Till-; HISTORY OP ART. 



243 



. which la perforated by the mouth of the animal. Another 



.f larger size is situated on t!i<> umlur MUK of the body, 



:.vrtor of an inch from the mouth. This in nimilurly 



eoustri, rforato, and does not communicate with 



rnal organ. Locomotion, BO far as it in needed to this 



a effected by these sucker*, whirh can bo alternately 



attached, and also by the general 11 \il>ility of the bodv 



-lor layer bi-:. : ;uin. The UK. nth Ir.id- 



.1 short gullet, below which the alimentary canal 



i:it two main trunks, which run down to the tail-end of 



tin- animal, j-'uin,' off blind branches in a way best explained by 



,'. There is no anas, and this perhaps is not needed, 



unit of the highly organised food which the animal 



ingests. The fluke, however, readily ejects the food from its 



<1 stomach, by curling itself up like a little strip of 



parchment, and thus squeezing it out. Another system 



Is has a single opening towards the tail of the body, 



and runs forward, giving off bronchos on either side, and thea, 



i has arrived at a distance of about one-third of the 



of the animal from the oral sucker, it splits into three 



bronchos. This system corresponds with the water-vascular 



system of the Tcwita. 



Thi-t animal is hermaphrodite, that is, it has both male and 

 female organs. The development of these creatures is peculiar. 

 It is supposed that when the animal containing matured eggs is 

 voided from the sheep, it reaches some moist place or pool of 

 water, and deposits its eggs, which emit a larva which swims 

 about by cilia, and has a single X-shaped eye. This larva fixes 

 on some fresh-water snail and penetrates its skin, and when it 

 has arrived at the interior, is transformed into a large bag or 

 Containing in its interior many tadpole-shaped animals 

 with long tails, called cercanoe. The cercariae once more escape, 

 not only from their foster-parent or nurse, but also from their 

 molluscous host, into the surrounding water, and it is probable 

 that they are imbibed with the water by sheep, and then pene- 

 trate to the liver, causing the rot. In accordance with these 

 suppositions, some of which have been observed not in the liver- 

 fluke, but in nearly allied species, it is found that sheep fed on 

 dry hind or on the great salt-water marshes are comparatively 

 free from rot, while those fed up in fresh-water marshes are 

 peculiarly subject to it. The disease associated with these 

 creatures is of considerable economic importance, as in some 

 years it has been reckoned that between one and two millions 

 of sheep have died of the rot in Britain alone. 



Besides the flukes there is another sub-class of Helmintkozoa, 

 called Ccelelnvintha, or hollow-bodied worms. These have ali- 

 mentary canals of the same type as the higher animals, being 

 tubes within tubes. The alimentary canal consists of a strong 

 oesophagus, a dilatation or bulb containing a comminuting appa- 

 ratus, or gizzard, and then a stomach continued into an intestine. 

 These creatures ore not hermaphrodite, but the individuals are 

 mole and female. Some of these animals are not parasitic at all, 

 and some of them only under certain circumstances. Thus, there 

 is found in the tropical regions of Asia and Africa an intoler- 

 able pest, called the Dracwnculus Medinensis. This trouble- 

 some parasite is always the female, and it gains access to the 

 body from water through the skin, and then grows and emits 

 its brood, to the great annoyance of its host, often occasion- 

 ing death. When it reaches its full size it is many feet in 

 length, though only fj, of an inch in thickness. It will migrate 

 beneath the skin from one part of the body to another. Some 

 have supposed that these animals were the fiery serpents which 

 attacked the Israelites in the wilderness. The only remedy 

 seems to be to out down to the worm, and having got hold of 

 one end this is wound round a piece of stick. When tuas 

 secured the stick is left for a day or two, and then more of the 

 worm's body is drawn out, and a further winding takes place, 

 and so on until the whole is extracted entire. If the worm 

 be broken, as it swarms with eggs, all the bad effects take 

 which would necessarily ensue if the creature were left 

 lolested. 



The class Helminthozoa show, by their development within 

 ciliated larval forms of utterly different form from the adult 

 animal, by the possession of a water-vascular system, and a 

 radial structure of their head-organs, an affinity for the Echino- 

 dermata. On the other hand, their elongated and transversely- 

 striated or segmented forms, as well as the position of the 

 scanty representatives of the nervoua system, show on approach 



to the annelids or true worms. Doubtless they lie between these 

 classes ; but whether they are so much more nearly associated 

 with the first- named as to be properly placed with them in 

 separate sub-kingdom, called Annuloida, may be doubted by 

 some. 

 The class may be thus divided into sub-classes and orders: 



OlOUt S'ib-claxf, 



Cestoda = tapeworm. 

 Acantho oephala = thorn- 

 headed worm. 



HLLMI.VTH 



I. Anentorelmintha 



II. Sterehnintha 

 III. Ccolelmintha 



{a Turbell&ria : non-pamntie. 

 4. Trematoda = fluke*. 

 5. Nematoda = round worms. 



THE HISTORY OF ART. 



IX. LIONABDO AND THE FULL RENAISSANCE. 



THE end of the fifteenth century and the beginning of the 

 sixteenth form the high tide of art in Italy. It was then that 

 the last trammels of mediaeval feeling were cast aside, and the 

 Italian mind rose to its greatest achievements, in a way which 

 it has never yet equalled, far less surpassed. The reasons for 

 this change are too vast to be fully described in a brief sketch, 

 but some small attempt may yet be made to account for it in 

 part. 



All through the Middle Ages, Italy, we have seen, had a far 

 freer, wider, more cosmopolitan type of life than any other 

 European country. Florence, Rome, Milan, Venice, Genoa, 

 were all the centres of great mercantile enterprises and civic 

 polity at a time when the remainder of Europe was still deeply 

 steeped in feudal militarism. Towards the close of the fifteenth 

 century, however, the civilisation of Italy, long growing and 

 increasing in the comparative peace of the mercantile peninsula, 

 reached its culminating point. The Mediterranean was still 

 the great highway of commerce, and Italy still held all the keys 

 of the Mediterranean. In the next century the discovery of 

 America and of the route to India by the Cope of Good Hope 

 was destined to revolutionise the whole state of Europe to 

 turn the world westward towards the new-found countries, 

 instead of eastward towards the old civilisations, and so to 

 transfer the really important harbours and trading-places of 

 the European culture from the Adriatic or the Tyrrhene Sea to 

 the Atlantic coast. As yet, however, Italy retained the first 

 place, and the steady increase of wealth and knowledge through, 

 out five centuries was followed by a steady improvement in art 

 as well. 



One peculiar fact which had a great deal to do with the rise 

 of the Renaissance feeling in Italy was certainly the fall of 

 Constantinople to the Turks in 1453. After that event, many 

 of the learned Greeks retired to Italy, where they introduced 

 much of the ancient Greek literature, which had long been lost 

 in the west, and especially the works of Plato. But single 

 causes of this sort, though important in their way, had doubt- 

 less less to do with the great wave of feeling which was slowly 

 passing, first over Italy, and then over the rest of Europe, 

 than the general growth of peace and industrial life. Men 

 were beginning to have leisure to think for themselves to 

 move a little outside the fixed grooves of mediaeval beliefs and 

 conventions. In the social world, the change is seen as the 

 decay of feudalism ; in the religious world, it is seen as the 

 Protestant Reformation ; in the world of thought, it is seen as 

 the revival of learning ; in the artistic world, it is seen as the 

 Renaissance. There was, in fact, a general uprising of the 

 public mind everywhere against the petty, narrow, confined 

 views and habits of the strictly military Middle Ages. 



The great distinguishing characteristic of the Renaissance in 

 Italy is its extraordinary boldness, freedom, and vigour. The 

 new world of thought which was opening up before the eyes of 

 men seemed to turn their heads, almost, in the first flush of 

 liberty, and to make them look upon nothing as sacred, nothing 

 as settled, nothing as certain A reaction from the dogmatic 

 utterances of the Roman Catholic Church made the thinkers of 

 Florence into the boldest sceptics and speculators, ready to 

 inquire about the underlying truths of the universe, and to 

 take nothing for granted in any way. A grand outburst of 

 originality was the result of the new free spirit abroad in Italy; 

 and this originality was not confined to any one department of 



