222 



CUTANEOUS SYSTEM. 



lent emotions, fear, fright, or anger, they are observed 

 to become erect. This is caused by a muscular web, 

 which lies below the skin, and is called the panni- 

 culus carnosiis, the fibres of which in contracting force 

 the hair into an erect position. It is well seen in 

 dogs and cats. It commands, also, the erection of the 

 quills of the porcupine, and the spines of the hedge- 

 hog. The colour of the hair of many quadrupeds, 

 like the plumage of birds, changes at certain seasons 

 of the year. The summer dress of the Alpine hare 

 (Lepus variabilis] is of a tawny grey colour ; as winter 

 approaches, it gradually changes until it becomes 

 snow white. The ermine, which frequents the out- 

 skirts of woods and thickets during summer, is of a 

 pale reddish brown colour ; in August it becomes 

 clouded with pale yellow, and in November it is snow 

 white. As spring returns the white becomes mottled 

 with brown spots, and in the month of May its sum- 

 mer garb is resumed. The hair even of the human 

 body is somewhat lighter in winter than in summer. 



WOOL is a cutaneous appendage which differs in 

 no respect chemically from hair ; it is, indeed, gene- 

 rally described as hair short and crisped. It differs, 

 however, from hair, in being finer in texture and in 

 growing more uniformly. Each filament of wool 

 grows at equal distances, and if not shorn, all the fila- 

 ments separate nearly at the same time from the skin, 

 for the wool completes its growth in twelve months, 

 and is then shed. Another peculiarity is the diffe- 

 rent degree of thickness which prevails in the wool 

 on various parts of the same animal, besides the fila- 

 ments are closer at their extremities or points than at 

 their roots. Furthermore, the fleece which grows 

 during winter is of much finer quality than that which 

 is produced during summer. The physical qualities, 

 however, of wool, are considerably affected by the 

 soil on which sheep feed. It has been shown by Mr. 

 Bakewell that the herbage of each district derives 

 from the difference of soil peculiar properties, which 

 when taken as food, have the power of affecting that 

 process of the animal economy by which wool is pro- 

 duced. Accordingly, the wool of sheep pastured on 

 chalk districts, or light calcareous soils, is hard and 

 harsh to the touch ; the wool of those pastured on 

 rich loamy argillaceous soils, is always distinguished 

 by its softness. The soils most favourable to the soft 

 quality are, first, the argillaceous, and next, the sili- 

 ceous ; the calcareous, whether limestone or chalk, 

 produces wools of a contrary quality ; so that in pro- 

 portion as these earths preponderate in a loose state 

 near the surface of different soils, their effect may be 

 detected, whatever be the breed of sheep from which 

 the wool is shorn. If the weather be fine, sheep in 

 this country are shorn in the month of June, although 

 some farmers delay the operation until July. The 

 wool in the state first shorn is called fleece, and each 

 fleece is usually separated into three sorts : 1, mother 

 wool, or that of the back and neck ; 2, the wool of 

 the tails and legs ; 3, that of the breast and under the 

 belly. This classification corresponds with the Spa- 

 nish method of sorting into rafinos, or prime ; finos, or 

 second best, and terccras, or inferior sort. Till within 

 a few years, the finest wool was imported from Spain ; 

 but next to Spanish sheep, the Ej^lish yield the 

 finest wool that can be introduced into the market. 



BRISTLES and SPINES are modifications of hair ; 

 in the former the hair is stiff, in the latter inflexible. 

 The bristles growing upon the back of the hog and 

 wild boar form a considerable article of commerce, 



being extensively used by brushmakers, shoemakers, 

 saddlers, &c. They are imported into this country 

 from Russia ; those of Ukraine being held in the 

 highest estimation. 



HORN is a substance analogous to hair, and has, 

 indeed, been identified with it. When the horn of 

 an ox is examined, it is found to consist of fibres which 

 run parallel with each other from the root to the point 

 of the horn, sweeping along the course of whatever 

 curvature it may describe. Their disposition, how- 

 ever, varies. Instead of being straight and sweeping, 

 these fibres in the horn of the ram present a waved 

 or undulated appearance. Hence the substance of 

 horn appears to be made up of a conglomeration of 

 hairs ; but this is not always the case, for the horns of 

 the camelopard arid stag are truly osseous. It would 

 appear, indeed, that horn differs from bone in this, 

 that horn is composed principally of animal matter 

 intermixed with very little phosphate of lime or other 

 earthy matter, while bone consists principally of phos- 

 phate of lime with very little animal matter. The 

 density and compactness, therefore, of the horn, de- 

 pends on the quantity of earth or animal matter en- 

 1 tering into its composition. The horn of the rhino- 

 ceros is purely a cartilaginous or horny substance ; 

 here the animal matter predominates ; the horn of 

 deer is purely osseous, in this case the earthy matter 

 predominates. Horns are in most animals to be re- 

 garded as weapons of attack and defence ; and as 

 such they are instinctively used ; hence young cattle 

 are observed butting with their head months before 

 their horns appear. 



The manner in which the horn is developed is as 

 follows : immediately below the skin, and over the 

 frontal bone, two tubercles may be seen in the young 

 calf. These gradually become more callous, and en- 

 large in size, shooting out conically. This growing 

 horn consists of three parts, an external sheath or 

 prolongation of the cuticle, a vascular investment, and 

 an internal osseous substance. The vascular mem- 

 brane has two different powers of production at each 

 surface ; the internal supplies the phosphate of lime ; 

 the external deposits layers of horny substance. 

 When three years old, the horn is smooth and hand- 

 some ; afterwards its annual growth is marked by a 

 circle or wrinkle at the base ; and, according to the 

 number of these, the age of the animal may be deter- 

 mined. Horns, however, do not always grow from 

 the frontal bone ; in the rhinoceros they proceed from 

 the nasal bone, and in many other animals they arise 

 immediately over the ridge of the occipital bone. In 

 some species, as the stag, the male only has horns ; 

 and, generally speaking, as in the case of the goat, 

 where both male and female have horns, the female 

 are smaller than those of the male. The horns, how- 

 ever, of the bull are shorter and denser than those of 

 the cow. Between the size of the horn and bulk of 

 the animal there is no correspondence ; some small 

 breeds of cattle have very large horns, while some 

 good-sized cattle, as the Yorkshire-polled cattle-, have 

 no horns at all. Horns vary remarkably in shape 

 and size. The horns of the goat are rough, angular, 

 and bent retrally ; those of the red deer are branched, 

 round, and recurved. The roe possesses horns which 

 are round and erect ; the fallow deer horns pal mated 

 at the top. The length of the horn varies conside- 

 rably. Cattle with long horns are said to excel in 

 their hide, hair, and the quality of beef; those with 

 short horns in the quantity of the beef, tallow, and 



