PARASITOLOGY. 189 



Animal Infested. — The adult infests the dog ; the 

 larva infests sheep, and, rarely, cattle. 



Parts hikstcd. — The adult worm infests the small 

 intestines of the dog ; the larval or cystic form is 

 found in the brain or spinal cord. 



Disease Produced. — Gid ; turnsick; sturdy; water- 

 brain. 



Sympto77is. — A dog infested by the adult worms 

 shows the same symptoms as when infested by any 

 one of the preceding species, and is amenable to tk€ 

 same treatment. If many embryos become lodged in 

 the cranial cavity of the sheep the first symptoms will 

 appear about the eighth or tenth day ; they cause a 

 cerebral congestion which produces dullness ; the 

 head is held in a drooping position, the eyes are red, 

 and the head hot over the affected region ; there may 

 be spasms and paralysis. If only a few embryos 

 are present they will not produce the symptoms so 

 quickly ; later the sheep keeps apart from the flock, 

 the pupils are dilated, and the animal manifests an 

 imsteady gait ; the animal may turn in a circle, to 

 the right or left, depending on which side the cysts 

 are developed ; if the cysts are in the right hemis- 

 phere it will turn to the right; if in the left hemis- 

 phere it will turn to the left. The limbs on the 

 opposite side of the body are stiff or partially para- 

 lyzed ; if both hemispheres are invaded the sheep 

 may turn to the left, then to the right, depending 

 upon which side the greatest irritation exists ; if the 

 cysts are in the center, in the region of the corpus 

 callosum or hippocampus the sheep elevates its nose 

 and goes straight forward ; if the cysts are lodged in 

 the cerebellum they produce great incoordination of 

 movements ; if in the corpus striatum or optic thai- 



