LIGNINE. 



[ 395 ] 



LIME, 



Some of these tissues also contain cartilage- 

 cells. 



Fig. 407. 





Maornified 350 diameters # 



Cartilage-cells from the membranous ligament sur- 

 rounding the poplitseus muscle, fl, cell with one nucleus; 

 b, cell with two nuclei ; c, cell containing one, d, two 

 secondary cells, the contents of both of which are more 

 consistent. 



The intervertebral ligaments consist of 

 fibro-cartilage, siuTountled by osseous tissue; 

 the centre is soft and containing concentric 

 cartilage corpuscles (fig. 106, p. 111). 



BiBL. KoUiker, Mikroskop. Anatomie, i. ; 

 Henle, Allgem. Anat. ; Donders, Mulder's 

 Physiol. Chem. 



LIGNINE. — A modified condition of cel- 

 lulose is obtained from old wood-cells, and 

 called by this name. It difi'ers in its re- 

 actions from pure cellulose, being coloured 

 yellow by sulphm-ic acid and iodine, but 

 after boiling in nitric acid and washing, 

 tincture of iodine and water give it a blue 

 colour. See Secondary Deposits. 



LIMBORIEiE.— A family of Angiocar- 

 pous or closed-fruited Lichens characterized 

 by rounded apothecia closed in by a carbo- 

 naceous special perithecium, finally bursting 

 in various ways, containing a somewhat 

 waxy nucleus, which grows hai'd. 



Synopsis of British Genera. 



I. Pyrenothea. Thallus crustaceous. 

 Apothecia round, carbonaceous, perforated 

 by a simple opening, protruding a globular 

 nucleus, which at length falls to pieces, 

 ultimately dehiscent, spread out, evacuated. 



II. Strigula. Parasitic on coriaceous 

 perennial leaves. Thallus mostly produced 

 beneath the cuticle. Perithecium sub-glo- 

 bose, collapsing at length, opening by an 

 irregular fissure or minute pore. Nucleus 

 at first gelatinous, at length hard, becoming 

 black and cracking when exposed. 



LIME, SALTS OF. 



Carbonate of lime. This substance is well 

 kno^^Ti as forming chalk, marble, &c., and as 

 occm-ring in hard animal stnictures, as bone, 

 shell, &c. It is not unfrequently met with 

 in the form of granules as a component of 

 various animal secretions, as the urine, &c. 

 In this liquid, it sometimes, but rarely also 

 occurs in little spheres or disks, consisting 



of groups of radiating needles. This we 

 first found to be the case in human urine 

 (PI. 9. fi.g. 8) ; but it was subsequently 

 detected in that of herbivorous animals, as 

 the cow and the horse (PI. 9. fig. 7)) in which 

 its occuiTcnce is common. It is also a com- 

 ponent of otolithes, in which it exists either 

 as granules or minute prisms, often with six 

 sides and trilateral summits. From river- 

 and spring-water it is usually de])Osited in 

 irregular and imperfect forms (PI. 9. fig. 6), 

 all of which consists of grouped needles. 

 Sometimes it assumes the rbombohedral 

 form, as in the shell of the oyster (PI. 37. 

 fig. 10), and frequently in chemical solutions. 

 When treated with a dilute acid, after having 

 been thoroughly washed in a watch-glass, it 

 is dissolved with effervescence from the 

 escape of carbonic acid gas. During the 

 solution it first becomes more transparent, 

 exhibiting the internal crj'stalhne structure, 

 and frequently a concentric or nuclear ap- 

 pearance, which finally disappears. When 

 derived from animal secretions, it leaves 

 undissolved an organic cast of the original, 

 provided the acid be not too strong, or its 

 action too long continued. If the number 

 and size of the minute bodies be relatively 

 very small in proportion to the amount 

 of water, on adding the acid, efferves- 

 cence will not occur, the water holding in 

 solution the carbonic acid evolved. The 

 presence of the lime may be tested in the 

 ordinary way, by the addition of oxalate of 

 ammonia, when the precipitate is insoluble 

 in acetic acid, or by adding dilute sulphuric 

 acid, when crystalline needles of the sulphate 

 of lime (PI. 6. fig. 16) are formed. 



The spheres or disks naturally occm'ring 

 in the m'ine, are closely imitated by those 

 formed in urine to which chloride of calcium 

 has been added, and which has been subse- 

 quently kept for some time. 



Lactate of lime may be obtained by 

 acting upon carbonate of lime with lactic 

 acid. It is soluble in water and alcohol. 

 The microscopic crystals consist of tufts of 

 delicate radiating needles (PI. 17. fig. 19). 



Oxalate of lime. This salt exists in solu- 

 tion in the contents of many vegetable cells 

 combined with a proteine-compound ; it is 

 also probably a normal constituent of the 

 human blood in small quantity, combined 

 and dissolved as in vegetables. 



In the cells of plants it is very frequently 

 deposited in a crystalhne form, constituting 

 Raphides. From human blood it has been 

 obtained in crystals by treating the alcoholic 



