THE ANIMAL PARASITES OP CATTLE. 509 



Serious objections to the use of coal-tar creosote have been found in that the sub- 

 stance known by this name varies considerably in composition and in that some 

 trouble is often experienced in obtaining it in many parts of the country. Com- 

 plaints have been made that the substance dispensed by some druggists as coal- 

 tar creosote has failed to give satisfactory results. 



Bluestone.— Bluestone, or copper sulphate, has been extensively used in South 

 Africa in the treatment of sheep and cattle for stomach worms and is recom- 

 mended by the colonial veterinary surgeon of the Cape Colony as the best and 

 safest remedy. To prepare the solution take 1 pound (avoirdupois) of pure blue- 

 stone, powder it fine and dissolve in 9| gallons of warm water. It is better to first 

 dissolve th ) bluestone in 2 or 3 quarts of boiling water, then add the remaining 

 quantity of cold water, and mix thoroughly. This solution may be given to 

 cattle in the following-sized doses: 



Calves 3ito4ounces. 



Yearlings 6 ounces. 



Two-, ear-olds and above 12 to 16 ounces. 



In making up the salution only clear blue crystals of bluestone should be used. 

 Bluestone with white patches or crusts should be rejected. It is especially im- 

 portant that the bluestone and water be accurately weighed and measured, and 

 that the size of the dose be graduated according to the age of the animal. 



Gasoline.— Gasoline is one of the most popular remedies for stomach worms 

 which have been used in this country, and has the particular advantage of being 

 readily obtained. It is important to repeat the dose if the gasoline treatment is 

 employed, and it is usual to administer the treatment on three successive days, 

 as follows: 



The evening before the first treatment is to be given the animals are shut up 

 without feed or water and are dosed about 10 o'clock the next morning. Three 

 hours later they are allowed feed and water, and at night they are again shut up 

 without feed or water. The next morning the second dose is given, and the 

 third morning the third dose, the treatment before and after dosing being the 

 same in each case. The sizes of the doses are as follows: 



Calves \ ounce. 



Yearling steers _ 1 ounce. 



The dose tor each animal is measured and mixed separately in linseed oil, milk, 

 or flaxseed tea and administered by means of a bottle or drenching tube. Gaso- 

 line should not be given in water. 



Other remedies. — Many other remedies in addition to those mentioned hsre 

 have been used in the treatment of stomach-worm disease with more or less suc- 

 cess. Several of the coal-tar dips on the market are recommended by the manu- 

 facturers for the treatment of worms, and the action of some of them is much 

 the same as that of coal-tar creosote. 



It is not the policy of the department to recommend the use of any particular 

 proprietary remedy, and as the action of some such agents is very uncertain it is 

 suggested that, if it is desired to use them, they be used with caution and only in 

 accordance with the printed directions on the package. Whatever remedy is 

 used it is wise to test it on two or three animals before the entire herd is dosed. 



The Encysted Stomach Worm (Ostertagia ostertagi). 



This parasite is as thick as a fine hair and less than half an inch 

 in length. It lives in small cysts in the wall of the fourth stomach 

 (fig. 19) and is also found free in the cavity of the stomach. When 



