[ 240 ] 
Vertigo ; fo that he was conftrained to have it 
removed, and never after place before him but a 
fmall Piece at a time. 
There is fomething in the Formation of the Root of 
the Cicitta aquatica before-mentioned, deferving 
particular Notice. This Plant generally grows 
either near the Sides of large ftagnant Waters, or 
in (hallow Rivers, whofe Streams are flow. To- 
wards the End of Autumn, or the Beginning of 
Winter, the Root for the fucceeding Summer is 
formed out of the lower Part of the Stalk. Out 
of the Crown of this Root are then feen the Rudi- 
ments of the Leaves of next Year (fee Tab. V. 
Fig. r. a.) ; and from the Sides of this grow the 
Crowns of feveral fmaller Roots. This Root, in 
its whole Length, is divided tranfverfly into a 
Number of large unequal Cells (fee Tab. V. Fig . 2.). 
Correfponding with the Partitions, which divide 
thefe Cells, the Surface of the Root is marked 
circularly with little round Deprefllons. So great 
a Part of this Root is occupied by the Cells, that 
it becomes fpecifically lighter than Water j fo that, 
in Winter, upon the Increafe of Water in the Ri* 
vers and Pools, this Root, as well that Part in- 
tended for the fucceeding Summer, as that which 
furnifhed the Plant the preceding, is buoyed up. 
The old Root then rots, and floats upon the Sur- 
face of the Water with the new one all the Win- 
ter {fee Tab. V. Fig . i, b .) $ and in Rivers thefe 
are frequently carried to very great Diftances from 
the Places of their Growth. In the Spring the old 
Root is wafhed away 5 and the new one, upon its 
coming near the Soil, fends out from the Circles 
before- 
