INFECTIOUS DISEASES OF CATTLE. 505 



In the use of arsenical dips care should be taken not only to avoid 

 swallowing any of the dip. but persons using the dip should also bear 

 in mind the possibility of absorbing arsenic through cuts, scratches, 

 or abrasions of the skin, and the possibility of absorbing arsenic by 

 inhalation of vapors from the boiler in which the dip is prepared, 

 or by the inhalation of the finely divided spray when the spray pump 

 is used. It should be remembered that the absorption of even very 

 small quantities of arsenic if repeated from day to day is liable 

 ultimately to result in arsenical poisoning. 



Cattle should always be watered a short time before they are 

 dipped. After they emerge from the vat they should be kept on a 

 draining floor until the dip ceases to run from their bodies; then 

 they should be placed in a yard free of vegetation until they are 

 entirely dry. If cattle are allowed to drain in places where pools 

 of dip collect, from which they may drink, or are turned at once on 

 the pasture, where the dip will run from their bodies on the grass 

 and other vegetation, serious losses are liable to result. Crowding 

 the animals before they are dry should also be avoided, and they 

 should not be driven any considerable distance within a week after 

 dipping, especially in hot weather. If many repeated treatments are 

 given the cattle should not be treated oftener than every two weeks. 



In addition to properly protecting vats containing arsenical dip 

 when not in use, another precaution must be observed when vats are 

 to be emptied for cleaning. The dip should not be poured or allowed 

 to flow on land and vegetation to which cattle or other animals have 

 access. The best plan is to run the dip in a pit properly protected by 

 fences. The dip should also not be deposited where it may be carried 

 by seepage into wells or spring which supply water used on the farm. 

 The same precautions should be observed when animals are sprayed 

 as when they are dipped. 



Crude fetroleum. — Various kinds of cnide petroleum have been 

 used with more or less success in destroying ticks. The heavier vari- 

 eties of oil are very injurious to cattle. On the other hand, the very 

 light oils are so volatile that their effects last but a short time, thus 

 i^ndering them less efficient. The petroleum known as Beaumont oil, 

 obtained from Texas wells, has given the best results. The best grade 

 of this oil to use is one that has a specific gravity ranging fi*om 22^° 

 to 24^° Beaume, containing 1^ to 1^ per cent of sulphur, and 40 per 

 cent of the bulk of which boils between 200° and 300° C. The oil 

 may be applied by employing a spray pump or a dipping vat. 



Animals that have been dipped in crude oil, especially during 

 warm weather, should not be driven any great distance immediately 

 afterwards, and should be provided with shade and an abundance 

 of water. Unless these precautions are observed serious injury and 

 losses may result. 



