222 ELEMENTAEY AGRICULTURAL CHEMISTRY 



soda, contains about 66 per cent, of arsenious oxide.* If diluted 

 so as to contain about 1 lb. of arsenious oxide in 40 or 50 

 gallons of water it forms a thoroughly efficient destroyer of 

 ticks. 



Later, in the same journal, a dip containing 



Arsenite of soda 5 lb. 



Aloes • . 12 ounces 



Soft soap 5 lb. 



Water 100 gallons 



is recommended. The aloes are morely added to render the 

 dip distasteful, so as to lessen the risk of the animals drink- 

 ing it. This dip contains about 0'3 per cent, of arsenious 

 oxide. 



The soft soap is thought to increase the effect upon the 

 ticks by keeping the wool moist for a longer time after dipping, 

 and for long-wooled sheep it is recommended that the soap' be 

 omitted. 



If the animals are dipped in too strong an arsenical solu- 

 tion, or too frequently, poisoning through absorption of the 

 arsenic by the skin may ensue. This is apparently most likely 

 to occur with long-haired or long-wooled animals. Thus it 

 occurs more i*eadily with sheep than with cattle or horses. It 

 is also said to be more likely to occur if the animals be dipped 

 or sprayed while hot. 



It is unnecessary, perhaps, to emphasise the need of care in 

 using so poisonous a substance as arsenic, but every pre- 

 caution should be taken to prevent animals drinking the dip, 

 or licking or eating anytLii g Avitli wh'ch the arsenical prepara- 

 tion has been in contact. 



Arsenic compounds are also largely used for the destruction 

 of insects injurious to plants or vegetable products. Thu'^ 

 arsenious oxide is now strongly recommended for poisoning 

 white ants. The most successful plan of using it for this 

 purpose is to vapourise a mixture of sulphur and arsenious 



 Mj experience is that commercial arsenite of soda frequently 

 contains about 56 per cent, of arsenious oxide. 



