Parasites and Parasitic Diseases of Sheep. 41 
other opening near the bottom of the inverted jar, to equalize air pres- 
sure. This is shown in figure 25. The flow into and out of the 
glass tube is controlled by pinchcocks, one person attending to this 
and one holding the metal tube in the sheep’s mouth. The sheep 
should remain on all four legs, with the head held horizontally while 
it is being drenched, which decreases the danger of getting the drench 
- into the lungs and killing the sheep. The solution should be allowed 
to flow slowly and the metal tube be moved about slightly in the mouth 
at the same time in order to keep the sheep swallowing. It is essen- 
tial that the copper-sulphate solution be made up accurately, be given 
in suitable doses, and be administered with care, and it is advisable 
to have a competent veterinarian give this treatment or the ones 
noted below in order to insure a maximum degree of safety. 
The sodium-arsenite and copper-sulphate mixture and the copper- 
sulphate and tobacco solution, recommended for tapeworm, have 
also been recommended as effective against stomach worm (p. 22). 
Prevention.—Preventive measures are based on the life history. 
We know that the disease is spread by eggs produced by the female 
worm, which escape in the manure on to the pastures. Infested sheep 
must be regarded as a danger to young and uninfested sheep. The 
manure an the infested sree is likewise dangerous. Consequently, 
young animals and uninfested sheep should be separated from older 
or infested animals and not exposed to contact with the manure from 
these animals. Furthermore, pastures which have been used by in- 
fested animals are dangerous to young animals and uninfested ones. 
When animals that have stomach worms, either in a light or heavy 
infestation, are put on clean pasture, the eggs of the stomach worm 
will hatch on the ground and the infective stage of the worm will be 
present on the grass in considerable numbers in from 10 to 20 days, 
or even earlier in warm weather. The longer the sheep are on that 
pasture under ordinary weather conditions the more dangerous it 
will become from the increasing number of worms. To prevent get- 
ting dangerous infestations, it is advisable that sheep be moved ev ery 
two weeks to clean pasture. Inasmuch as pastures probably remain 
infected for about a year after sheep, goats, or cattle are moved from 
them, the program of moving sheep to new pasture, where permanent 
pastures are used, is a rather difficult one and calls for more land than 
is usually available. Consequently a modification of this program is 
necessary. 
The first essential is to protect the lambs. Young animals are more 
susceptible to parasitic infestation than older ones. They also suffer 
more from parasites when they are infected. Growth must be made 
during youth; it can not be made up in mature years. Parasites in- 
terfere seriously with growth and lead to the production of runts. 
Consequently the safest pasture should be furnished to the lambs, 
