-FUC—FUC_ 157 
2. Ulva umbilicalis. Shield Layer. Esculent, but requires 
baking for some hours, to render it eatable. = 
3. Ulva linza. 
4. Ulva latissima. Iceland sea-grass. 
5. Ulva lactuea. Called also Lichen marinus ;—Oyster-green; 
attached to salt water oysters. Refrigerant ; also nutritive. 
Iodine has also been obtained by Dr. Fyfe, and Mr. Straub, 
of Hofwyl, from the sea-plant we call sponge, or i 
officinalis. Burnt sponge had long been efficiently em- 
ployed in goitre and other similar glaudular enlargements, _ 
efore the discovery of iodine. It does not yield it large- 
‘ly; probably contains other principles besides. 
Iodine is a simple body, discovered in 1813, by Mons. 
Courtois, in the mother water of soda, as obtained from the 
different plants enumerated. The name is derived from . 
the Greek word sadie, on account of ‘the blue or violet 
colour of its vapour. 
Cabinet specimen, Jeff. Coll. No. 310. 
Meprcat Prorertres ann Uszs. Is solid at the ordinary 
temperature, in the form of small greyish crystals, which 
resemble plumbago; has little tenacity. It fuses at 338° F, 
yolatilizes at 347° F.; forming a beautiful violet-coloured 
vapour, called violaceous AInclosed in a receiver, this 
becomes re-condensed into crystalline scales, or into 
jodine again ; is soluble with alcohol and ether ; the tr. for 
medical use is made with alcohol; water dissolves only the 
seven thousandth part. It forms acids with hydrogen 
(Hydriodic acid) and oxygene, (iodic acid). Has great — 
affinity for hydrogen, uniting with it ina gaseous state, — 
when the temperature is elevated, and takes it from other 
bodies greedily. This hydriodic acid, is rapidly absorbed 
by water, and largely dissolved in it; gives Gut white fumes 
on throwing it in the air, uniting with its aqueous vapour; 
forms neutral salts, with many bases—as hydriodate of 
potash, with that salt, (much used in medicine )—Hydrio- — 
date of soda, with that salt ; this also has been medici 
used. Lodine corrodes metals quickly, and hydriodic on ty 
which is a colourless gas, reddens tr. of turnsole, and ex. © 
tinguishes flame. 
Mode of uring Iodine.—It exists in the mother waters, 
ee econ of soda, from Fuci, reduced to 
kelp, by burning, in the state of hydriodate of potash ; 
after the Fuci, which grow abundantly on the sea-shore 
of Normandy, are incinerated, the ashes are lixiviated, and 
the liquor concentrated, To procure the iodine, an excess 
of sulphuric acid is added to these waters, and the liquor 
Same 4 boiled in a glass retort to which a receiver is 
attached. The decomposition which results, by the union 
02 
