411. 



KNOWLEDGE 



[Makcii 24, 1882. 



lobos to the corolla, produced by the coalfsconco of the 

 throp pctftls wit)i the thr<>c sepals, so os to form a single 

 unit4d tiilio. Tho olijoct of this coalfsccnoc is easy enough 

 to understand. As in the harel.ell, tho daisy, and so many 

 other flowers, it has heen olFeeted by tho selective ogency 

 of hunihleliees and other insects, like the one whom I 

 found huried so deeply in its throat this morning. 'I'lie 

 tuhular form, with its stamens lian;,'ing out from 

 tho side, ensures tho fertilisation of tho flower much 

 lietter than the system of open petals ; ond so it lias been 

 brought about by the fact that uny variation in that direc- 

 tion was \niconsiiously favoured by tho insects, while 

 variations tho other way were universally neglect«^'d. IJut 

 while many other plants have hit upon this same device of 

 coalescence, few liave carried it so far as the daflbdil. In 

 tho lir-st place, the tube in the ti\c rayed flowers is formed 

 out of the petals alono ; but in the threo-rayod flowers, the 

 petals arc too few in number to make a sufficiently wide 

 tube, and .so the sepals or calyx-pieces are joined with them 

 in producing tho desired result Thus we can trace a 

 gradual progress from flowers like the iris and snowdrop, 

 where the sepals are distinctly dilTorent from the petals, 

 through flowers like the wild hyacinth, lilies, snowflake, 

 and flowering rush, whore all six pieces are equal and 

 simihir, to flowers like tho crocus, meadow saffron, and 

 (lafi'odii, where the six pieces are united together into a 

 long tube. But, furthermore, and in the second place, the 

 datibdil and the others of the narcissus kind have done 

 more than the mere ordinary tubular blossoms, inas- 

 asniuch as they have produced a singular outgrowth 

 in the shape of the crown or cup, which forms, as it were, 

 a vestibule to the tube, and thus still better ensures the 

 proper fertilisation of the flower. In some of the pink 

 tribe (amongst the tive-rayed flowers) we get a scale or 

 par.ipct on each petal in somewhat the same waj- ; but in 

 the daflbdil and its allies the crown is united and circular, 

 like the tube, though one can still trace six wavy lobes or 

 sinuosities on its edge. In some exotic members of the 

 narcissus group the crown is very small and rudimentary, 

 and is brilliantly coloured with red or orange, so that it 

 seems rather to act as a honey-guide for the bees than as 

 an additional aid to fertilisation ; but in the wild English 

 datTodil it has reached a very high state of development, 

 and occup-:es at least half the entire length of the blossom. 

 One word more as to its colour. The daflbdil is a pale 

 yellow, and it apparently depends mainly for impregnation 

 upon the visits of diurnal insects. Hence it is quite scent- 

 less, for its large size and brilliant colour suflice to attract 

 ([uite enough visitors, without any necessity for the extra 

 allurement of sweet perfume. But many of the southern 

 species, like the jonquils of our flower gardens, have pure 

 white petals, and possess a very powerful jasmine odour. 

 Such white, strong-scented flowers always depend, in part 

 at least, upon night-flying moths, which are largely 

 attracted by perfume ; and, of course, no colour can be so 

 well perceived in the dusk of evening as a pure glossy 

 white. Ilencc the difference in hue between the two 

 kinds. At tho same time, tho southern varieties are also 

 fertilised by day-flying bees, and for these the frill of the 

 crown is prettily fringed with brilliant orange. Each 

 insect selects the plant that suits it best, and their joint 

 selection has thus produced the snowy petals and exqui- 

 sitely-coloured cup of the garden jonquil. 



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A STUDY OF MINUTE LIFE. 



I'.v IIknhv J. Slack, F.O.S., P'.R.M.S. 

 No. II. 

 rpilK editor will, it is lioped, allow the writer to explain 

 X that through the accident of his not receiving a proof 

 for correction, many typographical errors appear in the last 

 pa])or. The principal are, " cilian " for ci/intn, " injurious" 

 for in infiigioiia, in the sixth line from the bottom of the 

 first column ; "divided " instead of directed, eleventh line 

 from the bottom of second column ; and " analysis " for 

 aiialoi/i/, eighth line, p. .'(72. 



If we were engaged in tracing life from its simplest 

 modifications upwards, we should now speak of those 

 objects, such as amri^ba-, which are composed entirely of 

 small masses of protojilasm, not built up into any positive 

 structure. Some notice of these is reserved for a future 

 paper, but it is best for the student to begin with objects 

 that can be obtained for certain, without difficulty, and 

 which are easy to observe. It may, however, be mentioned 

 now- that auKoboid creatures, in their ordinary and simplest 

 state, have no permanent distinction of parts. They put 

 forth prolongations and draw them in again ; portions that 

 were outside get inside, as they move on in a slobbery way, 

 and they swallow their food, not through any special aper- 

 ture, but anywhere, by flowing all round it 



It is not uncommon to hear people talk about " homo- 

 geneous protoplasm," but as there is, and can be, no such 

 thing, it is not correct to describe any amoeboid object as 

 composed of it. Life is only manifested by the co-operation 

 of divers matters, highly complex in chemical constitution, 

 and able to perform different functions. The ciliated in- 

 fusoria, of which the Paramecium, spoken of in the former 

 paper, is a good example, is a little bag of skin sufficiently 

 firm to support the cilia, and full of the protoplasmic 

 material. When wo examine this material, wherever it is 

 found in a living state, we see a vast number of particles 

 in a viscid fluid. Their optical aspect suggests that they 

 are not all alike in molecular structure ; and if their ex- 

 treme minuteness did not render it impossible to separate 

 them for analysis, we should find they varied in composition. 

 Lumping altogether, particles and viscous fluid, the con- 

 stituents of protoplasm are found to resemble those of the 

 white of an egg. It belongs to a group of substances 

 found in all living things, and which carry on the chief 

 vital work. Carbon, hydrogen, nitrogen, o.xygen, sulphur, 

 and phosphorus all combine to build up the molecules of 

 this material, and the compound is in a state of such 

 delicate equilibrium that it is easily modified or decomposed. 

 The Paramecium, and similar creatures, take their food 

 in by a mouth, and in the early stages of knowledge con- 

 cerning them, the great German naturalist and micro- 

 scopist, Ehrenberg, thought they possessed a multiplicity of 

 stomachs, because the food particles were dispersed in 

 many little spaces. Their processes of digestion and as- 

 similation are probably carried on without the help of 

 special organs, though, no doubt, the particles seen in the 

 protoplasm have the power of performing different kinds 

 of work. The infusoria will not swallow evcrythintf, but 

 their selective faculty is very small, and they readily take 

 in particles of indigo or carmine, floating in the water 

 about them, although they are of no use to them as food. 

 Microscopists have long been fond of feeding them in this 

 way, as the colouring matters can be traced inside the 

 little animals. The cilia near the mouth bring ail sorts of 

 objects floating in the water towards it, and other cilia 

 make an inward current to suck in what the creatures 

 want. The appearances often seem to support the many- 

 stomached, or polygastric, theory, but the vacuoles in 



