370 Philippine Journal of Science i^ 19 



TEST OF THE RESISTANCE OF CAMPHOR GREEN OIL TO TERMITE ATTACK 



As supposed in the beginning, camphor green oil really con- 

 tains sesquiterpene alcohol, which is said to be effective in 

 preventing the attack of termites. In order to prove its effect 

 practically, the following tests were carried on: 



Experiment 1. — Camphor green oil, roughly fractionated in 

 the Monopoly Bureau, was injected into Japanese pine by means 

 of full process. The blocks (2 by 2 by 15 inches, or about 

 5 by 5 by 38 centimeters) were buried in ground infested by 

 Coptotermes formosanus with several control pieces (untreated 

 pine) . The controls were seriously attacked within five to seven 

 days (Plate XI, fig. 2, a, b), while the treated blocks remained 

 unattacked for about one year (Plate XI, fig. 2, c). 



It is obvious that camphor green oil is effective in preventing 

 the attack of termites. However, it is very expensive, if the pure 

 oil is used. As shown in Table XXVI, the amount of oil produced 

 in the Monopoly Bureau is not sufficient for treating all the 

 timbers used in Formosa. 



Table XXVI. — Camphor green oil produced by the Monopoly Bureau, 



Year. Pounds. 



1912 44,562 



1913 23,491 



1914 28,397 



Containing only 1.04 per cent of volatile oil, cypress pine 

 is highly resistant to termites. Foochow cedar, more or less 

 resistant to termites, contains 4.6 per cent of volatile oil. It 

 seems reasonable to expect, therefore, that a small amount of the 

 camphor green oil may be effective in preventing damage. If 

 this is true, we can economize the green oil by using a small 

 amount, instead of a large quantity as in the case of creosoting 

 (5 to 6 gallons per cubic foot, or 18 to 22 liters per 0.028+ 

 cubic meter, of timber) . 



To use the camphor green oil practically, it is necessary to 

 employ a method of treating timbers at the lowest expense, 

 injecting only a small amount of the oil. In order to determine 

 the limit of the amount of oil that is effective in preventing 

 damage, the following experiment was made: 



Experiment 2. — Camphor green oil was dissolved in 90 per 

 cent ethyl alcohol, making 1, 2, 3, 5, and 10 per cent solutions. 

 After injecting each solution into Japanese pine (2 by 2 by 15 

 inches, or about 5 by 5 by 38 centimeters), the alcohol was 



