228 DISEASES DUE TO INTERNAL PARASITES. 



market to the infection, so that the period of feeding would be 

 shortened, and the profits correspondingly increased. Among 

 the first noticeable symptoms will be a dullness and a pale ap- 

 pearance of the mucous membranes of the eyelids, nasal cavity 

 and mouth; the membrana nictitans, or winking eyelid, situated 

 at the corner of the eyes nearest the nose, -becomes yellow. 



As the disease progresses the affected sheep become flaccid 

 about the loins, and commence to shrink; by passing the hand 

 over the hips a crackling sovmd is produced, caused by the pres- 

 ence of gases in the sub-cutaneous connective tissue ; the counten- 

 ance becomes pale, the skin changes color from the normal 

 healthy pink hue to a pale red, the wool parts easily from the 

 skin, which as the disease progresses becomes covered with 

 yellow and black spots; in a short time the dullness increases, the 

 animal continues to lose flesh, the paleness of the mucous mem- 

 branes increases until they become almost white, at which stage 

 they commence to become yellow, showing the presence of bile 

 in the blood; the yellow appearance extends to the skin, which 

 now becomes loose and flabby, a watery fluid collecting under it, 

 dropsical swellings being noticeable under the belly between the 

 fore-legs and under the jaw. This last appears in the form of a 

 large watery swelling, giving the sheep the appearance termed 

 "checkered." "When this stage is reached the sheep quickly 

 succumbs. 



Duration of the Disease. 



Some authorities state that the flukes remain nine months, 

 others claim fifteen months in the affected sheep, and that after 

 this time they gain access to the intestinal canal and are voided 

 with the droppings. 



Thomas says he has seen the sickness last six years, Neu- 

 mann claiming, as does Perroncito, that the flukes rarely quit 

 their hosts, and the question of re-infection of the same animal 



