588 Dr. DAvBENY on a certain Kind of 
deposit, which have served to throw a certain air of mystery 
over its nature and origin. 
I am therefore induced to lay before this Society a drawing *, 
which represents the appearances exhibited, under a micro- 
scope of Amici’s construction, by an organic substance which 
I obtained last summer at the hot spring of Greoulx in Pro- 
vence (departement des Basses Alpes). ‘This-matter was found 
everywhere on the pavements of the bathing-rooms, in parts 
exposed to the splashing of the thermal water, which, for 
the convenience of topical bathing, or the douche, is usually 
allowed to descend in a constant stream from an open pipe, 
communicating with the reservoir which receives the mineral 
water, and terminating just below the ceiling of the room, 
through which it passes in a direction nearly perpendicular. 
The substance alluded to, seen by the naked eye, has a green- 
ish tinge, and seems made up of bundles of filaments: under 
the microscope, however, the latter are magnified into long 
cylindrical tubes, almost transparent, and divided into articuli, 
the length and diameter of which appear nearly equal, filled 
with a darkish fluid, whilst the intervening spaces are nearly 
colourless. This appearance may, perhaps, be explained by 
supposing a double tube, the exterior one transparent and con- 
tinuous throughout, the interior composed of articulations filled 
with a coloured matter, and distinct one from the other, in con- 
formity to the general structure of Conferve, as laid down by 
Bory de St. Vincentt and others. ‘These same filaments are 
sometimes so disposed with reference one to the other, as to pre- 
sent a stellated appearance of greater or less regularity. 
. In fig. 5. of the plate representing Arthrodie, which is given 
in the 2nd volume of the Dictionnaire Classique d'Histoire 
* The drawing is deposited in the Library of the Society. 
+ Dict. Classique d' Hist. Nat., article * Arthrodiées." 
Naturelle, 
