June 15, 18S3.] 



♦ KNOWLEDGE ♦ 



355 



reproduction. He should also ascertain ■whether fish 

 are increasing in numbers, decreasing, or if the supply 

 remains unchanged ; if the size of those captured 

 is augmenting or lessening ; if their condition is better 

 or worse than it was. Should investigations lead him 

 to conclude that fisheries are being unduly depleted, 

 lie should carefully note in what families of lish such is 

 occurring, if possible tlie cause, while in marine forms it is 

 likewise necessary to inquire if fishermen have to go further 

 out to sea to obtain their captures, if the killing powers of 

 their implements have increased, and whether more men 

 are now required to obtain the same amount of fish than 

 was tlie case a few years previously. Lastly, it may l.ie 

 observed, that unless the investigator is able to distinguish 

 the various species, he may easily imagine that he sees in 

 some small forms, as the solonette (Solea niiiiitta), the 

 young of the more valuable kinds, as the common sole 

 ( >'. vu!r/aris), whereas he is merely e.xamining one sort that 

 is worthless, except as food for the larger kinds.'' 



In these pregnant remarks we become aware of the fact 

 that we have to deal with a subject as vast as the universe 

 itself. Inorganic nature plays a passive part in sheltt-ring 

 the denizens of the deep, and it aflbrds nutriment to a 

 varied vegetation which ofttimes sustains them. The 

 flowering plant Virews nectar for the insect which becomes 

 a choice morsel to the finny monster ; and man, most cun- 

 ning of them all, fashions strange imitations to secure the 

 dupe. Interdependence, then, is one of the laws which 

 regulate Dame Xature. 



But we cannot here enter into a detailed consideration 

 of everything which bears both directly and indirectly on 

 our subject, lest our pages should prove too formidable ; 

 we must rather content ourselves with a glimpse at certain 

 typical examples which may be found in the Exhibition, 

 and serve to illustrate the forms of animated creation. 



In the scale of life, plants are popularly regarded as 

 lower types of organisation tlian animals. A little reflec- 

 tion, liowever, will convince one that this is but an erro- 

 neous view of the case, and that the two kingdoms are, in 

 reality, the opposite developments of a common origin. 

 There exists a multitude of forms, not yet thoroughly 

 understood, which occupy a debateable area in the field of 

 creatiorL 



If a small piece of fresh meat is triturated in water, 

 and the strained liquor permitted to stand in a place 

 accessible to the rays of the sun for two or three days, 

 and if into this fluid a few threads of cotton wool are 

 suspended, they (the threads) will be found, in due course, 

 to be coated over with a glairy-looking deposit. It requires 

 a high power of the microscope to reveal what this jelly- 

 like substance is. Professor Huxley has called it protn- 

 plnsm, or the physical basis of life. When magnified about 

 700 or 1,000 diameters, as in Fig. 1., the slimy mass will 



Fig. 1. — Protamaha, from infusion of meat, x 1,000. 

 o, fully grown form; b, undergoing fission; c, divided. 



be seen to move, and soon shows that it is composed of 

 little particles, each endowed with a slowly-creeping motion. 

 The movement consists Ln the protru.sion of rounded lobe- 



like processes, termed pseudopodia* after which the 

 semi-fluid-like body flows, and thus a movement of a 

 characteristic kind results, and is termed amd'oidA 

 Occasionally, one of these little bodies may be observed to 

 divide (Fig. 1, l>, c), and thus to give rise to other indi- 

 viduals ; it is then said to reproduce itself by fission. 



The sagacious naturalist has termed this little speck of 

 jelly rrotHiimia, and says that it is an animal ; this particu- 

 lar J'roliuniiia, however, has not been seen to change into 

 anything else. But what about the thousands of other 

 protanueboid creatures ! Some of them go a stage further, 

 and are then known as Amnhfi; whilst other progress 

 onwards and develop into what are claimed by botanists as 

 plants (My.comyceies). The chief distinction here between 

 vegetable and animal resolves itself into a question of 

 analogy. When the little I'rotamnhn passes through a 

 series of stages which simulate those of t\w undoulited 

 Pandm-iiin, as it does in the case of the Jfi/xomi/c'tes, 

 it may, with safety, be called a plant. On the other hand, 

 ■n^hen its jelly-like body becomes faintly parcelled out into 

 an outer firm (ectoplasm) and an inner .wft (endoplasm) 

 layer, when it develops a dense internal spherical body 

 (nucleus), ingests matter in extempore stomachs (food- 

 vacuoles), and exhibits, in future stages, a dilatable space 

 (contractile vesicle), wliich is supposed to pump its fluid 

 contents tliroughout the sub.stance of the body by a system 

 of obscure canals, then it may probably be an animal. If 

 this so-called animal not only multiplies by fission, f.ut is 

 also observed to become spherical, quiescent, to surround 

 itself with a dense envelope or cyst, and ultimately to 

 liurst and liberate a number of small pro(nmtib/F, which 

 thereafter go through all the stages mentioned above, we 

 are then fully warranted in assuming that it is an old 

 friend, the proteus animalcule, Amelia (Fig. 2), which may 



Fi>r. 2. — Diagrammatic dra^vingB, to show the structure ami de- 

 velopment of Ama>ba. A. Amaiba princeps ; v, villous region; n, 

 nucleus with contained nucleolus ; e, etcoplasm ; e', endopl.-ism ; 

 f, food vacuole ; /, food, a desmid about to be taken in ; <•, con- 

 tractile vesicle. B. Quiescent Amoeba encysted ; c, envelope or 

 cyst ; >i, nucleus, -with nucleolus ; p, protoplasm. C. Liberated 

 AmoebiB from cyst ; c, cyst ; p, protoplasm, now divided into a 

 number of young amoebae sho^vn emerging at a. 



• From the Greek, J/fi'cijc, false ; and TroiJr, ffocdr, foot. 

 t So called from first having been observed in Amoeba, Gr. 

 uniiii), change. 



