ELEMENTARY STRUCTURE. 



25 



the Lime, &c., we find a spiral fibre or fibres developed in addi- 

 tion to the pits, which appearance also must be considered as 

 another proof of the common origin of fibres and pits. 



4. Contents or Cexxs. — Under this head are included nearly 

 all the substances which are formed in the plant, or which ha e 

 been absorbed by it from the soil. We only propose at present 

 to treat of those contents of cells which are more commonly 

 found, and which hare an especial importance at this stage of 

 our inquiry. The more particular description of many of them 

 will be given under the head of Physiology, or, when treating 

 of the plants which yield them, in Systematic Botany. The de- 

 tailed account of others, again, belongs to Chemistry, and the 

 applications of Botany to Medicine, the Arts, Domestic Economy, 

 and Manufactures. By some authors the term endochrom e { _fia. 

 27, b ,b.) is used to_in dJ£ate. 4he^whg le. .coMeatS of thp re]]; 

 it Ts cMellyso emplov"e drinTes cribing the Algse. We shall first 

 describe those contents which are more . especially present in 

 very young cells ; these are the Protoplasm, F rimordia l Utricle, 

 and 2<udeus. ' 



Frotoplasm. — This substance, which is abundant in all young 

 cells, is a white or yellowish opaque viscid fiuid, either perfectly 

 smooth, or of a more or less granular nature. I t^may be detected 

 b^the application of sugar and sulphuric acid, w hen it assyinps, 

 noore o r less ra pi'cr[y,"a pink or rose colour . Iodine colours it 

 jellow of ^own t It is_aiso coloured by carmine and some other 

 al-kalme col ouring mattex s, w HTIeTEecell-wail, under such circumT 

 gtaEce sTTslSot coloured at all , o r only very slightly tinted . It is 

 cofTguIated by acids and alcohoT It contains nitrogen * as an 

 essential iflgredieiit, in addition to the three elements- — carbon, 

 oxygyii;~and hydrogen, of which we have seen the primary cell- 

 membrane is alone composed. The protoplasm is called by some 



Fig. 50. 



German writers ' schleim,' a nd in some 

 English wo rks ' mucus,'"0r ' mucilage .' 

 It is the" ^rniinarmatter of Beale, who 

 r egardslt as composed of minute sphe^ 

 rfcai particles, an d these, again, "of 

 smaller J355 eriiTes. 



Primordial, Utricle. — When a cell 

 containing protoplasm is placed in 

 water, or allowed to remain for some 

 time in alcohol, or is exposed to the 

 action of iodine, the contents separate 

 from the wall (Jig. 50), and are then 

 seen to be bounded by a more or less 

 defined portion of protoplasm, having 

 the appearance of a membrane, and which by its contraction has 

 removed all the other contents of the cell from the wall. This mem- 

 brane is readily distinguished from the cell- wall formed of celMose 



Fig. 50. Cell of tbe leaf of 

 Jungermmmia Taylori. 

 After ilolil. 



