Jan. 27, 1882.] 



♦ KNOWLEDGE • 



261 



PLAINLTWoRDED -EXACT&DESCRIBED 



LONDON: FRIDAY, JANUARY 27, 1882. 



Contexts of No. 13. 



PAGE 



Hyacinth Bulbs. By Grant AlU-n iOl 

 Brain Troubles : Partial Loss of 



Speech 262 



Dr. J. W. Draper. By the Editor. 



{IVilka Portrait.) 263 



The ereat Pvramid. By the Editor 



(Illiutrated) 26.5 



The True Storv of the Moon 268 I 



Babylonian Discoveries. By a Mem- 

 ber of the Society of Biblical I 



Archneologv .'. 263 i 



Intelligence 'of the House Martin. ! 



By Uenrj- J. Slack 269 



Intelligence in Animals 269 



Ghosts. By Andrew Wilson 269 . 



Arlilioial Indigo 



Science and Religion 



CoRRBsposDESCB : — Chinese Calcu- 

 lation—Mind ; Doctors— Sea Ser- 

 pent or Seaweed?— Marine Boilers 

 —Intelligence in Animals— Elec- 

 trical Images — Mortality from 

 Cancer — Arranged Squares, Ac. 272 



Queries 



Kepli. 



Answ 



Xol 



to Queries 



s to Correspondents . 



^a on ,\rt and Science . 



Our Mathematical Column . 



Our Chess Column 



Our Whist Column 



HYACINTH BULBS. 



Bt Grant Allex. 



IF we were not so familiar with tlie fact, we would think 

 there were few queerer things in nature than tlie 

 mode of growtli followed by this sprouting hyacinth liulb 

 on my mantelpiece here. It is simply stuck in a glass 

 stand, tilled with water, and there, with little aid from 

 light or sunshine, it goes through its whole development 

 like a piece of organic clockwork, as it is, running down 

 slowly in its own appointed course. For a bulb does not 

 grow as an ordinary plant grows, solely Viy means of carbon 

 derived from the air under the influence of sunlight. 

 What we call its growth we ought rather to call its un- 

 folding. It contains within itself everything that is neces- 

 -;uy for its own vital processes. Even if I were to cover 

 . up entirely, or put it in s. warm, dark room, it would 

 -prout and unfold itself in exactly the same way as it does 

 hei-e in the ditfused light of my study. The leaves, it is 

 true, would be blanched and almost colourless, but the 

 flowers would be just as brilliantly Ijlue as these which are 

 now scenting the whole room with their delicious fragrance. 

 The question is, then, how can the hyacinth thus live and 

 i;row without the apparent aid of sunlight, on wliich all 

 M'getation is ultimately based? 



Of course, an ordinary plant, as everybody knows, 

 derives all its energy or motive-power from the sun. The 

 green leaf is the organ upon which the rays act. In its 

 cells the waves of light propagated from the sun fall upon 

 the carbonic acid which the leaves drink in from the air, 

 and by their di.sintegi'ating power, liberate the oxygen 

 while setting free the carbon, to form the fuel and food- 

 stuff of the plant. Side by side with this operation the 

 plant performs another, by building up the carlxm thus 

 olitained into new combinations with the hydrogen obtained 

 ■■■m its watery sap. From these two elements the chief 

 ustituents of the vegetable tissues are made up. Now 

 lilt- fact that they have been freed from the oxygen with 

 which they are generally combined gives them energy, as 

 the physicists call it, and, when they re-combine with 



oxygen, this energy is again given out as heat, or motion. 

 In burning a piece of wood or a lump of coal, we are simply 

 causing the oxygen to re-combine with these energetic 

 vegetable substances, and the result is that we get once 

 more the carbonic acid and water witii wliich we started. 

 But we all know that such burning yields not only lieat, but 

 also visible motion. This motion is clearly seen even in 

 the draught of an ordinary chimney, and may be much 

 more distinctly recognised in such a machine as the steam- 

 engine. 



At first sight, all this seems to have \<iy little connec- 

 tion with hyacinth bulbs. Yet, if we look a little deeper 

 into tlie question, we shall set; that a IniUi and an engine 

 have really a great many points in common. Let us glance 

 tirst at a somewhat simpler case, that of a seed, such as a 

 pea or a grain of wheat. Here we lia\c a little sack of 

 starches and albumen laid up as nutriment for a sprouting 

 plantlet. These rich food stuffs were elaboratetl in tin- 

 leaves of the parent pea, or in the tall haulms of the 

 growing corn. They were carried by the sap into the 

 ripening fruit, and there, through one of those bits of vital 

 mechanism which we do not yet completely understand, 

 they were selected and laid V)y in the young seed. When 

 the pea or the grain of wheat begins to gtnniinate, under 

 the influence of warmth and moisture, a very slow com- 

 bustion really takes place. Oxygen from the air combines 

 gradually with the food stuff's or fuels — call tluMU ^hich 

 you will — contained in the seed. Thus lieat is evolved, 

 which in some cases can be easily measured with the ther- 

 mometer, and felt by the naked hand — as,for example, in the 

 milting of barley. At the same time motion is j)i-oduced : 

 and this motion, taking place in certain regular directituis, 

 ie;ults in what we call the growth of a young plant. In 

 different seeds this growth takes different forms, but in all 

 alike the central mechanical principh; is the same : — certain 

 cells are raised visibly above the surface of the earth, and 

 the motive power which so raised them is the energy set 

 free by the combination of oxygen with their starches and 

 albumens. Of course, here, too, carbonic acid and water 

 are the final products of the slow combustion. The whole 

 process is closely akin to the hatching of an egg into a 

 living chicken. But, as soon as the young plant has used 

 up all the material laid by for it by its mother, it is com- 

 pelled to feed itself just as much as the chicken when it 

 emerges from the shell. The plant docs this by unfolding 

 its leaves to the sunlight, and so begins to assimilate fresh 

 compounds of hydrogen and carbon on its own account. 



Now it makes a great deal of dirterence to a spnniting 

 seed whether it is well or ill provided with such stored-up 

 food-stuffs. Some very small seeds have hardly :iny pi'o- 

 visions to go on upon ; and the seedlings of these, of 

 course, must wither up and die if they do not catch the 

 sunlight as soon as they have tirst tiufolded their tiny 

 leaflets ; but other wiser plants have learnt by (-xpterience 

 to lay by plenty of starches, oils, or other useful materials 

 in their seeds ; and wherever such a tendency has once 

 faintly appeared, it has given such an advantage to the 

 species where it occurred, that it has been increased and 

 developed from generation to generation through natural 

 selection. Now what such plants do for their oflspring, 

 the hyacinth, and many others like it, do for themselves. 

 The lily family, at least in the tempenite regions, seldom 

 grows into a treelike form ; but many of them have 

 acquired a habit which enables them to live on almost as 

 well as trees from season to season, though their leaves die 

 down completely with each recurring wintci-. If you cut 

 open a hyacinth bulb, or, what is simpler to experiment 

 upon, an onion, you will find that it consists of several 

 short abortive leaves, or thick fleshy scales. In these sub- 



