156 



EECEEATIYE SCIENCE. 



ing of the water was produced by the ac- 

 tive movements of cilia, and not merely by 

 the passage through it of motionless pro- 

 cesses. Such cilia, if indeed they be so, may 

 occasionally be seen on other parts of a 

 filament, and the most rapidly moving speci- 

 men we ever met with was furnished with 

 them in unusual profusion. Before finally 

 putting this down, let us add a drop of chlo- 

 roform ; the motion is instantly stopped, and 

 laudanum produces a similar effect. 



"What relation is borne by Oscillatoria to 

 other plants is yet a mystery. If we look at 

 the dried-up material taken from the gravel 

 path, it wiU be found to be motionless, in 

 much shorter pieces, and those contained in 

 gelatinous tubes ; the same thing evidently, 

 but in a different state. As it would have 

 been impossible, before the changes had been 

 observed, to predicate that from an egg, a 

 motionless speck, should come an active, vo- 

 racious caterpUlar, which should turn again 

 to a quiescent chrysalis, and whence should 

 emerge at last a graceful volant denizen of 

 air ; so, till all the changes involved in the 

 life-history of this simple vegetable are 

 known, we are unable to say what phase the 

 motUe stage we have been examining may 

 represent. Probably, when the pools or 

 damp places it inhabits are slowly dried, it 

 assumes the altered form with investing 

 hyaline tubes ; when quickly dried, each fila- 

 ment breaks up into its component joints (c), 

 which are probably analogous to the buds of 

 higher plants. Sometimes we find a portion 

 assuming a different appearance, enlarged 

 and thickened (d), with spaces on each side 

 of it bare of colouring matter — such may be 

 a sporange, or reproductive body ; and there 

 are good grounds for thinking we know but 

 the caterpillar state, the connection of which 

 with its perfect condition remains yet to be 

 traced. To any who have taste for such an 

 investigation, a rich reward in continually 

 renewed interest may safely be promised, and 

 it may be their good fortune to add another 



leaf to our yet most scanty knowledge of 

 the " Book of Nature." 



The "greenstuff" from thepaling is a plant 

 of another kind ; like little beads of a rounded 

 or oval form, and delicate grassy green colour 

 (Fig. 2). Generally each little "bead" is 



•^ . 

 c, 



^ o 







Fig. 2. 

 free, sometimes two may be seen united, and 

 occasionally four or six in short strings. If 

 this be really a unicellular plant ; if each of 

 these little "beads," or "cells," as they are 

 termed in scientific language, be really a 

 plant in itself, 



" Totus, teres, atque rotundus," 



(which may be freely translated for the occa- 

 sion, "perfect, round, complete in all its 

 parts"), it surely must, as the late lamented 

 Professor Henfrey said, be the most numerous 

 in individuals on the face of our globe. But 

 it requires to be grown and watched, varying 



loOO 



^Sbo SSSSSBdo 

 SS09 00 pQ oa no 



QQQO oqOq OQgg 



nr»nc\ .,N»~ ^"u ""' 



CO 00 



Fig. 3. — Ulva crispa. a, portion of frond in its ma- 

 ture state ; b, e, c, early stages ; d, zoo-spores (?). 



external circumstances of temperature, amount 

 of moisture, exposure, and so on, with a good 

 deal of ingenuity, before this can be safely 

 affirmed. 



