538 



BOTANY AND PHARMACOGNOSY. 



varies even in the bark of the same thickness from the same 

 tree. When the exposure is such that the chloroplastids are 

 abundant in the cells of the bark, then the per cent, of the 

 1-mandelonitrile glucoside is higher, whereas when the exposure is 

 such that the cells do not take an active part in photosynthesis 

 the per cent, of the glucoside is lower. In the latter case the 



Fig. 235. Prunus serotina Ehrhart: A, longitudinal section of inner bark, showing 

 crystals of calcium oxalate (a), medullary ray cells (b and d) containing starch, leptome or 

 seive (c); B, transverse section of stem bark showing cork, probably secondary periderm 

 (a), cells of cortex (b) containing chloroplasts, groups of sclerotic cells (c), compressed lep- 

 tome in the outer portion of the bast layer (d), medullary ray cells (e), group of sclerotic 

 cells (f), fissures (g) between medullary ray cells and adjacent phloem tissues, cambium zone 

 (i), vessel or trachea in mature wood (k). After Bastin. 



bark is yellowish-brown. On keeping the bark for a year it 

 deteriorates from 10 to 50 per cent. 



The bark of Prunus pseudo-cerasns var. Sieholdi of Japan, 

 contains a glucoside (sakuranin) which crystallizes in needles 

 and is soluble in dilute alcohol, the solution being colored yellow 

 with ferric chloride. 



