148 
from this country, I was informed that many were bent into 
a horse-shoe shape, and could merely go round and round as if 
the spine were diseased. Curiously the experiments here 
described seem to elucidate the cause of this pathological state, 
as four alevins in succession from peat tray No. 6 (and which 
have been already referred to,).were hatched in this condition. 
The first question was, whether the presence of peat exercised 
any influence directly or indirectly on these results? But that 
it had any direct influence may be at once negatived, because 
similar conditions were present in young which had not been 
exposed to peat in any way. But that it indirectly was the 
cause seemed to be probable, for it had been necessary to 
constantly wash these eggs in order to prevent the embryos 
being suffocated, consequent upon the peaty deposit. In fact, 
it was doubtless due to concussion in its somewhat lesser 
degree, possibly first occasioning spinal irritation which de- 
veloped into disease. On placing one under the microscope on 
March 19th, it was evident that the bodies of some of the 
vertebree were affected as seen in hog-backed trout. Mr 
Wethered has been good enough to photograph one of these 
fishes under the microscope, and the figure gives an excellent 
idea of the appearances observed. In one of those hatched, 
the body formed a complete circle, and it appeared to spin 
round and round when attempting to swim; the others were 
more of a horse-shoe shape. Such fish, as a rule, never survive 
the alevin stage, but exceptions occur, as has been observed in 
an example at Delaford last year. (3 photographs exhibited.) 
The question of the depth of water in which Salmonoid eggs 
can be incubated is by no means an unimportant one. It is 
said that in salmon rivers fish which ascend late to deposit 
their spawn root up the nests of the first comers, and as a con- 
sequence the eggs are carried away down stream to be eaten by 
their enemies or perish in the deep water below the ford. I 
admit that more complete experiments are required, for I 
merely had sufficient depth to try the effects at 26 inches. 
Experiment No. 14.—December 14th, 1885, at 1 p.m., took 
a paraffin cask (which had been well charred inside and kept 
