558 DISEASES OF CATTLE, SHEEP, GOATS, ETC. 



This danger may be minimized, or entirely prevented, by the 

 addition of commercial copperas, after the solution has been ren- 

 dered excessively alkaline through the addition of air-slacked lime. 



The clear solution left on top, after the addition of the cop- 

 peras solution, should contain no arsenic, and may, with safety, be 

 pumped, or syphoned, to any convenient place; and the sediment 

 remaining buried in a small hole dug for the purpose. Air-slacked 

 lime and copperas are quite inexpensive materials, and easily ob- 

 tainable by anyone. The amounts suggested of the materials are 

 sufficiently in excess to be effective in any strength of arsenical solu- 

 tion now in use. 



This method is simple, effective, and inexpensive, and if 

 adopted, may be the means of preventing casualties from the care- 

 less disposal of the poisonous arsenical solution, especially when un- 

 dertaken, at the time of emptying the dipping-vat for cleaning at 

 the end of the season, or at other times, by those who may not be 

 conversant with its poisonous nature. 



INTERNAL PARASITES. 



THE BLADDER WORMS (TAENIA MARGINATA J BATSCH). 



On dressing sheep and lambs it happens sometimes that the 

 folds of the omentum or caul will contain a number of semi-trans- 

 parent bladder-like bodies from a half to one inch in diameter. A 

 similar condition may be found on the brain due to another variety 

 of the parasite. These bladders contain a worm known as the 

 bladder worm and are one stage in the development of the tape 

 worm. 



The Taenia marginata, Batsch, is the variety affecting the ab- 

 dominal cavity. In from one to two weeks after sheep ingest the 

 eggs of this parasite, the young will have developed and migrated 

 from the intestinal canal and a favorite place for them is on the sur- 

 face of the liver. They may migrate from any part of the intestinal 

 tract and therefore may be found at any place along its course. The 

 bladders are composed of a delicate, whitish membrane and when 

 viewed toward the light, one point will appear to be denser than the 

 rest. As these bladders grow this spot becomes thicker and denser. 

 This is the head and the part by which it is attached to the cyst wall. 

 This head is fully developed with hooks and suckers, and when 

 freed becomes the starting point for the development of the mature 

 state in some other animal. The parasite requires about two weeks 

 from the time of the ingestion of the eggs to develop and migrate 

 through the intestinal wall. It requires about eight weeks more to 

 develop into mature cysts, but when matured as cysts they may re- 

 main in this condition for a long period of time. This is as far as 

 the parasite ever develops in the sheep. To complete its life cycle 

 the sheep, when it is killed or dies, must be eaten by a dog, wolf or 

 other carnivorous animal, the cyst is ruptured and the head attaches 

 itself to the intestinal wall and begins to develop into the form 

 known as the tapeworm. The tapeworm becomes fully developed 

 in from ten to twelve weeks, and the young worms in the form of 



