MISCELLANEOUS 229 



undissolved, as this makes it less likely that there is excess of 

 lime in the liquid. 



Of course, in preparing 100 gallons of the dip the lime 

 should be treated with only about 5 to 10 gallons of water, 

 heated to boiling, the sulphur added in fine powder little by 

 little, and the whole boiled for about two hours, or until most 

 of the sulphur has disappeared. The strong solution of calcium 

 sulphides and thiosulphate is then diluted to 100 gallons with 

 water. 



The dip should be used as soon after preparation as possible, 

 as it absorbs carbon dioxide and oxygen from the air and the 

 calcium sulphide and pentasulphide are decomposed. Many 

 users have obtained better results by using the dip at a tem- 

 perature of about 100° to 110° F. (38° to 43° C). Each animal 

 should remain at least two minutes in the dip. 



Hellebore ( Ve^'atrum alburn). — The root of this plant contains 

 several alkaloids, of which veratrine, CggH^gNOg, protoveratrine 

 CgjHjjNOu, and jervine, CggHj^NOg, are poisonous to animals. 

 It is occasionally used as an insecticide, either in the dry, 

 finely powdered state, often mixed with flour, or in water — 

 about an ounce to 3 gallons of water. It is efficacious against 

 leaf -gnawing insects, and is not so poisonous to animals or man 

 as the arsenites. 



Lisect-powder is the finely powdered flower-heads of a plant 

 Two species of plant are used — Pyrethrum roseum, the pro- 

 duct from which is known as Persian or Caucasian insect- 

 powder, and Pyrethrum citieraricefoliumj which yields Dal- 

 matian insect-powder, or '' buhach," as it is called in California. 

 The Dalmatian product is said to be more effective than the 

 Persian. It can be used dry, often mixed with three times it.i 

 weight of flour, or in aqueous or alcoholic solution, also in 

 fumigation. The substance can be used to destroy aphides, 

 house insects of various kinds, and, especially by fumigation, 

 for driving away mosquitoes and flies. For spraying solution 

 1 ounce of the powder is mixed with 2 or 3 gallons of water. 

 A little alcohol is sometimes first added to the powder, and the 



