440 NATURAL HISTORY OF PLAINTS. 



lJeile>ruars or llloss-<^^alls, several Brambles, Agrimonies, and Al- 

 cheinils, Drupwort, and several other species of Sjjiraa. 



Another product of the bark of RosacecB is gum, whose forma- 

 tion results from a morbid condition' in most of our wild or cultivated 

 Pnnirtp, especially the common Plum, the Apricot, and the two com- 

 mon Cherries. In many of these trees as they grow old it exudes 

 spontaneously from the stem and boughs. Tliis gum (known in 

 France as yoiinnc de France or nostras), imperfectly soluble in water, in 

 which it swells out considerably, is no longer employed in medicine, 

 and is only used in preparing felt for the hatter. The best known is 

 that found in large quantities in the superficial integument of Quince 

 pips,-" which is much used as a demulcent in medicine, and in arts and 

 domestic economy for its glutinous properties. Next to gums come 

 the forms of mucilage so abundantly produced in several Rosacea. 

 A])plc and Pear pips may also supply a small quantity of this muci- 

 lai^inous substance ; but it is especially abundant in the barks of the 

 dill'erent soap-Quillais, especially QidUaja Sajjonaria,^ Smepnaderinos,* 

 and brasiliensisJ' It is probably the bark of one of thiese, perhaps the 

 tirst, which is often sold in Paris under the name of ecorce de Panama 

 (Panama Bark). Powdered and mixed with water this substance 

 makes it froth like soap-suds, and gives it the property of removing 

 grease from woollen and silk stuffs." 



' See A. TiifccUL, Malad. de la Gomme chez for gum-channels are folds in the cell-memtranes. 



lex Cerisier.1, les Pntniers, les Abricotiers, les In the Apricot these cells are often dilated, and 



Amandiers (Compl. Rend, de I'Acad. des Sc.,\\. form necklaces, between the heads of which are 



624) ; Product, de la Gomme chez le Cerisier, septa, which may be more or less completely 



U Pnmier, VAmandier, VAhricotier, et le Pecker absorbed. These cavities and those of the woody 



(I'lnslit., XXX. n. 1490, 211). The gum was fibres themselves in certain Pruned: may contain 



formerly believed to be secreted by the cells of not only gum but also cerasome, a substance which 



the inner bark of these plants. It was sup- is neither gum nor cellulose, and is not acted 



P<kmh1 to be deposited in the outer cellular tissue, upon by iodine or sulphuric acid even after boil- 



nnd when the bark is finally torn open, to flow ing in potash. In the cavities of the sap wood 



out. KuETZiNO announced in 1851 that the we also find around the true gum another sub- 



c»;Uulo8e membranes might be transformed into stance, which does not swell up in water, and 



tiuni. In 1857 Kahsten affirmed that all gums turns bright pink in contact with iodine and 



and muciliiges were the result of some such sulphuric acid. 



chnnKc. Wioaxd, in the first part of his ^ Ct/donia vulgaris Pees. (p. 395, figs. 463- 



mcmoir, I'eber die Beorganis. der Pflanzenz. 465). The fruit is the Cydonia or Cotonea of 



(Pnngth. Jahrb., iii. 115), studied the transfor- pharmacopoeias and the KvSuvia of Hippocrates, 



mation of the tissues of the wood and bark of ^ MoL., Chit., ed. 2, 298.— Q. ? MolincB DC. 



Rniarra, TittcrL thinks this gum is a purely Prodr., ii. 547, n. 2. 



pntholopml product extravasated into equally " DC, loc. cit., n. l.— Q. Saponaria PoiE. 



morbid ravit.es. Under the influence of a too Diet, vi. 33 (nee Moi.., ex DC). 



lar^o iiupply of nourishment the young cells of » Mart., Syst. Mat. Med. Bras., 127.— Fan 



tlio gi-nemtive layer may be absorbed; the tenellea bras'ilietisis A. S. K. & TVL., Ann. Sc 



Vi^-^eU may bo similarly destroyed, and so form Nat., ser. 2, xvii. 141, t 7 



i-aviti«i, on the wnlU of which appears the gum, « This property seems due to a peculiar pun. 



«hich thence Rprcnd. int.. the neighbouring an- gent substance, which BoUTRON & Henry 



»r...tuo»itits. The i.tri»> which have been taken (Joum. de Pharm., xiv. 247 ; xix. 4) have found 



