CO LTS'-FOOT COLUBER. 



/lour adopted. If we accept the Newtonian o 

 molecular theory, we must conclude that some change 

 takes place in the size of the particles of the bodies 

 whether hair, feathers, or flower petals, which causes 

 an alteration in the absorption and transmission o 

 the primary rays ; thus in the case of the autumna 

 leaf, when no longer nourished by the usual circula 

 tion of the sap, its particles undergo a change which 

 cause it to absorb the green rays which were before 

 reflected, and reflect the red, orange, or red rays 

 which were before absorbed. To this theory, how- 

 ever, Sir David Brewster does not assent ; he con- 

 siders it probable that these tints are caused by two 

 different juices on each side the plant, which exert a 

 different affinity over the primary rays. " The colours 

 of vegetable life," he observes, "and those of various 

 kinds of solids, arise, we are persuaded, from a specific 

 attraction which the particles of these bodies exercise 

 over the different coloured rays of light." As au- 

 tumn therefore advances, we are to presume that the 

 juices of the leaf change; there is a difference in the 

 secretion, and consequently in the attraction of the 

 primary rays. It must, however, be confessed that 

 this is a mere hypothesis, it is overturning one theory 

 by another equally undemonstrable, for where is the 

 proof that any such affinity exists as is here supposed ? 

 Lastly, if we adopt the undulatory theory, we must 

 conclude that the change of seasons, age, climate, &c. 

 causes such a change in the particles of bodies as 

 induces a greater or lesser frequency in the undulations 

 of the etherial medium, now producing the violet and 

 now the crimson colour. 



However veiled in obscurity may be the laws of 

 light and colour, the different colours which irradiate 

 the world, are of eminent importance in the general 

 economy of nature. The colour of different soils 

 influences their fertility, the darker soils absorb, and the 

 light reflect the solar rays. The varied shades of green 

 presented by grass, herbs, and the foliage of trees, 

 relieves the surface of the earth from a monotony 

 which otherwise would have been painful to the eye. 

 The gaudy plumage of birds in tropical climates pro- 

 tects them from the direct heat of the sun's rays, wnich 

 are reflected from their feathers in brilliant rainbow 

 hues. Animals, which are guided principally by the 

 sense of sight, are attracted to their prey by the colour 

 which now exposes and now conceals them from their 

 view. The vulture perceives chiefly by its colour its 

 prey at an almost incredible distance; and whales are 

 attracted by their colour to the molluscae on which 

 they feed. The disposition, therefore, of the colours 

 of natural bodies is in strict unison with that harmony 

 of design which is manifested throughout the universe, 

 and which reveals itself, especially to the naturalist, 

 in every path he is tempted to explore. 



COLT'S-FOOT is the Tussilago farfara of Lin- 

 naeus. It is a medicinal herb, and a very troublesome 

 weed to the farmer of damp clayey land. The flowers 

 come forth early in the year, and long before the 

 large roundish leaves. Deep and repeated ploughings 

 in the spring months is the only method of destroying 

 the roots and preventing it spreading. 



COLUBER, a genus of ophidian reptiles, belong- 

 ing to the division of true serpents which are not 

 venomous ; and exceeding in number any other genus 

 of the order, and, indeed, every genus of reptiles. 

 They are of course without fangs or moveable teeth 

 adapted for inserting poison into wounds ; and, there- 

 fore, they are either simply swallowing serpents, or 



crushing serpents, according to their size and strength- 

 They have large plates on the belly, and a double row 

 of plates on the under side of the tail, by which they 

 are readily distinguished from the poisonous serpents ; 

 but the number of species in the genus itself is so 

 great, and the distinctions between some of them are 

 so slight, that they can hardly be brought into any 

 intelligible order without a degree of minuteness of 

 detail, which is quite incompatible with the nature of 

 a popular work ; and which, though it could be accom- 

 plished, would be of little value to any but those who 

 make this very difficult class of animals a particular 

 study. 



In disposition and habits they all very nearly re- 

 semble each other ; but they differ greatly in size, in 

 strength, and consequently in the sort of prey on 

 which they live. Their head is generally flattened, 

 of an elongated oval form, having the muzzle blunt 

 and beset with a few tubercles ; the head is covered 

 with large plates, about nine in number. Their tongue 

 is forked, and they move it with great celerity ; and 

 from this probably has arisen the vulgar notion of the 

 tongues of serpents being darts with which they can 

 inflict envenomed wounds ; which notion, though it 

 has found its way pretty largely into figurative writ- 

 ing, is of course wholly without foundation. The lips 

 of these serpents are usually covered with scales rather 

 larger than those on the body. The teeth in the jaws 

 are numerous, and generally much hooked, and they 

 assist in the process of swallowing. In some of the 

 smaller species the skin is very tender, but in the 

 larger ones it is correspondingly strong. That of the 

 head and throat, in particular, admits of great exten- 

 sion ; but when the scales are removed, and it is 

 tanned into leather, it is compact and thick, and very 

 durable. The scales upon them all are imbricated, 

 and generally speaking they are lozenge-shaped, and 

 the marks of them give a very peculiar appearance to 

 the tanned skin. 



The whole of the genus are oviparous, and most 

 of them deposit their eggs in the ground to be hatched 

 by the heat of the sun. Those eggs are elongated 

 ovals, with the ends of equal thickness, and covered 

 with a whitish membrane about the consistency of 

 parchment, which is flexible at first, but which hard- 

 ens by exposure to the air. The young, while in the 

 egg, floats in an albuminous fluid, something similar 

 to that which surrounds a chick in the egg ; and it is 

 Furnished with a true umbilical cord, which is attached 

 to the belly a little in advance of the vent. All the 

 species of this genus are understood to change their 

 skins as is the general habit of serpents. 



Both from their form, and the power and vora- 

 city of some of the larger species, these animals lie 

 under the general denunciation which the civilised 

 world appears to have pronounced upon the whole 

 serpent tribe. Whether this arises from the meta- 

 )horical allusion to the serpent, as the symbol of temp- 

 ation in the book of Genesis, it is of little consequence 

 o inquire ; neither is it worth while to go into a 

 brmal refutation of the vulgar notion that serpents 

 walked on feet, before the catastrophe above alluded 

 o ; and that, in consequence of their deceitful con- 

 luct, they were subsequently doomed to crawl on 

 heir belly. We may just remark that a serpent is no 

 more a mutilated creature than any other member of 

 he animal kingdom ; and that, all footless as they are, 

 heir powers of locomotion are, especially in many 

 members of this genus, very efficient and also very 



