ON A DIRECT METHOD OF OBTAINING IODINE. 
343 
machine, prepared for the purpose, which would have re- 
duced these slices to a pulp, thus effectually breaking up 
the cellular tissue, and then proceeding to express the fluid 
and liberate the iodine as in the type experiment. Nature 
however interposed to save the trouble, for the mass of 
slices having been left in a heap for about twelve hours, a 
species of fermentation commenced, with evolution of heat 
and other phenomena, which reduced the whole mass to a 
pulp without further trouble ; and this mass being submit- 
ted to adequate pressure, completed the object in view. 
The fibrous tissue left in the press still contains iodine ; but 
the pressed mass is so easily charred at a low temperature, 
that on a large scale this method will no doubt be preferred 
to the more circuitous course. 
With reference to the Laminaria saccharina, which in 
the autumn is very rich in iodine, the plan of extraction is 
still simpler. Having collected this, as drift-weed, it is only 
necessary to heap it up in vats, or other receptacles of ade- 
quate size, with a tap at the bottom to allow the liquid to 
escape. For some hours nothing but sea-water runs off ; 
at a certain stage, however, and time, mainly dependent 
upon quantity and temperature, active fermentation sets in- ? 
and as it is presumed that the liquid running off is careful- 
ly tested for iodine from time to time, immediately its ap- 
pearance is indicated the tap should be closed, and during 
the next twelve hours the contents of the vat should be oc- 
casionally moved or stirred about. When the contents have 
been reduced to a soft pultaceous magma, in which all re- 
maining cellular tissue can be readily broken down by the 
hand, the addition of quicklime in sufficient quantities, 
which will vary with the amount of substance operated 
upon, but may easily be determined by experience, com- 
pletes the process; and in this case almost the whole of the 
iodides in solution may be removed by expression. In locali- 
ties where lime is e xpensive, the process of charring may be 
resorted to. 
