EDITORIAL OBSERVATIONS. 
m 
hecessarv for the introduction of liver-fluke into anv pasture : 
1st. There must be sheep infested with the parasite, and 
containing what may be termed the seeds of the disease. 
2nd. There must already exist, either in the pastures, water- 
holes or rivers a certain class of snails specially organised to 
act as hosts for the embryo, or, in other words, as receptacles 
for these seeds. If either are absent fluke cannot be repro¬ 
duced. These facts fully account for the total absence of 
fluke during many years from a portion of this district now 
seriously infested by it, and also for the positively ascer¬ 
tained impossibility of reproducing fluke on the salt plains 
pastures. I have it on unquestionable authority that for 
many years fluky ewes, in lamb, were annually removed 
from this district to the westward plains, and that though 
they bred there for three or four years afterwards, yet 
liver-fluke was never found in their offspring. My informant 
further states that the change of pasture did not rid the 
mother sheep of her unpleasant guests, but their ova being 
scattered on what I may term barren ground, perished there 
for want of congenial hosts, and the lambs of the fluky 
ewes invariably remained sound. Dr. CobbokTs theory 
explains also why after unusually wet seasons fluke is more 
prevalent in our flocks in this district, and on the contrary in 
dry seasons the same district is comparatively free from the 
disease. All the snail tribe increase very much in moist 
weather; a larger number of the ova are therefore deve¬ 
loped, and taken up by the sheep; an abundant crop natu¬ 
rally follows a plentiful supply of seed, whilst in dry 
weather the nurses become scarce and a large portion of the 
ova perishes for want of them. 
“ Various remedies have been suggested for the cure and 
prevention of this terrible scourge of our flocks. Two only 
are worthy of observation, as they are now in general use 
by owners of infested flocks. The first is a constant and 
liberal supply of rock salt placed in troughs in every paddock 
wherein sheep are depastured; and the second is a compound 
of sulphate of iron and common Liverpool salt in the pro¬ 
portion of one part of the former to five parts of the latter. 
The iron and salt remedy was introduced some years ago by 
Mr. Charles Thomas, a very old colonist and the brother of 
VOL. XLV1 . 9 
