819 



SALIFEROUS SYSTEM. 



SAL1X. 



650 



and on the banks of salt rivers in Great Britain. It is known by its 

 herbaceous stem, compressed and notched articulations, somewhat 

 thickened upwards, and cylindrical spikes slightly tapering at the 

 extremities. This and many other species belonging to the genus, and 

 to the other genera of the same natural family, yield a great quantity 

 of soda, for the purpose of obtaining which they are collected on the 

 coasts of the South of Europe and the North of Africa. This species 

 is often eaten as a salad or pickle under the name of Samphire, but is 

 a different plant from the true Sampbire. [CRITHMUJL] 



S. rculicans has a creeping stem, and is considered by some botanists 

 a variety of the last. 



N. fi-'j,ticO!a, Shrubby-Jointed Glasswort, is a doubtful native of 

 Great Britain, but grows largely iu the south of Europe and in North 

 America, and is used for the fame purposes as the above. 



.SALIFEROUS SYSTEM. [RED-SANDSTONE.] 



SALISBU*RIA, a genus of Plants belonging to the natural order 

 Taxacece, named in honour of R. A. Salisbury, a modern botanist of 

 distinction. The tree, which is the only one of the genu, has long 

 been known by the Japanese name Gingko. The genus is characte- 

 rised by having moncecious flowers. The male flowers disposed in a 

 filiform naked catkin, without calyx or corolla; stamens numerous ; the 

 anthers composed of 2 cells, which are pendulous, and united only 

 at the apex. Female flowers solitary and terminal ; calyx 4-fid, or 

 rather a cup-shaped disc, from the thickened apex of the peduncle, 

 surrounds the base of the solitary ovule ; fruit forming a drupe, which 

 has its base supported by a fleshy cup, with a juicy white pulp ; seed 

 nut-like, with an osseous shell; kernel white; embryo axillary, 

 dicotyledonous, radicle above. 



S. adiantifolia, the Gingko, grows naturally in Japan, is much culti- 

 vated in China, and is found iu many gardens in Europe. Fine old 

 specimens may be seen at Kew and in the Apothecaries' Garden at 

 Chelsea. In congenial climates it attains the size of the walnut. It is 

 remarkable for the form of its leaves, which are wedge- or fan-shaped, 

 deeply cut in the centre or bilobed, and finely striated with veins, 

 having some resemblance to the leaves of some species of Adiantum, 

 whence it is commonly called Maiden-Hair Tree in this country. The 

 pulp of the fruit is austere-tasted, but the kernel is sweet, with some 

 degree of bitterness when raw, but agreeable as a dessert when roasted 

 like chestnuts. They are much eaten in China. Dr. Abel says he 

 saw the fruit exposed in the markets iu China, but could not find out 

 to what purpose it was applied. [CoxiFEit.K.] 



SALI'VA, SALIVARY GLANDS. The principal glands by which 

 the saliva is secreted are six in number, three being situated on each 

 ide of the face, namely, the parotid, the submaxillary, and the sub- 

 lingual glands. Of these the parotid is considerably the largest, and 

 has been already described. [PAROTID GLAND.] The submaxillary 

 tl.-md, which is next in size, has its principal mass situated immedi- 

 ately behind and beneath the middle of the base of the lower jaw, 

 below the mylohyoideus muscle, round the posterior edge of which a 

 portion of it is continued, and leads to the aubinaxillary or Whartonian 

 duct. The latter passes forwards and inwards, and opens on the sur- 

 face of the mucous membrane of the mouth, just by the side of the 

 fnenum of the tongue. The sublingual gland is the smallest of the 

 chief salivary glands; it is situated close by the duct of the mibmaxil- 

 lary, into which several of its ducts open ; others have their orifices 

 on the surface of the mucous membrane of the mouth, by the side of 

 the froonum lingua:, and further outwards. Besides these larger glands 

 there are a vast number more which secrete saliva, and which are 

 situated in the substance of the lips and cheeks immediately beneath 

 their mucous membrane, on whose surface their ducU open. Indeed 

 the whole interior of the lips and checks is lined by a congeries of 

 small glands, which in structure closely resemble the salivary, and 

 probably do not differ from them in function. 



The saliva as it exists in the mouth is not only the produce of these 

 glands, but also of the buccal surface of the mouth. When not mixed 

 with air it is a transparent, rather viscid fluid, which is usually weakly 

 alkaline, but during the mastication of food it is often slightly acid. 

 It is composed of a great proportion of water, mixed with portions of 

 the epithelium of the mucous membrane lining the mouth, and holding 

 in solution about seven parts in one thousand of albumen, salivine (a 

 principle almost peculiar to itself), and other animal matters, together 

 with the saline substances found in the blood, and a very minute 

 quantity of sulpho-cyanide of potassium. 



One of the purposes served by the saliva seems to be the softening 

 of the food, with which it is intimately mixed in mastication. Glands 

 for its formation exist in all classes of animals from the insects 

 upwards (with the exception of fish), and even in many that are lower 

 in the animal kingdom than the insects. The saliva appears also to 

 exert a chemical influence on the starchy parts of food, converting 

 them into sugar. This power is not possessed by the secretion from 

 the glands alone, but resides in the common saliva of the mouth. 



The quantity of saliva secreted when the mouth is at rest is only 

 sufficient to keep its internal membrane moist and slippery. When 

 however the jaws are actively moved, and especially during feeding, 

 or even at the thought of a meal or of certain kinds of palatable food, 

 the quantity is greatly increased. During the twenty-four hours it is 

 probable that from sixty to ninety grains of saliva are secretjd by one 

 parotid gland (Mitacherlich), and the quantity produced by all the 



salivary glands of an adult man together may therefore be estimated 

 at from four to five hundred grains. 



(Lehmann, Physiological Chsmittry, translated by Dr. Day for 

 Cavendish Society.) 



SALIX (Latin, 'salix,' a willow), the name of a genus of Plants, 

 which, in conjunction with Popuhis, constitutes the natural order 

 Salicacece. Iu many respects tliis is one of the mast important genera 

 of plants : the rapidity of their growth, the toughness and lightness 

 of their wood, and their uses in medicine and the arts, have caused 

 them to be extensively cultivated. But although largely cultivated 

 and well known in most parts of the world, the botanical arrangement 

 of these plants presents considerable difficulties, and few genera have 

 had more time and labour spent upon them than Salt.*:; and up to tho 

 present time the most able botanists differ as to the real nature of 

 many species or varieties. 



The genus Salix is known by possessing dicecious flowers ; catkins 

 many-flowered, imbricated, composed of a single-flowered flexible 

 bract. The barren flowers have a small lateral abrupt gland, some- 

 times double ; filaments 1, 2, 3, 5, or more, longer than the bract, and 

 in some partly combined; 2-lobed anthers, opening longitudinally. 

 The fertile flowers with a nectariferous gland; ovate, 1 -celled, many- 

 seeded ovary ; permanent terminal style, with two stigmas, which are 

 notched and obtuse or cloven acute, aud spreading ; ovate capsule 

 composed of two revolute concave valves and one cell ; numerous 

 miunte oval seeds, tufted with soft, simple, upright hairs. The willows 

 are chiefly natives of the colder parts of the temperate regions of the 

 northern hemisphere. S.herbacca, and & arcliea are found nearer the 

 pole than any other woody plants. S. Babylonica is a native of Chiua, 

 Japan, Armenia, and the north of Africa. Of all the species enumer- 

 ated, only 17 are extra-European. 



The Willow was known to the Greeks and Romans ; in fact little 

 has been added to our knowledge of the properties and uses of these 

 plants since their time. On account of the flexible nature of their 

 shoots and the toughness of their woody fire, they have always been 

 used as materials for making baskets, hoops, crates, &c., aud for these 

 purposes great quantities are cultivated iu this aud other countries. 

 The bark is made use of in the north of Europe for the purpose of 

 forming mats in the same manner as the bark of the common linden- 

 tree. In Tartary the woody fibre is macerated and separated, and 

 thm spun into threads, from which cloth is woven. Willows are much 

 used in the manufacture of charcoal ; and it has betii proved that 

 Willow Charcoal is superior to that procured from the wood of most 

 other trees for tho preparation of gunpowder. The bark of nil the 

 willows contains the tanning principle, and, according to Sir If. 

 Davy, some of the species, especially <S. Russelliana, S. alba, and S. pur- 

 purea, contain as much as tho oak itself. From the bark of some is 

 obtained a vegetable principle called Saliciu, which acts upon the 

 system in the same manner as quiuiue, and is used for the same 

 purposes. 



In order that the species of this genus may be studied successfully, 



a uumber of points require consideration, and it is only lately that an 



i approach has been made to accuracy in their investigation. The flowers 



of the Salix are subject to many anomalies which have been productive 



of not a little difficulty, and have sometimes led to the supposition 



that this genus was an exception to the ordinary laws of vegetable 



development. The principal anomalies that are found are 1, male 



I and female flowers occurring in the same catkin ; 2, stamens apparently 



, changed into pistils ; 3, stamens accompanied by an imperfect pistil ; 



4, entire union of the filaments of the stamen. In the study and 



description of the species, it is of importance that the tendrncy to 



these anomalies should not be overlooked. Another difficulty iu the 



way of the study of this genus is the occurrence of hybrids. 



There are at present described nearly 300 species of Salix ; of all 

 which we shall not here give a description, but arrange the more com- 

 mon species under the heads Sallows, Osiers, and Willows. These 

 terms are often applied to any of the species, but some have more 

 i frequently one of the designations than the other. 



SALLOWS. 



These are trees or low shrubs belonging mostly to Borrcr's group 

 Cincrcte, and are characterised by downy branches, and mostly obovate, 

 gray, hoary, toothed, more or less wrinkled, and stipuled leaves, very 

 veiny beneath. Ovaries sericeo-tomentose. 



S. cincrea, Gray Sallow. Stem erect ; lower leaves entire, upper 

 serrated, obovate-lanceolate, glaucous, downy, and reticulated with veins 

 beneath ; stipules half-heart shaped, serrated ; ovary silky, style short, 

 stigmas mostly entire. It attains a height of 20 or 30 feet, and is 

 abundant in England on banks of rivers and in moist woods. 



S. ai/uatica, Water-Sallow. Stem and branches erect ; leaves slightly 

 sefrated obovate-elliptical, minutely downy, and rather glaucous be- 

 neath ; stipules rounded, toothed ; ovary silky, stalked, stigmas nearly 

 sessile. This is also a British species, and one which Koch has made a 

 variety of .S'. cincrea. The Olive-Leaved Sallow (S. oleifolia) is also 

 referred by Koch to .S'. cincrea. 



H. awita, Round-Eared Sallow. Branches trailing ; leaves obovate, 

 somewhat serrate, convex, obtuse with a small hooked point, hairy, and 

 reticulated with veins on both sides : stipules roundish, couvex, 

 toothed ; ovary silky, stalked, stigmas nearly sessile. 



