S78 Medical Botany. 



much labour would be required. To convert it to use, it is slowly baked 

 on live coals, and being thus I'endered porous and hard, is ground into 

 powder, which is kneaded with water into cakes, and baked in an oven. 

 The Siberian ermine hunters, when their yeast, which they carry with them, 

 to make their quass, is spoiled by the cold, digest the inner bark of the 

 pine, with water, over the fire, during an hour, mix it with their rye-meal, 

 bury the dough in the snow, and, after 12 hours, find the ferment ready pre- 

 pared on the subsiding faeces. 



Canada Balsam is the produce of the Balm of Gilead Fir, and differs little 

 from the celebrated Balm of Gilead, which is extracted from .^^myris 

 gileadensis. 



The Thv.s, or common frankincense of the shops, is resin which spon- 

 taneously exudes in drops from the common spruce fir. Some writers, 

 observes Dr.Maton, are of opinion, that the genuine frankincense is obtained 

 from J^uniperus lycia, and is the Olibanum of our shops ; but it is more pro- 

 bable that it is only what exudes spontaneously from the spruce fir. 



Burgundy Pitch is prepared from the resinous juice of the common 

 spruce, which exudes from incisions made in the bark. This soon concretes 

 in the air, is collected, and afterwards melted, with water, in a cauldron over 

 a slow fire, strained by pressure, and thus prepared for sale. 



The best Turpentine, after that of Pistacia Tferebinthus, and also the Ve- 

 nice turpentine, are made from the larch. Holes are bored in the trees in 

 Ma}', from which the juice runs into troughs. 



Besides the Venice turpentine, the larch also yields the Gummi Orenbuv- 

 gense of the Russian shops, which is described as a good substitute for gum 

 arable. The mode in which this substance is obtained is remarkable. It 

 sometimes happens that whole forests of larch are accidentally consumed 

 by fire. During the combustion of the medullary part of the trunks, a gum 

 issues forth, which is collected by the natives, for the purpose, not only of 

 rendering their bows glutinous, but also of being eaten as a delicacy. It is 

 also supposed to act as antiscorbutic, and a useful astringent for the gums. 



The Manna of the Larch is thus procured. About the month of June, 

 when the sap of the tree is most luxuriant, it produces small white drops, 

 of a sweet glutinous matter, like Calabrian manna, which are collected by 

 the peasants early in the morning before the sun dissipat^ them. It is 

 inferior as a drug, to that of the Calabrian ash. 



^■- The important uses of these different substances in medicine and in the 

 arts, are well known. 



No. XX. for August, contains 



76 to 79. — Acacia Catechu, from the mountainous districts of Hindoo- 

 stan, and used in medicine, in the form of extract, in disorders in which a 

 mild, unirritating, powerful astringent is required. In the East it is used 

 with the betel nut for chewing. — Jcacia vera, a shrub from Upper Egypt, 

 which furnishes the gum arable of the shops. " The purest and finest gum 

 arable is brought in caravans to Cairo, by the Arabs of the country round 

 Mounts Tor andSinai, who bring it from this distance on the backs of camels, 

 sown up in bags, and often adulterated with sand and other matters. The 

 gum exudes spontaneously from the bark of the trunk and branches of the 

 tree, in a soft, nearly fluid state, and hardens by exposure to the air, or heat 

 of the sun. It begins to flow in December, immediately after the rainy 

 season, near the flowering time of the tree. Afterwards, as the weather 

 becomes hotter, incisions are made through the bark, to assist the transu- 

 dation of the juice. 



Mercurialis perennis. A native perennial, common in shady groves and 

 hedges, with a very nauseous taste, a heavy disagreeable smell, and considered 

 poisonous. — - Mercurialis annua is also a very common native. It is muci- 

 laginous, and was formerly employed in fomentations. It may be eaten 

 as spinach ; but, if used in considerable quantities, it operates as a cathartic. 



