CONTENTS OF CELLS. 



11 



lai^ cell (fig. 39) — filling -what some have supposed to be the base 

 of an undeTeloped hair. The crystals are of dififerent 

 sixes and forms. OceasionaUy, a single large crystal 

 nearly fi lls a cell, as in the outer scales of the onion, 

 but in general there are numerous crystals united to- 

 gether. Sometimes the crystals radiate from a conmion 

 {mint (figs. 40, 41), and form a conglomerate mass ; at 

 other times they lie parallel, and have the appearance of 

 bundles of fine needles (figs. 37, 38). To the latter, the 

 name of Bt^MtUs Qafi;, a needle), or acicular crystals 

 (aais, a needle), was originally given. It has been said 

 that th^e crystals exist also in the i;itercellular spaces ; 

 but this seems to depend on the mode in which the section of the plant 

 is made, for when raphidian cells (fig. 42, r r r r) are situated dose to 

 a lacuna, the crystals may easily be pushed into it accidentally by the 

 knife. Baphides consist principally of phosphate and oxalate of lime. 

 They abound in some plants, especially Cacti, and they are common in 

 Squill, and in the officinal Turkey Rhubarb, the latter of which owes 

 its grittiness to their presence. One hundred grains of rhubarb root 



Kg. S 



Fig, SS. 



Kg. 39. 



Kg. M. 



Kg.41- 



contain about 30 or 40 grains of oxalate of lime crystals. Acicular 

 crystals may be eaaly seen by making a section of any Liliaceons 

 plant, as the hyacinth, and spreading the thick mucilaginous matter 

 of the cells on the field of the microscope. Radiating raphides are 

 seen in the sepals of Gleranium robertiannm and luddum ; the crystals, 

 consisting of oxalate of lime, fill the whole of the cells in the middle 

 of the sepal, their size varying from wsif to rim of an inch. Quekett 

 found them in all the species of Pelargonium and Monsonia that he 

 esunined, and he thinks that they are as general as the beautiful 

 markings in the cutide of the petals of these plants. Clustered crystals 

 have been detected in Malvaceous plants, under the cutidp of the 



Fig. 37. CeUnlai tissue oT Arom macnlatum. c, OeDs ccmtainiDg chloroph^ r r, 

 Bapludiaii cells. Kg. SS. OeDs of Anunnwailatojn. Ctosteisaf lapUdes ijtalaige 



OT»l ceU surrotmded by smaUer cells. Kg. S9. Celhilar tissne from leaf of Hens elastica. 

 c, A lai«e celL r, CystoUth, an agglomeration of ciystals (sphffirapliides) sospended in a 

 sac 1(y a talie, t «, Ctricles filled mthgiains of clilorophyll. Fig. 40. Cells of Beet with 

 conglomerate ladiating ciystals, o. i. Separate cijstals of different fonns. Kg. il. Con- 

 ^omejtate crystals of oxalate of lime from Khubarb. 



