808 
EDITORIAL OBSERVATIONS. 
to this query appears to us to be obvious enough. Excess of 
moisture cannot produce the ova of parasites, in fact, there is 
only one possible origin for them, and that is the generative 
system of the mature female worm. It seems, therefore, to 
follow that this source of supply exists more generally than 
is commonly supposed ; and so long as the circumstances are 
opposed to the development of the germs no harm results, 
and nothing occurs to call the attention of the owner of 
stock to the fact that there are several sheep of his flock 
which are affected with strongyles or flukes to a sufficient 
extent to infect the land on which they are grazing, provided 
that the one indispensable condition, wet, be present. 
Flukes in the liver of the sheep, and strongyles in the lungs 
of calves and lambs, do not necessarily produce so much de¬ 
rangement as to attract the notice of an ordinary observer, 
and they exist even without being detected by a skilled 
examiner; it is therefore possible that an animal in apparent 
health may harbour these parasites, and thus become a 
means of infecting other animals without any suspicion of 
the true source of mischief being excited. 
The history of parasitic diseases proves that the germs of 
new generations are widely spread, surely to spring into active 
existence when the surrounding conditions are favorable, but 
harmless enough until those conditions arise. Under the pre¬ 
sent circumstances stockowners should be very suspicious of 
the existence of parasites whenever a strange disorder appears 
in the flocks and herds. Several instances have come under 
our notice of young cattle having been condemned as suffer¬ 
ing from pleuro-pneumonia, on account of the husky cough, 
when a further examination has shown that they were the 
victims to strongyles in the bronchial tubes, and we should 
be afraid to calculate how many cattle, in the course of the 
last few years, have been condemned, by incompetent persons, 
as the subjects of a disease which had no actual existence. 
Latterly the subject of parasitic disease has formed a 
part of the curriculum at our veterinary schools, and we 
anticipate that the diffusion of the knowledge of this im¬ 
portant section of veterinary medicine will tend to the saving 
of many valuable animals. 
