96 
Parasites of Cattle and Sheep. 
by the bronchial strongyle. They will very much depend on 
the extent to which the lung tissue is invaded by the embryos. 
The sheep lags behind its fellows, tends to separate itself, is 
disinclined to move, and pants and coughs after any exertion ; 
generally there is some thirst. When the lungs are extensively 
invaded the course is usually short, and death may occur a few 
hours after indisposition is first observed. When only a very 
limited area of lung is affected the course of the disease may 
be protracted, and fresh accession of symptoms follows fresh 
invasions by embryos. The disease is not always fatal, for 
lungs of sheep wholly unsuspected during life, are frequently 
found to contain considerable areas of solid lung attributed to 
attack of the embryos of this worm. 
Prevention . — Concerning the life-history of the lung 
strongyle we are no more favourably placed than in the case 
of the other members of the strongyle family. Preventive 
measures, we think, must follow on the principles suggested 
in the case of other diseases due to strongyles. In the expe- 
rience of a good many people the disease induced by the 
Strongylus rufescens is limited to over-stocked sick-sheep 
enclosures. We have confronted it on Salisbury plain and 
in other places where wide range of pastures is the rule, but 
investigation has usually shown that the subjects of the disease 
have been purchased and not bred in open country. 
The consideration of curative treatment does not afford very 
good grounds for hope. When sheep are showing symptoms 
of the disease, the lung tissue is invaded by the embryos, and 
we know of no medicine which is likely to destroy them. 
Indeed, if there are reasons for thinking many sheep are 
infested, it is probably best and most economical to have the 
flock slaughtered. Good dry food is essential, and shelter from 
cold and exposure should be provided. 
Gid, Sturdy, &c. — The affection so well known as “ gid,” 
“ sturdy,” “ turnsick,” “ goggles,” &c., is very general and 
certainly one of the best understood diseases of sheep. The 
symptoms, so well expressed in the popular names, are due 
to the presence in the brain or spinal cord of the sheep of 
a cyst or bladder, the Ccenurus cerebralis or gid hydatid. 
This represents one phase in the development of a tapeworm 
( Tcenia ccenurus ) which inhabits the intestine of the dog. 
The cyst or bladder, which may attain the size of a hen’s 
egg, is filled with a watery fluid, and contains, usually in 
contact with its inner lining membrane, many heads, each of 
which under favourable circumstances becomes an individual 
tapeworm. Each bladder may enclose hundreds of heads, so 
that if a dog swallowed one of these cysts, it is possible that 
a large number of tapeworms may develop in his intestines. 
