On Animal and Vegetable Life in the Water of Leith. 233 
II. On the Animal and Vegetable Life in the Water of Leith^ d-c. 
By Dr Stevenson Macadam, F.R.S.E, 
In the bed of the Water of Leith above the influence of 
the sewage of Edinburgh, as at Gorgie dam, which is about 
a mile above Coltbridge, the stones over which the water 
flows have plants, such as moss, attached to them, and these 
plants are found on the stones in the bed of the streams con- 
veying water practically free from putrescent matter ; but 
from the entrance of the Edinburgh sewage at Coltbridge 
downwards to the harbour of Leifch, the stones in the bed of 
the stream are covered with offensive organic growths, which 
are characteristic of waters conveying sewage and capable of 
decomposing and evolving unwholesome gases. Indeed, not 
only are the stones covered with such vegetable growths, but 
everything in the bed of the river, such as arrested portions 
of trees, become thickly coated. They are also seen in the 
sewers called the Lochrin Burn sewer, the Broughton Burn, 
and the Bull's Stank sewer at Lovers' Loan as it leaves Edin- 
burgh, in all of which the bottom and sides are more or less 
covered with the growths. Even in the narrowed part of 
the channel of the Water of Leith, where the run of water 
is great, these organic matters are abundant, and likewise 
in the bottom and sides of the lade which traverses Edin- 
burgh. All the twigs and branches of trees which hang 
down into the Lochrin Burn sewer, and into the water of 
the lade, as from the gardens behind Anslie Place and Moray 
Place, have these growths adhering in long streamers, ren- 
dered bulky and doubly foul by the accumulation of entangled 
filth. These growths principally consist of those low forms 
of vegetable life which are regarded by some naturalists as 
Fungi, and by others as A Igce, and they are accompanied by 
masses of animals belonging to the family of Vorticellidce, 
including the genera Vorticella, Carchesinm, Zoothamnium, 
and E'pistylis, Much of the organic matters which are found 
entangled in the branches of trees hanging into the lades 
and open sewers, as also of the organic deposits which are 
found in the beds of the Water of Leith and of the lades, are 
composed of the decaying remains of such growths. 
