iQO CITRUS MEDICA. 
will appear in thin needle-like crystals, assuming the form of rhom- 
boidal prisms; these crystals suffer no change from exposure to 
the air, and have an exceedingly acid taste. When sufficiently 
heated, they melt, swell, and emit fumes, and are partly sublimed, 
unchanged, and partly decomposed ; water at the ordinary tempera- 
ture dissolves one half its weight of this acid, at twice its 
weight; the solution undergoes spontaneous decomposition very 
slowly; sulphuric acid clears it, and forms vinegar; nitric acid 
converts it into oxalic and acetic acids. Citric acid being more 
costly than tartaric, is occasionally adulterated with it. 
Medical PROPbRXiKS and Uses. The rind of the lemon 
being similar in its properties to that of the orange, may be em- 
ployed with the same intention, and in the same manner, m the 
making of stomachic tinctures and infusions. Lemon juice is a pow- 
erful and agreeable antiseptic ; Dr. Wright says its powers are much 
increased by saturating it with muriate of soda, (common salt) and 
this mixture he recommends as possessing great efficacy in dysen- 
tary, remittent fever, putrid sore throat, &c. Lemon juice is one 
of the most powerful antiscorbutics among the vegetable acids, and 
with this view has long been used in the British navy, when the 
crews are at sea and confined to the use of salt provisions. We 
have even known scorbutic sores to be washed with it with good 
effect, and perhaps its application in this way might be found ser- 
viceable with other ill-conditioned sores. Scorbutic gums are much 
benefited by washing the mouth with it. But the most general-use 
to which lemon juice is applied medicinally, is in combination with 
the alkalies which it neutralizes. These mixtures are almost uni- 
versally given to fever patients, and are found extremely grateful ; 
allaying thirst and febrile heat, and promoting diaphoresis; the most 
common mixture of this kind is a solution of the carbonate of soda 
in water, (four drachms to eight ounces of water) an ounce of which, 
with half an ounce of lemon juice may be frequently taken m the 
course of the day: on the mixture of the acid and the alkaline solu- 
tion a considerable effervescence takes place, occasioned by the 
acid combining with the soda, and expelling the carbonic acid gas; 
it is hest to take it during this effervescence, particularly if there is 
any sickness of the stomach, which will be relieved by the carbonic 
acid gas, and these effervescent mixtures are not unfroquently given 
merely to allay sickness : one ounce of lemon juice will generally be 
found sufficient to saturate a drachm of the alkali. The carbonate of 
potass is sometimes used instead of the soda ; and sometimes also a 
solution of the carbonate of ammonia in water. The crystals may 
