87() INSEC'TU'IDKS, 11 NC.ICIDES, AM> \\\A:l) KILLKKS. 



on the one hand, 5 U). of quassia chips in oO gallons of water ; let stand 

 for twenty-four hours and decant the extract; on the other hand, dis- 

 solve o Ih. of soft soap in 50 gallons of water. Mix the two liquids. 

 (2) 7.1 Ih. of quassia are macerated and 3^ lb. of soap are dissolved 

 in 100 gallons of alcohol (Alvood). (3) 1^ lb. of quassia are naacerated 

 in water, heated to boiling and decanted ; after twenty- four hours a solu- 

 tion of 2i} lb. of soft soap is added and the bulk made up to 10 gallons 

 (Klein). (4) Dissolve 10 lb. of soft soap in 5 gallons of hot water, 

 add thereto an infusion of 2^ lb. of quassia chips obtained b}- twelve 

 hours' steeping in 5 gallons of rain water ; make up to 40 gallons 

 (Koch's insecticide). (5) Emulsify 5 gallons of petroleum in a solution 

 of 6 lb. of soft soap in 50 gallons of water (see petroleum), and add 

 thereto an extract of 10 lb. of quassia in 50 gallons of water. (6) Add 

 4 lb. of carbolic acid to a mixture of 5 lb. of quassia extract and 6 lb. 

 of soa}) in 100 gallons of Vv^ater (Gilardi). 



Properties. — Quassine, the active principle of quassia amara, is 

 amorphous or crystalline. It has been isolated by Winkler. It is 

 colourless, inodorous, opaque, and inalterable in the air, slightly soluble 

 in water, mucli more soluble in water charged with salt or organic 

 acids, and in alcohol. To man, quassine is not poisonous, it is toxic, 

 aperient, and stomachic. In doses of 4-10 centigrammes per day, 

 quassine has no injurious effects on man ; on the other hand, it is 

 deadly to the lower animals — oxyures, ascarides, etc. 



Action on Plants. — Plants are not injured by spraying with 

 aqueous extracts of quassia ; on the other hand, extracts mixed Wiih 

 soap are injm-ious to certain plants, especially if soft soap be used and 

 if the dose is superior to 1 per cent. Fleischer prepai-ed the following 

 table on this point for Klein's solution (No. 3 supra) : — 



TABLE LXXKIII. — SJiowing tlic Action of Klein's Siiliition (3) on tlie Organs 

 of y'nrioiis Plants. 



Plants and their Organs. Action. 



Shoots and leaves of the apple-tre? .... Hardly attacked 



Leaves of the plniii ,, ,, 



Vine .......... I'naltacked 



Nastuitium (ji-catly damaged 



Action on Insects. — No insect can live in boxes made of quassia 

 wood (Wright) ; fly-paper is blotting-paper soaked with a sugared extract 

 of quassia. Quassia insecticides act on soft-skinned, non-protected 

 insects, on their larvae, on caterpillars, plant lice, and phytotides. 

 Koebele regards quassia extracts as less active than fish-oil emulsions. 



Use. — CaterjnUars of Fruit Trees. — ^ Insecticide (5) is recom- 

 mended by Gilardi as an excellent medium for destroying various 

 caterpillars which infest fruit trees. 



Conchjjlis aiiibl(jitella, Hui)n. (cochylis of the vine).- — -Insecticide 

 No. 1 is regarded by Gilardi as sufficient to destroy the caterpillar of 

 the cochylis. 



Unprotected Plant Lice. — Plant lice are very sensitive to quassia 

 extracts. Whitehead I'ecommends insecticide No. 1 against the hop 

 aphis and the wheat aphis ; Klein and Fleischer insecticide No. 3 



