ALMOND. 11 



The outer wall, usually smooth and somewhat thicker than the inner 

 and lateral walls, is sometimes flattened, but often protrudes as 

 rounded papillae. It is usually free from pores, though pores were 

 noted in a few instances. The papilla have been regarded by some 

 investigators as representing hairs, 1 an opinion confirmed by their 

 appearance in many cases. They vary considerably in height, some 

 having been found near vascular bundles projecting 400 \L above the 

 surface of the seed coat (PI. I, fig. 1). 



The parenchyma layer of the spermoderm is lacking in distinctive 

 character, and the cell outlines are very indistinct. Its color is 

 yellow or brownish. As in the soft-shelled almond, rosette crystals 

 ajje present in some nuts and absent in others, but are more numerous 

 than in that variety. The endodermis closely resembles that of the 

 soft-shelled almond, but the cell walls are even more delicate and 

 difficult to see. 



The hyaline layer constituting the perisperm is about 5 \L thick 

 and is adjacent to the aleurone layer, which varies up to 85 {x thick, 

 consisting usually of a single layer of cells. In surface view these 

 cells are indistinguishable from those of the soft-shelled almond, and, 

 as in that variety, they vary considerably in size. When the tissue 

 is treated with alkali or chloral hydrate the walls become swollen 

 and somewhat indistinct, and the central lamina comes into view. 

 (PL I, fig. 3.) 



The epidermis of the cotyledons consists of oblong parallel cells 

 averaging about 35 by 8 p. (PL I, fig. 4.) The tissues of the 

 cotyledons can not bo distinguished from those of the soft-shelled 

 almond. 



The bitter -almond is practically identical in structure with the 

 hard-shelled sweet almond described above. 



ADULTERANTS AND SUBSTITUTES. 



In localities where peaches and apricots are grown extensively for 

 drying, as in sections of California, the disposal of the pits presents 

 a problem of interest to both the fruit grower and the consumer of 

 almond products. The experiment of removing the pits from 

 prunes previous to drying has recently been made, and should this 

 process prove a financial success prune pits will eventually take their 

 place beside those of the peach and apricot. This class of by-prod- 

 ucts was formerly used only for fuel, but more recently there has 

 been an increased demand, especially for apricot pits, and investi- 

 gation reveals the fact that in certain cases the kernels are substi- 

 tuted for bitter almonds. They are even exported to Europe, where 

 the essential oil is distilled and mixed with or substituted for the oil 



1 Wittmack and Buckwald, loc. cit., p. 590. 



