of fi(h feem to be fimilar organs, and ferve to render them buoyant in the water. In fome of thefe, as in the Cod and Haddock, a red membrane, confi!l:ing of a great number of leaves or duplicatures, is found within the airbag, which probably fecretes this air from the blood of the animal. (Monro. Phyfiol. of Fi!h, p. 28.) To determine whether this air, when fir!l: feparated from the blood of the animal or pl:lnt, be dephlogi!l:icated air, is worthy inquiry. The bladder-fena (Colutea) and bladder-nut (Staphylrea) have their feed-veffels di!l:ended with air; the Ketmia has the upper joint of the fl:em immediately under the receptacle of the flower much difl:ended with air; thele feem to be analogous to the air-veffel at the broad end of the egg, and may probably become lefs pure as the feed ripens; fome, which I tried, had the purity of the furrounding atmofphere. The air at the broad end of the egg is probably an organ ferving the purpofe of refpiration to the young chick, fome of whofe veffels are fpread upon it like a placenta, or permeate it. Many are of opinion that even the placenta of the human fetus, and cotyledons of quadrupeds, are refpiratory organs rather than nutritious ones. The air in the hollow fl:ems of grafles, and of fome unbelliferous plants, bears analogy to the air in the quills, and in fome of the bones of birds; fupplying the place of the pith, which !hrivels up after it has performed its office of protruding the young fl:em or feather. Some of thefe cavities of the bones are faid to communicate with the lungs in birds. Phil. Tranf. The air-bladders of fi!h are nicely adapted to their intended purpofe; for though they render them buoyant near the furface without the labour of ufing their fins, yet, when they refl: at greater deJ?ths, they are no inconvenience, as the increafed preffure of the water condenfes the air which they contain into lefs fpace. Thus, if a cork or bladder G |