IIG AURANTIACE^. 



ing 2 or 3 seeds. It abounds in a pale-yellow acid jnice liaving a 

 pleasant sour taste and a slight peculiar odour quite distinct from that 

 of the peel. When removed from the pulp by pressure, the juice appears 

 as'a rather turbid yellowish fluid having a sp. gr. which varies from 

 1-040 to 1-045, and containing in each fluid ounce from 40 to 46 grains 

 of citric acid, or about Qi per cent.' In Italy all the fine and perfect 

 fruit is exported; the windfalls and the damaged fruit are used for the 

 production of the essential oil and the juice. About 13,000 lemons of 

 this kind yield one pipe (1 08 gallons) of raw juice. Sicilian juice m 

 iNovember will contain about 9 ounces of citric acid per gallon, hut 

 6 ounces when aflbrded by the fruit collected in April. The juice is 

 boiled down in copper vessels, over an open fire, till its specific gravity 

 is about 1-239.'^ Lemon juice {Succus limonis) for administration as a 

 medicine should be pressed as wanted from the recent fruit whenever 

 the latter is obtainable. 



The peel {GoHex limonis) cut in somewhat thin ribbons from the 

 fresh fruit is used in pharmacy, and is far preferable to that sold m r 

 dried state. 



Microscopic Structure of the Peel. — The epidermis ex 

 numerous stomata ; the paronchyme of the pericarp encloses large oil- 

 cells, surrounded by small tabular cells. The inner spongy tissue is 

 built up of very remarkable branched cells, separated by large inter- 

 cellular spaces. A solution of iodine in iodide of potassium imparts to 

 the cell-walls a transient blue coloration. The outer layers ot tlie 

 parenchymatous tissue contain numerous yellowish lumps of a substaiic 

 which assumes a brownish hue by iodine, and yields a yellow solution 

 if potash be added. Alkaline tartrate of copper is reduced by tlu^^^^' 

 stance, which probably consists of hesperidin. There also occur i&r 

 crystals of oxalate of calcium, belonging to the monoclinic system, -i" 

 mterior tissue is irregularly traversed by small vascular bundles. 



Chemical Composition— The peel of the lemon abounds in es.sen- 

 tial oil, which is a distinct article of commerce, and will be descriueu 

 nereatter. 



a 



hihits 



^ Lemons, as well as other fruits of the genus Gitru.s, ^...^ ^^^ . 



principle, Hesperidin, of which E. Hoff*mann^ obtained 5 to 8 per ce^^^- 

 trom unripe bitter oranges. He extracted them with dilute alcon j 

 alter they had previously been exhausted by cold water. Tlf aico 

 should contain about 1 per cent, of caustic potash; the liquid on ^o 

 ing IS acidulated with hydrochloric acid, when it yields a jf<>''\ 

 cr^^^tallme deposit of hesperidin, which may be obtained colourless 

 tasteless by recrystalhzation from boiling alcohol. By dilute sulplH^'" 

 acid (1 per cent.) hesperidin is broken up as follows: 



Hesperidin. Hesperetin. Glucose. 



Hesperidin is very little soluble even in boiling water or in ethej-,b^^^ 

 dissolves readdy in hot acetic acid, also in alkafine solutions, the h t^^^^ 

 then turning soon yellow and reddish. Pure hesperidin, as pre^eii 



3S5 '"^"""S*""' ^''«™^- Jonrn. v. (1875) schaft (1876) 26, 685, 693. 



