] 



GLADIOLUS. 



GLAND. 



general thawing of all the part* exposed to the direct rays of the nun, 

 to the warm atmosphere, and to the heated soil at the edge* of the 

 tends greatly to diminish the quantity of ice an effect 

 by the mechanical action of the torrent* which Una thawing 

 L But all these causes, powerful as they are, would be insuf- 

 ficient to prevent a constant though gradual increase of the ice, were 

 it not for the advance of the glaciers into the warm atmosphere of 

 the lower valley*. The greater the increase of the preceding winter 

 the greater the pressure from above, and the lower the glacier slips 

 into the thawing region. The farther it slips the greater space is left 

 behind to be filled up, and consequently the greater time must elapse 

 before the mass can again be urged forward. During this time the 

 lower extremity, subjected to the heat of two or three summers, 

 recede* as much as or more than it had before advanced ; and thus an 

 admirable compensation is established, by which the cultivated lands 

 of the lower valleys are secured against the unlimited encroachments 

 of the glaciers. 



The number and extent of the Alpine glaciers is very considerable, i 

 From Mont Blanc to the borders of the Tyrol there are reckoned . 

 about 400 glaciers, of which a very few are only 3 miles in length ; 

 the greater number range from 10 to 15 miles long, and from a mile 

 to 2J miles broad. The thickness of some of the glaciers is also very 

 considerable, being from 100 to 600 feet 



It is calculated that the glaciers of the Tyrol, Switzerland, Pied- 

 mont, and Savoy form together a superficial extent of 1484 square 

 miles. Such are the great reservoirs whence some of the principal 

 rivers of Europe draw their inexhaustible supplies. It is observable 

 that there are but fw glaciers in the direction of east and west. 



The above account refers chiefly to the glaciers of the Alps ; but 

 as all glaciers, wherever they may be, have the same origin, it is 

 presumable they are also subjected to like influences, and present 

 similar phenomena. 



The Pyrenean chain, as also the Sierra Nevada, have glaciers, 

 though they are almost all on the northern slopes, there being none 

 on the southern declivities, except in such places as are sheltered from 

 the sun and south wind by other and morn advanced mountains. In 

 the mountains of Norway there are several glaciers. Spitzbergen has 

 its eminences covered with snow and surrounded by glaciers. 



In let-land the glaciers are both numerous and extensive ; they 

 generally hang on the rapid slopes of the mountains, and sometimes 

 wholly encase them. These ice-clad elevations are termed Jokiils, 

 the principal of which is that named Klofa Jokul, in the eastern 

 quarter of the island, and which, according to Henderson, forms, with 

 little or no interruption, a vast chain of ice and snow mountains not 

 lew than 3000 miles square. Another, called Blafell's Jokul, extends 

 from near Tindafiall 100 miles across the island in a westerly 

 and northerly direction, and near the Lake Uvitarvatn presents the 

 most magnificent glaciers. There are numerous other glaciers ; many 

 of them, besides the usual phenomena, exhibiting marks of the extra- 

 ordinary convulsions occasioned by volcanic action and the emission 

 of hot water from the sides of the mountains. 



Greenland, as far as is known, contains innumerable glaciers, many 

 of great thickness ; and the inhabitants of both the cast and west 

 coast are persuaded of their continual increase. It is remarkable that 

 although (Jraah, in his account of Greenland, describes the glaciers as 

 formed in the same manner with those of the Alps, yet he and all 

 travellers notice the beautiful transparency and consequent compact- 

 ness of the northern glaciers, and of the icebergs which have been 

 detached from them ; a circumstance which seems to denote some 

 peculiar modification of the process of their' formation. 



Along the south-west coast of South America there are extensive 

 glaciers, as also in the Strait of Uagolhoens, and in Tierra del 

 Fuego. 



In the Himalayas glaciers have been observed, and all the phenomena 

 presented in Em-ope have also been found there. 



(Saussure, Voyage* dam let Alpr; Mallet, in Traru. of the />W 

 Owl Society ; Forbes, in Jamttun'i Journal, and Tour in the Al/*; 

 Hopkins, in Cambridge Trant. and Phil. Magazine ; Lyell, 



GLADIOLUS, Corn-Flag (from 'gladius,' a sword, referring to the 

 shape of the leaves), a genus of Plants belonging to the natural order 

 Jridacetr. It bos a tubular 2-lippcd corolla ; segments undulate and 

 unequal; stigma trifid ; seeds with on arillus; root a coated bulb; 

 leaves ensiform, sheathing. The species in the gardens are bulbous, 

 and are chiefly brought from the Cape of Good Hope. 



(/'. ttgetvm has about 10 flowers in two rows. The upper division 

 of the corolla is divaricate, the lower segment nearly equal and lanceo- 

 late ; anthers longer than the filaments ; capsules with 3 furrows. It 

 ha* been supposed to be an aphrodisiac, a reputation obtained from 

 iU acrid qualities, which are however common to the whole of the 

 order. The Hottentots eat the tubers or corn of several species of 

 this genus, the starch they contain rendering them nutritious. 



<!. irijihyllui has about 3 flowers in one row ; the anthers much 

 shorter than the filnuicnt*. It is found in the mountains of Carrara. 



O. paliulnt has 8 or 4 flowers, secund ; the tube twice as long as 

 the ated-veanel ; the claw of the middle division curved and remote ; 

 the lobes of the stigma papilloso-ciliate almost from the base ; anthers 

 shorter than the filaments; auricles at the base obtuse, parallel; 



capsules oblong, obovate, rounded at the top, marked with six equal 

 furrows. It is found in Germany. 



II. eoinmunit has secund flowers ; the filaments half as long again as 

 the anthers ; auricles at the base obtuse and parallel ; the tube half 

 as long again as the germen ; lobes of the stigma gradually broader 

 upwards, papilloso-ciliatc almost from the base; capsules S-. 

 obovate, impressed at the top ; the seeds broadly winged. It is found 

 near Stettin and Frank furt-on-Oder. 



n, niijrimt has secund flowers ; the tube three times as long as the 

 germen; division of stigma linear from the base to the middle, nn<l 

 with a smooth margin suddenly enlarged at the top with u papilloso- 

 ciliate margin ; the capsules obovate, 3-edged. A native nf lllyrix 



(/. \mbricaltu has secund approximate flowers ; the tube nearly 

 three times as long as the germen ; the division of stigma gradually 

 broader upwards, papilloso-ciliate almost from the base ; the capsules 

 with 3 rounded angles. Found in Bohemia and Silesia. 



H. hifeiltu has a lax spike; flowers 4 to 14, obliquely alternate ; 

 division of corolla alternately pink and purple, uppennost very broad, 

 covering the 2 lateral ones, the 3 lower unequal ; anthers about as 

 long as the filaments; seeds globose, prolonged downwards. It is a 

 native of Sicily. 



'/. llf/zantinut has numerous flowers in two rows ; the upper seg- 

 ment of the corolla covered by the lateral ones ; the lower division 

 lanceolate, the middle largest ; the anther* longer than the filaments ; 

 seeds winged ; leaves long, enaiform, and linear. Found in Sicily. 



GLAND, a term applied to cells and collections of cells in the aniin.il 

 body, which have the power of absorbing or separating the various 

 substances which pass into or are separated from the circulating 

 fluid. In one sense all the cells of the animal act as glands, for they 

 separate from the blood the peculiar substances of which they are 

 composed. The term gland however is only strictly applied to special 

 forms of tissue which separate peculiar matters. " A true gland," 

 says Dr. Carpenter, "may be said to consist of a closely pocket! col- 

 lection of follicles, all of which open into a common channel, by 

 which the product of the glandular action is collected and delivered. 

 The follicles contain the secreting cells in their cavities, whil-t tin -ir 

 exterior is in contact with a network of bloodvessels from which the 

 cells draw the materials of their growth and development" 



In a wider sense however the term gland has been applied to those 

 parts of the body which are engaged in absorbing the food or carrying 

 to the blood the materials of used-up tissues. [AMOUNT SYSTEM ; 

 ABSORPTION], In all casea the cell is an active agent whether of absorp- 

 tion or Reparation. The agency of the cell in absorption is seen in 

 the way in which the chyle is taken from the intestines and carried 

 into the lacteaK 



Professor Goodsir has recently shown that there is a continual 

 development of cells at the extremity of each villus in the small 

 intestine, and that these cells arc the agents by which the secretion 

 of the nutritious fluid is accomplished, and by which it undergoes its 

 first preparation for the purposes it is subsequently to fulfil. The 

 nature of this process we give in Professor Goodsir's own words, 

 omitting those portions which do not bear specially on the point 



"As the chyle begins to pass along the small intestine, an increased 

 quantity of blood circulates in the capillaries of the gut In consen 

 of this increased flow of blood, or from some other cause with which I 

 am not yet acquainted, the internal surface of the gut throws off its 

 epithelium, which is intermixed with the chyme in the cavity of the 

 gut. The cast-off epithelium is of two kinds, that which covers the 

 villi, and which, from the duty it performs, may be named prot 

 epithelium; and that which lines the follicles, and is endowed with 

 secreting functions. The same action then, which in removing the 

 protective epithelia from the villi prepares the latter for their peculiar 

 function of absorption, throws out the secreting epithelia from the 

 follicles, and thus conduces towards the performance of the function 

 of these follicles. The villi, being now turgid with blood, ei 

 and naked, are covered or coated by the whitish-gray matter already 

 described. This matter consists of chyme, of cast-off epithelia of the 

 villi, and of the secreting epithelia of the follicles. The function of 

 the villi now commences. The minute vesicles which are interspersed 

 among the terminal loops of the lactcals of the villus, increase i : 

 by drawing materials from the blood through the coats of the capil- 

 lary vessels, which ramify at this spot in great abundance. While 

 this increase in their capacity is in progress, the growing vesicles are 

 continually exerting their absorbing function, and draw into their 

 cavities that portion of the chyme in the gut necessary to supply 

 materials for the chyle. When the vesicles respectively attain in 

 succession their specific size, they burst or dissolve, their coi 

 being cast into the texture of the villus, an in the case of any other 

 species of interstitial cell. The deliris, and the contents of the dis- 

 solved chyle-cells, as well as the other matters which have already 

 subserved the nutrition of the villus, pass into the looped network of 

 lactcals, which, like other lymphatics, are continually employed in 

 this peculiar function. As long as the cavity of the gut contains 

 chyme, the vesicles of the terminal extremity of the villi continue to 

 develop, to absorb chyle, and to burst, and their remains and contents 

 to be removed along the lactcals. When the gut contains no more 

 chyme, the flow of blood to the mucous membrane diminishes, 

 I elopmcnt of new vesicles censes, the lacleals empty themselves, 



