CELLULAR TISSUE. 



[ 125 ] 



CEMENTS. 



quently splitting to form the fibrils, does not 

 appear to have been determined. See Fi- 

 brous TISSUES. 



BiBL. Kd\\iker,Geweb€lehre,i^'C.; Paget, 

 Report, Sfc, Brit, and For. Med. Rev. 1842, 

 xiv.; Mulder (and Bonders), Physiol. Chem.; 

 Todd and Bowman, Phys. Anat.Sfc; Drum- 

 mond, Ed. Monthly Journal, 1852 (these 

 contributions form models of the manner in 

 which the microscope and chemistry should 

 go hand in hand ; but the power used, 250 

 diameters, is too low ). 



CELLULAR TISSUE, OF Plants. See 

 Tissues, Vegetable. 



CELLULARIA, Lamk.— A genus of Po- 

 lypes, belonging to the order Bryozoa (Po- 

 Ivzoa). 



Char. Poh'pidom calcareous or membrano- 

 calcareous, confervoid, divided dichoto- 

 mously, the divisions narrow, composed of 

 two or three alternating series of oblong 

 contiguous cells on a single plane, the aper- 

 tures lateral, oblique, and facing one way. 

 Polypes ascidian, with usually 14 tentacles ; 

 no gizzard. 



Eight British species. 



Two of the species are common on the 

 British coast, attached to other zoophytes, 

 the roots of fuci, &c. 



C. rejitans (PL 33. fig. 5). Creeping, di- 

 chotomous ; cells with an oblique, superior, 

 subterminal, oval aperture, armed w ith short 

 spines at the top. 



C scruposa. Creeping, dichotomous; cells 

 alternate, with a plain, superior, svibterminal, 

 oval aperture, and a projecting angle on the 

 outer side of each. 



BiBL. Johnston,Bn^.Zoop^.l847,i.; Reid, 

 Ann. Nat. Hist. xvi. p. 385 ; Van Beneden, 

 Nouv. Mem. de VAcad d. Brux. 1845. xviii. 



CELLULOSE. — The proximate principle 

 of which the permanent cell-membranes of 

 plants are always composed, and occasionally 

 those of some structures of certain animals, 

 as the mantle of the Tunicata. (See Tuni- 

 CATA.) Its physical characters differ very 

 much in different cases ; sometimes it is ex- 

 ceedingly soft, acquires a blue colour with 

 iodine, and dissolves in sulphuric acid (amy- 

 loid?). Usually it is more dense, and does not 

 become coloured blue with iodine until after 

 treatment with sulphuric acid, when it be- 

 comes more or less bright blue (the ordinary 

 test for cellulose). Occasionally this reaction 

 gives a pm-plish colour. In old, infiltrated, 

 or greatly consolidated cellulose structure, 

 this test gives only a yellow-brown colour ; 

 but boiling in nitric acid (for woody tissues) 



or solution of potash (for epidermal tissues) 

 will generally bring the cellulose into a state 

 when, if wetted with tinct. of iodine, dried, 

 and then wetted with water, it turns blue. 

 Sulphuric acid is the most ready solvent of 

 cellulose ; solutions of potash and nitric acid 

 do not act so quickl}^, especially the latter. 

 Sulphuric acid always swells it before dis- 

 solving. 



BiBL. See Amyloid, Cell-mem- 

 branes, and Chemical Reagents. For 

 occurrence of cellulose in animal tissues, — 

 Schacht, Mull.Archiv, 1851, Microsc. Journ. 

 1852, pp. 34 and 106 ; Huxley, Microsc. 

 Journ. 1852, p. 22; Schmidt, transl. in Tay- 

 lor's Scientific Memoirs, 5. p. 1; Kolliker 

 and Lowig, Ann. des Sc. nat. 3 ser. Zoologie, 

 1846. p. 193; Virchow, Comptes Rendus, 

 1853 {Ann. Nat. Hist. 2 ser. xii. p. 482) ; 

 Busk, Microsc. Journal, 1854. 



CEMENTS.— These are used for closing 

 the cells in which microscopic objects are 

 placed for preservation, also for fastening 

 pieces of glass to each other, to form cells, 

 &c. Those, the method of making which 

 we have not described, can be procured at 

 any oil- shop. 



1. Asphalte varnish consists of a solution 

 of asphalte in boiling linseed-oil, or oil of 

 turpentine, or in a mixtm'e of the two. 



2. Black Japan consists of asphalte, gum 

 animi, amber, linseed-oil, and oil of turpentine. 



3. Brunsivick black consists of asphalte, 

 drying linseed-oil, and oil of turpentine. 



4. Canada Balsam; a. alone; b. digested 

 at a gentle heat with sufficient aether to ren- 

 der it slightly more fluid. 



5. Electrical cement — a. is made by melt- 

 ing together 5 parts of rosin, 1 part of bees'- 

 w^ax, and 1 of red ochre, b. The addition of 

 2 parts of Canada balsam renders this ce- 

 ment much more strongly adhesive to glass. 



6. Gold-size may be prepared by boiling 

 25 parts of linseed-oil for three hours with 

 I part of red lead and i of a part of umber ; 

 then pour off. Successive portions of a 

 finely powdered mixture of equal parts of 

 white lead and yellow ochre are then added 

 to the oil, being w ell rubbed and mixed with 

 it, until a tolerably thick liquid is formed; 

 this must be once more thoroughly boiled. 

 It is also sold. 



7- Gutta-percha cement is made by adding 

 15 parts of oil of tm'pentine to 1 part of 

 finely cut-up gutta-percha, and dissolving 

 by the aid of a continued heat and stirring. 

 The solution is then strained through a cloth. 

 In the strained solution 1 part of shell-lac is 



