HARDWICKE'S SCIENCE-GOSSIP. 



103 



and its reappearance its diastole. The contraction 

 and expansion are rhythmical, occurring at regular 

 intervals, like the systole and diastole of the heart. I 

 have noted the phenomenon, and seen that, when 

 the space disappears, two small triangular canals are 

 seen (Fig. 55), then gradually the vesicle reappears, 

 growing larger and larger, and the canals vanish. 

 When the space has reached its full size, it remains 

 for a short time and then suddenly vanishes. The 

 sequence of events, as well as the rhythm, remind 

 one forcibly of the cardiac cycle. In a Vorticella the 

 time occupied from systole to systole was about half 

 a minute.* 



There are usually numerous food-vacuoles in the 

 endorsarc, sometimes filled with fluid, sometimes 

 with solid particles. Somewhere near the centre of 

 the cell is a round endoplast with a smaller endo- 

 plastule attached to it. 



The mouth commences in a fold or involution 

 which passes into a short ciliated gullet or oesophagus 

 (Fig. 55^). This last ends blindly in a round sac 

 which, in some views, may easily be mistaken for a 

 large food-cavity. The food enters this sac, drawn 

 in by the action of the cilia, which seem to be con- 

 stantly working. Carmine particles introduced into 

 the water will be drawn into the body in the same 

 way, so that Paramecium does not select its food, but 

 takes whatever may come within the current. How- 

 ever, it makes longer delays where there is most food. 

 The food or particles of matter having entered the 

 dilatation of the gullet become drawn with surround- 

 ing water into the semi-fluid protoplasm, where a 

 food-vacuole is formed. At one time the Infusoria 

 were called Polygastria, because it was supposed 

 that the vacuoles were connected by a delicate canal, 

 and each space formed a stomach. The vacuoles 

 have no such connection with each other, although 

 they may he very closely together. When the film 

 of endosarc separating them becomes too thin, it 

 gives way, and they fuse into one large vacuole. The 

 nutritive material having been extracted from the 

 food, it is expelled at a definite region near the mouth 

 (anal area), but there seems to be no permanent orifice. 



We thus see that Paramecium is a very complicated 

 cell and very different from the Amceba or the cells 

 that form our own tissues. Indeed, in the Ciliata the 

 cell attains morphologically its highest place, and cell 

 differentiation (a process in which the various parts 

 are differently developed for different purposes) is 

 nowhere seen to greater perfection. 



It is not intended to occupy much space in con- 

 sidering the reproduction of Paramecium, but it is 

 interesting to know that it either reproduces itself 

 asexually by simple division of its substance into two, 

 or sexually by the more uncommon process of con- 

 jugation observed and described by Balbiani. 

 (To be continued?) 



" Thirty-two seconds. 



TWO BOG FLOWERS. 



IN the boggy ground that is so frequent upon our 

 mountain sides, there is one little plant that 

 cannot fail to attract the notice of those who wander 

 thither. Its rosette of shining yellowish leaves is 

 closely pressed down upon the mosses amongst which 

 it chooses its home, in company with the sundew, 

 bog pimpernel, asphodel, and such-like moisture- 

 loving plants. If it be the early summer-time, one . 

 or more flowers somewhat resembling the violet in 

 form and colour will be seen, each rising on a long 

 elegant scape from the centre of the rosette o leaves. 

 This is the butterwort (Pinguicula vulgaris), and it is 

 to the peculiar greasy appearance of the leaves that it 

 owes its generic name (pinguis = fat) ; of the com- 

 mon English name, something will be said further on. 

 The plants that compose the order to which it belongs 

 (Lentibularineae) are, for the most part, dwellers in 

 marshes or water, but the only other genus of this 

 order in our country is the bladderwort ( Utriadaria), 

 so named from the little bladder-like pitchers that 

 buoy it up in the water, and possibly serve other 

 purposes not yet satisfactorily defined. The Lentibu- 

 larinere have strong affinities with the Scrophularinese, 

 and these are specially shown in the personate or two- 

 lipped corolla, and the spur of the lower lip as well 

 as in the axile placentation of the ovary, but it has 

 also peculiarities of structure that will appear as we 

 proceed. 



We will first examine the leaves, which are oblong 

 and obtuse, with a broad, short, sheathing petiole. 

 The margins are strongly curved inwards, especially 

 towards the tip, and make the leaf into a sort of little 

 spoon, a form which is said to have its use in detaining 

 small insects, for the consumption of this so-called 

 carnivorous plant ! If a lens be used to inspect the 

 texture of the leaf more closely, we find that it is 

 thickly dotted over with minute oil-glands, which 

 impart the greasiness that is as perceptible to the touch 

 as to the sight. The flower-scape rises erect from the 

 centre of the plant to the height of several inches, 

 and like the leaves is thickly studded with glandular 

 hairs. The calyx is small ; and the five sepals, three in 

 front and two rather longer behind, give it somewhat 

 the appearance of a claw holding the corolla in place. 

 The flower is not unlike a violet at first sight, but the 

 two-lipped corolla is gamopetalous, and a little careful 

 manipulation will bring it off in one piece, when the 

 short tube by which it is attached below the ovary 

 (hypogynous) is to be seen, like a hole cut in the 

 upper lip at the back of the lobes. The lower lip is 

 broad and three-lobed, and the throat is densely 

 covered with a perfect forest of jointed white hairs 

 turning inwards. Looking full into the face of this 

 pretty flower, one can at first see neither stamens nor 

 pistil, so cunningly are they concealed ; but just 

 underneath the upper lip there is something that 

 looks like a fold or scale, and by tearing down the 



