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THE EDINBURGH JOURNAL OF NATURAL HISTORY. 



simulating the aspect of plants, they would put on those forms of variation which 

 peculiarly distinguish the vegetable world, consistently, however, with their actual 

 anjmal nature. This is actually the fact. They observe no fixed or precise dimen- 

 sions, although there is a limit to their growth. In numerous instances the figure of 

 the species varies largely. Frequently the shape of some of their parts suffers great 

 variation ; very often specimens of one kind present a variety in regard to colour ; 

 and, lastly, in some, as before noticed, no adherence to any dimension or figure (as a 

 whole or as regards parts), within limits which are allotted to other zoophytes, can 

 be detected, so as to furnish a clue to what might be the prevailing appearance. We 

 shall afterwards see that these forms of variety in the zoophytes are represented in 

 various departments of the vegetable kingdom. 



It must be borne in mind, that although there is a most evident gradual transition 

 from animals to vegetables, the traces of analogy are soon lost in the predominating 

 characteristics of the latter class, and that there are as many differences between ex- 

 treme classes, or departments of vegetables, as are found between extreme classes of 

 animals ; so that it might reasonably be inferred, that a review of the classes of vege- 

 tables of the same nature, such as that we have given to the tribes of animals, would be 

 attended with advantage. Yet, it must also be recollected, that throughout the vege- 

 table kingdom, our knowledge of organization, and consequently our knowledge of the 

 limitations of species, is extremely circumscribed, insomuch, that the science of Botany, 

 as far as regards the determination of species and varieties, is involved in opinion and 

 conjecture. In a review, therefore, of the above named kind, we should be constantly 

 impeded by a want of fixed rules and examples, and we shall content ourselves with 

 an enumeration of such ascertained and determined forms of variety as are met with 

 in this class. 



In the first place, one rule must be stated relative to plants in general, that con- 

 sistently with an increased proneness to vary in proportion as the subject is low in the 

 scale of organization, they display the most extended series of variations, a great por- 

 tion of which assuming too large an amount of difference from the standard structure 

 and appearance, to be regarded as ordinary specimens, have been formally arranged by 

 authors as varieties ; yet, as would naturally be expected, disputes have occurred, first 

 regarding the number of those specimens entitled to be ranked as varieties, and, se- 

 condly, regarding what should be deemed varieties and what species. The vegetable 

 world, then, is a continued scene of variation, and the rule of fixing varieties, tech- 

 nically so termed, is in the highest degree arbitrary and artificial. The most exten- 

 sive mode of variation among plants is that of size and dimensions. The same plant 

 is liable from circumstances, such as soil or station, to sufi'er alterations, in this re- 

 spect, of considerable amount, so that it has frequently been matter of dispute among 

 botanists, whether the most remarkable of these should be esteemed species or varieties. 

 An alteration in size is most commonly accompanied by alterations of other kinds, 

 especially variations in the shape of the whole or of parts, but these also occur inde- 

 pendently of a variety in size. The mode of growth and the habits of plants are sub- 

 ject to variety. A plant commonly erect may be found prostrate, and vice versa. 

 Colour is a mode of variation particularly observable in plants. We here refer more 

 especially to the fio%ver. Frequently there are several varieties in regard of colour in 

 one species. Varieties which affect the structure or organization of the species are 

 extremely common. This is illustrated in a most ample manner by the hair or pubes- 

 cence, a species very frequently havmg varieties with this kind of clothing variously 

 disposed, and in various quantities. The number of styles is not constant in some 

 species of plants ; in Arenaria rubella, for instance, they vary from three to five. 

 In Acer Pseudoplatanus the cotyledons are said to vary from one to four. In those 

 species where the number of any given organ is small, and so far uniform as to furnish a 

 specific character, varieties in respect of such number are sometimes met with. Thus 

 Erigeron alpitms, which usually has but one flower or anthodium on each stem, has 

 two varieties, in one of which the number of flowers ranges from oue to three. Orchis 

 bifolia is occasionally furnished with a third leaf. With the exception of such in- 

 stances as these, flowers, leaves, &c., are numerically unrestricted and undefined. 



As I have before stated, the lowest of vegetable forms enjoy a perfect freedom in 

 regard of size and shape, excepting that a maximum is appointed for the first, and 

 that the shape is at all times in some degree characteristic of the species respectively. 

 I once more repeat, that in this second kingdom of organized beings, varieties obtain 

 to their utmost extent, and that it is an arbitrary proceeding to appoint certain of 

 these variations to be entitled " varieties " in books. In my remarks, therefore, I 

 have not confined myself to these last, but have thought fit to view the subject of 

 varieties in this class as a whole. It remains to be said, that accidental and perma- 

 nent varieties are both met with amongst plants, the former by far the most numerous, 

 and oftentimes found to be constantly liable to reproduction. Permanent varieties 

 are very frequent, as might easily be supposed from the lasting influence exercised 

 oirer vegetable productions by the soil and medium in which they are placed, and 

 these circumstances so prone to alteration within even confined limits. Besides this, 

 vegetables are in very numerous cases endowed with the power of originating forms 

 dissimilar to the stock producing them. Draha verna^ which ordinarily displays a 

 flat pouch, has a variety with a swollen pouch ; Poa alpina has a variety in which the 

 spikelets are densely crowded together ; Lo/htm perenne exhibits great modification 

 in its spike ; Artemisia viantima has two permanent varieties both found growing 

 in the same localities, one distinguished by a drooping, the other by an erect raceme. 

 These differences seem so far permanent and inherent in the plant, that they are oc- 

 casionally seen growing from the same root. We shall return at intervals to the sub- 

 ject of the two kinds of varieties mentioned in this paper. 



Having, in the course of the preceding remarks, enumerated and instanced the se- 

 veral kinds of variation occurring in animals and vegetables, we shall in the next place 

 inquire into the causes and uses of varieties. The uses are proximate and ultimate ; 

 that is to say, either dependent in an evident way on surrounding influences or circum- 

 stances, or produced by some agency, and for some reasons, respecting which we can- 

 not be exactly certain. It is of course easy to refer all occurrences and all produc- 

 tions to the great source of beauty and variety in nature ; but it is the business of the 

 naturahst to search for intermediate causes, even though the search be likely to 

 prove fruitless, and though we should be in danger of setting that down as a cause 



which is perfectly inadequate to the office, whilst the true cause remains hidden, and 

 unadapted to human comprehension. If, however, no cause can be discerned or sur- 

 mised, it is equally the business of the philosopher to ascribe the circumstance to the 

 superintending agency of God ; at least until further discoveries have been made, very 

 many circumstances in connexion with our subject must be disposed of in this way. 



Varieties in respect of size are caused by soil, station, climate, and food. This 

 might easily be conceived, for it is not reasonable to suppose that species disposed to 

 vary should, when their individuals are exposed to adequate causes, continue unaltered 

 in their dimensions. Some species, however, are acted on only by one or more causes, 

 and refuse to be influenced by others though exposed to them. The tendency to 

 variation is not displayed alike by all kinds, not even by species nearly allied. These 

 facts seem of themselves to show that some intention or design, in regard to varieties, 

 pervades nature. Size is perhaps of all kinds of variety the most prevalent or gene- 

 ral, and climate, in co-operation (for the most part} with food, the most usual cause 

 of such diversities. One of the most interesting phenomena in connexion with our 

 subject is that of some natural productions attaining their greatest magnitude, luxu- 

 riance, and vigour, as they approach the tropics. This, of course, can only be ob- 

 served in cases where the geographic range is very extensive. On a small scale, it 

 cannot be expected to be perceptible, unless the stations occupied should present 

 great dissimilarities in climate within confined limits. It might not be easy to cite 

 cases of variety (technically so named) in support of these assertions, but the circum- 

 stance of great variety in size occurring to species is quite sufficient for our purpose, 

 and of this diversity numerous instances can be furnished. The Lion and the Tiger, 

 whose geographic ranges are considerable, attain dimensions near the equator far 

 greater than those which they reach at their furthest limits. The Slow-worm, An~ 

 guis fragilis, attains the length of three feet in countries farther south, and where 

 the heat is more considerable, while with us its usual length is one foot. But be- 

 sides this rule, as regards increase of size, as the species approaches the equator or an 

 increased temperature, there is another law, which clearly shows that each species 

 has its peculiar station at which it enjoys the full vigour of its growth and endowments 

 without regard to heat. The Sea Ear, Haliotis gigantea, in the Polar Seas attains 

 the length of six or seven inches ; but this size, as well as the number of individuals, 

 diminishes as we recede southwards, so that here is a reverse position to that before 

 stated. So also is it with certain kinds of plants. Some are found to degenerate in 

 size as they get into a colder latitude, or are found elevated into the cold atmosphere 

 of a mountain, whilst with others, whose growth is in perfection on the summits of 

 mountains, or in a latitude equally cold, a degeneracy in size can be observed as the 

 species recede from such spots. But, on the other hand, there are instances, as before 

 said, of species resisting almost entirely influences afi'ecting others so freely as occasionally 

 to raise doubts whether they might not be entitled to specific i ank when observed under 

 the extreme of variation to which they have been submitted. The White or Barn 

 Owl inhabits the whole of Europe and America, and yet through this vast extent it 

 exhibits remarkably slight differences. The Wolf also, found from the torrid zone 

 to high northern latitudes^ differs chiefly in the colour of its fur only. 



We occasionally see varieties induced in plants by their being inundated through 

 some accidental cause, in which case the medium (which is equivalent to soil) effects 

 an alteration in their stature or size, besides sometimes producing structural differences ; 

 but I have before stated that plants, beyond all other organised beings, are liable to 

 vary. 



Upon the same principle, that species suffer diminution in size and deterioration 

 generally in their structure and functions, as they recede from the spot at which their 

 maximum of size and utmost luxuriance are attained ; they are found in very many 

 cases to be affected almost in a similar way by the same description of causes acting 

 in the immediate vicinity perhaps of specimens which have attained to their extreme 

 size and full development of parts and qualities. This remark appUes to the lower 

 classes, especially such as are denied the power of locomotion, but coming into exist- 

 ence in an unfavorable soil or station, or where the natural pabulum is furnished spar- 

 ingly, constitute, in the language of naturalists, " dwarf," " impoverished," " starv- 

 ed," or " depauperated " specimens. Such also not unfrequently appear in books ranked 

 as varieties technically. On the same principle, moreover, in these tribes suffering 

 variation so freely, " gigantic" specimens (elevated occasionally to the rank of varie- 

 ties) are met with, dependent for their extravagant luxuriance on some peculiarly ap- 

 propriate site, or peculiarly adapted soil or medium. 



Artesiak Wells. — At present more than thirty Artesian wells are in progress 

 in the departments of France. That at the Abbatoir, near the Barriere de Crenelle, 

 becomes every day more interesting. The boring has already reached the depth of 

 1360 feet. This well was commenced on the 30th December 1833, and during the 

 1200 days which have elapsed since then, the works have been directed by M. Mulot, 

 jun., and have not been discontinued for a single day. From this it appears that the 

 average progress has been upwards of thirteen inches per diem. It appeare that the 

 administration are about to make an engagement with M. Mulot to bore to the depth 

 of 1800 feet, if water be not previously met with. A well begun at Dresden had 

 obtained in October last an abundant supply of water at the depth of 840 feet. This 

 source, having a temperature of 68^ Fdhr., furnishes a supply of 14 gallons of good 

 water per second. They penetrated through 62 feet of sand and gravel; 810 feet of 

 marl and chalk ; 43 feet of pure marl ; and 22 feet of greyish freestone. Admitting 

 the above temperature to be that of the strata at this depth, and comparing it with the 

 mean temperature at the surface of the earth at Dresden [48° Fahr.J, we find auni. 

 form increase of temperature of 1.20** Cels. for every 100 feet, or. 1** for every 78 

 feet of depth ; but this increase being greater than that actually observed in boring, 

 we must conclude that the water of this well comes from a greater depth. — UEcho 

 du Monde Savant. 



Edinburgh: Published for the Proprietor, at the Office, No. 13, Hill Street. 

 London: Sjjith, Elder, and Co., 65, Cornhill. Glasgow^ and the West of 

 Scotland: John Smith and Son; and John Macleod. Dublin: Georgb 

 Young. Paris : J. B. Balliere, Ruede I'Ecole de Medecine, No. 13 bis. 



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