AND OF THE PHYSICAL SCIENCES. 



79 



Amono- a quantity of bones collected from ths sa-n? nei^hbourliood with the cra- 

 nium of The Sivathfrium, there are three singularly p2rfi-ct sp.^cimans of the louver 

 portions of the extremities. belon;Tins to three legs of one in.lividaal. Tiicy greatly 

 exceed the size of any known Ruminant, and there is no other ascertained animal of 

 proportionate size excepting the Sivatheriuin. 



BOTANY. 



GENERAL REVIEW OF THE VEGETABLE KINGDOM NO. IV. 



The pr>ncipal causes -.vhich induce this progression of changes are three; 1st, 

 the excess of duration in the winters, a consequence of the obliquity and disappear- 

 ance of the solar ravs; 2d, the dryness of the air, a consequence of the decrease of 

 beat; 3d, the prolonged action of the light, which illumines the horizon through the 

 Tthole period of vegetation. It may be proper here briefly to trace the effects of 

 each of these three causes. 



1st, It IS well known that too great a degree of cold, by congealing the sap, oeca- 

 aions the rupture of the vascular system in plants, 3nd thereby destroys them; but the 

 deleterious action of cold is not confined to purely mechanical results; it has been 

 proved that heat is a stimulus that cannot bo dispensed with in vegetation. Many 

 species secrete juices in warmer regions, which arc unknown in their economy in co'dcr 

 climates. The Ash yields manna in Calabria, but loses that faculty as it advances 

 towards the north. The Grape, in the south of Europe, abounds in matter of a sweet 

 quality; in the north, it contains an excess of acid. As long as the organic functions, 

 which depend upon the degree or duration of heat, can be earned on, the Ash and 

 the Vine contmue to grow; they grow even T^hon those functions are performed in- 

 completely, but their growth is stunted. Thry finally disappear at that point where 

 the portion of warmth in the atmosphere, though still equal to prevent the freezing 

 of the sap, is no longer able to stimulate their organs or their frame into action. AH 

 other ve""etab!es, whose dimension and duration subject them to the full severity of 

 the frost, share the same destiny, at a greater or less distance from the tomd zone, 

 and in proportion as their constitutions require a greatei or less degree of heat. So 

 that nothing is found ntar the Pole but such dwarf shrubs as are sheltered under tho 

 snow in winter, or annuals and herbaceous species, endowed with so quick a principle 

 of life, as to rise, flower, and fruit within the space of three months; or some aga- 

 mous and cryptocamous speeies, which adapt th'*msclves to all degrees of temperature, 

 and are consequently the last organic forms under which vegetable life is to be 

 (iescried. 



2d, Heat and moisture are highly favorable to the growth of plants. No countries 

 are more abundant in herbaceous vegetables, or better wooded, than Senegal, Guinea, 

 and Cayenne, where both these props of vegetation are m the plenitude of their force. 

 Experiments made with the hygrometer prov*^ that the moisture of the atmosphere 

 increases as we approach the Equator. In hot climates, when the sun sinks below 

 the horizon, the watery exhalations condensed are returned to the earth in the form 

 of dew, that moistens the surface of the foliage, and feeds those vegetable* in which 

 the absorbing powers of the parts above ground sutlicc for their support. Of this 

 number are the succulent plants; the Aloes, the Cactiy the Mcsembrynnthemnms-, 

 some of the Spurges, &c. In these the fibrovis root only serves to hold them in their 

 places; and the moisture of the atmosphere is inhaled and retained by the spongy parts 

 above. Thus, in the vast plains that receive the waters from the eastern declivity of 

 the Andes, when the scorching heat of summer has consumed the grasses and other 

 herbaceous kinds which the rainy season had brought forth, we still find some linger- 

 ing Cacti, which, under their dry thorny coats, conceal a cellular system, by which 

 an abundant sap has been imbibed and preserved. But in countries where the aimo- 

 spbere holds but little moisture in evaporation, either because the soil is wholly desti- 

 tute of water, or by reason of the coldness of the temperature, we find no plants at 

 all, or such only as are of dry, hard texture. The sands of Africa, watered by no 

 river, are found to be utterly barren. Spitzbergen, Nova-Zembla, Kamschatka, &c. 

 where the influence of the sun is only felt for two months in the year at most, and 

 where, consequently, the air is habitually dry, furnish a very scanty portion of herba- 

 ceous only, or some dwarf shrubs, with a narrow leathery foliage. It is true that 

 drought is not in these instances the sole cause of the degenerated state of vegetation, 

 but it would of itself be sutiieient to produce it; for it is a fact, that plants acquire 

 height of stem and breadth of foliage only in proportion to the abundance of nutriment 

 which they meet with in the atmosphere, and that nutriment is water reduced into 

 vapour, and held in suspension by the atmosphere. 



3d, When vegetables are depiived of light, they extend in Ungth, shoot up pale 

 lank stalks, are of a lax fibre, and of no substance ; in short, th<;y spindle themselves 

 out. The way that light acts upon this class of the creation is principally in sepa- 

 rating the elementary parts of the water and carbonic acid contained in them, and in 

 extricating the oxygen of the latter. The carbon of the acid, with the hydrogen and 

 oxygen of the water, form the bases of the gums, resins, and oils, which flow in the 

 vessels or fill the cells. These juices nourish the membranes, and induce the woody 

 state in them; and they do this in proportion as the light is stronger, and its action 

 more prolonged. Thus we see that darkness and light have eflfects directly opposite 

 upon vegetables. Daikness favors the length of their growth, by keeping up the 

 pliancy of their parts; light consolidates them, and stops growth by favoring nutri- 

 tion. It should follow that a fine race of vegetables, one that unites in due propor- 

 tion size and strength, depends in part upon the proper reciprocation of nights and 

 days. Now, in the northernmost regions, plants go through all the stages of growth 

 at a time when tho sun no longer quits the borizrn; and the light, of which they ex- 

 perience the unremitting effect, hardens them before they have time to len"then. 

 Their growth is quick, but of short duration ; they are robust, but under-sized. 



The same plants when transplanted into milder regions, where the atmosphere is 

 moist, and light and darkness follow in regular succession, are seen to lengthen their 

 stems, expand their branches, as well as multiply, dilate, and soften their leaves. 

 They must, however, be endowed with a frame of sufficient pliancy to support their 

 new mode of existence. 



Etfects of ^louMTAiN HEIGHTS OS PLANTS. — DuHn^ the recent interesting 

 tour made by M. Gay among the Cordilleras, hn discovered many beautiful and rare 

 specimens of Buccliaris, l.oana, Ahtrteuwria, and above atl, those charming flower?, 

 the Mvthiny which exhibit the most singular phenomena. As the tendrils with 

 which these plants are usually furnished would beco;ne useless in these cold regions, 

 unprovided with shrubs or bushes, they are chani^ed into leal leaves, organs of sui-h 

 great utility to mountain plants. He also remarked, that thi; plants which are herb- 

 aceous in the plains, become heie entirely'li_;neous ; and that several trees, especially 

 the Esc.dfonia^ instead of assuming that forked appearance which characterises it, 

 becomes stunted, creeping along the rocks, and thus oifering less suiface to the cold 

 with which the wind is charged in passing over the^e nuir.erou? and immense gkiciers. 

 But another observation, which he also made among these culd regions, is still more 

 interesting ; it is the form of imbrio;ited leaves which the greater portion of the vege- 

 tables assume, among those generally even whose habitual form seems to be entirely 

 contrary to this disposition; thus the leaves of the Ti iplUitm, which are so lax and 

 small in the lower regions, become hero extremely hard and tough, closely imbricat- 

 ing the stalks, and even the flowers of these beautiful plants. The Mutulay which 

 is nearly devoid of leaves when at the side of mountains, produces at their summit a 

 considerable number. The violets here have not that elegant forri, wliit.h is ob- 

 served m those flowers lower down, but possess a conformation altogether different ; 

 they have the appearance of a rosette, which may be compared to that of a Seduniy 

 with this difference, that the haves, instead of being almost vertical, are in these al- 

 pine violets entirely horizontal. These leaves, which are extremely hard and tough, 

 are round, scabrous, strongly imbrieatcd. and exhibit at the footstalk flowi rs which 

 are sessile, and of a violet colour somewhiit approaching to red. Although M, Gay 

 was very familiar with the genera Tiiptilion, E&caleonicij Muthia, and I'iola^ the 

 particular aspect of these alpine species caused him to mistake them entirely, nor 

 did he discover to what genus they belonged, until he studied them after his re- 

 turn. 



On the BEDEGUAn of the Rose. — Mr Jesse makes the following observations 

 on this subject : — " 1 have often admired a small, round, mossy substance attached to 

 a branch of the Dog-Rose growing in our hedges, and which 1 was unable to account 

 for until the following circumstance was related to me by an ingenious florist and 

 nurseryman in the King's Road, Chel?ea, Loiulon, Mr Knight, who informed me, 

 that, having been requested by one of his customers to endeavour to preserve a fa- 

 vorite niuiberry tree, which for many years had flourished on her lawn, but which, 

 with the exception of one very largo branch, was either dead or decaying, he waited 

 till the sap was ascended, and then banked the bianch completely round near its 

 junction wiih the trunk of the tree. Having filled three sacks with mould, he tied 

 them round that part of the branch which had been barked, and by means of one or 

 two old wateiing-pots, which were kept filled with water, and placed over the sacks, 

 from w.iicli the water gradually distiih'd, the mould in the sacks was sufficiently 

 moistened for his purpose. Towards the end of the year he examined the sacks, and 

 found them filled with numerous small fibrous roots, which the sap, having no longer 

 the bark for its conduetor into the main roots of the tree, had thus expended itself in 

 throwing out. A hole having been prepared near the spot, the branch was sawn off 

 near the sacks, and planted with them, the branch being propped securely. The 

 next summer it flouiished and bore fruit, and is still in a thriving state. 



" Having heard lids fact. I ex;-mined the mossy substance on the Dog-Rose, and 

 found that, in consequence of the baik on the branch on which it was found having 

 been removed by some insect, the sap in receding had thrown out roots, which, 

 from the exposure of the air, pioduced the mossy ball in question, and which was 

 probably made the nest or hybcrnaculum of some insect. If this mossy sub- 

 stance be examined, the larva of an insect will be found belonging to the j^enus 

 Cynips." 



On the Structuue of the Radish Root. — It is well known to most observers, 

 that at the s-ummit of the root of the common radibh, at the very base of the stem, 

 or that place which the French call the collet^ the English the ncch, is an 3ppend2.ge 

 at first resembling a membraneous sheath, enwrapping the yfung root, and subse- 

 quently, as the root distends, becoming two loose straps hanging down en each side of 

 the loot. The nature of this appendage was unknown, until the late L. C. Richard 

 discovered the existence of two modes of germination, called the exo-rliizal and eiidv- 

 Thizal, and suggested that the radish was an example of the latter mode, a notion 

 which has been generally admitted by recent writers, notwithstanding the circum- 

 stance, that if endo-rhizal, the radish would ofi'er an exception to a very general law, 

 that endo-rhizal germination goes along with the indigenous growth. M. Turpin 

 has lately demonstrated that the sujtposed fleshy root of the radish belongs to the 

 ascending axis, not to the descending one, and that consequently it belongs to the 

 system of the stem, and not to that of the root. Ho further asserts, that the tu- 

 mour, which ultimately becomes the radish, is in the beginning cjlindricat, and that 

 its cuticle loses at a very early period the power of distension; in short, that it dies, 

 and separates from the subjacent living matter, just as dead bark separates from 

 liber and young wood in old stems. Now this premature death of the cuticle is 

 connected with the rapid lateral distension of the tumour, the caure of the existence 

 of the two appendages in question, which are nothing more than two straps of dead 

 cuticle, rent asunder by the gradual but rapid distension of the part that they origin- 

 ally ensheathed. 



On the Matehials of Lechork akd Tuscan Bonnets. — There has been 

 considerable controversy as to the plant from which these bonnets arc manufac- 

 tured. I\I. jMerat, M.D. in a letter to the Editor of the Archives de Bolanique, 

 says, "This gramineous plant is a genuine Wheat (^Tniicvm)^ and net a Rye 

 (5ccaZe), as M. Chaubard terras it. It is a summer corn, a sort of spelt. It is 

 sown in the spring in barren ground, in a dry soil, and cut down before the es- 

 pansion of the car. The entire straw (^SommiUs) is employed, after having first 

 bleached in the dew, and afterwards by a chemicul process. There are lands which 

 produce superior straw to others, and of which the middle boles {cfufre naeudit) 

 are longer, a circumstance which is particularly desirable. The same fields in France 

 do not produce such good straw, although the grain answers weU." 



