TERMITES IN THE CANAL, ZONE AND PANAMA. 23 



placed in situ. Wooden forms should be removed after the concrete 

 has hardened; when left, they become infested, and this leads to 

 damage to woodwork, lead cables, etc. Where timber is to be used 

 in contact with the ground, it should be impregnated with coal-tar 

 creosote. The interior woodwork of buildings should also be im- 

 pregnated with chemical wood preservatives; zinc chlorid, bichlorid 

 of mercury, and chlorinated naphthalene 7 will protect wood from 

 attack by termites, unless the situation is very damp, when the 

 soluble chemicals, zinc chlorid and bichlorid of mercury, will leach 

 out (7). 



In the Philippine Islands a termite or " anay " exterminator has 

 been found successful (1, p. 58-59). The method is as follows: To 

 a 5-gallon can of kerosene oil, add 100 cubic centimeters of a 

 saturated mixture of white arsenic in hydrochloric acid (HCL) 

 (about 1 part acid to 1 part water). Tilt can so arsenic solution 

 gathers at one corner. Then add 50 cubic centimeters concentrated 

 sulphuric. acid (H 2 S0 4 ) which will withdraw water from the hydro- 

 chloric acid and will saturate the kerosene with hydrochloric-acid 

 gas containing arsenic trichlorid. This process is dangerous and 

 should be dons out in the open, and the operator must avoid breath- 

 ing the fumes produced. The process is completed after the reac- 

 tion is stopped, and the solution is then ready for use. It is applied 

 by painting or spraying on wood surfaces. Parts not exposed 

 should be exposed and treated; it may also be injected into wood. 

 Since this mixture will corrode the kerosene tin, it should be stored 

 in a glass demijohn. 



No wood known to the writers is immune to attack by termites, 

 but there are many termite-resistant woods, and these should be 

 used wherever possible. The heartwood of teak (Tecton-a grandis) 

 from Siam and Burma; sal (Shorea robusta) of India; cypress pine 

 (CaUitris robusta) of Queensland, Australia; Foochow cedar (Cun- 

 ninghamia sinensis) of China; Eandai cedar (C wining hamia 

 konishii) of Formosa; greenheart (Neotandra> rodioei) of South 

 America; redwood (/Sequoia sempervirens) , incense cedar (Libo- 

 cedrus decurrens), giant arborvitae or western red cedar (Thuja 

 plicata,)* and junipers or red cedars (Juniperus spp.) of the United 

 States are woods which are very resistant to attack by termites, and 

 there are many other such species. 



Oshima (6) states that the resistance of the timbers which he 

 tested to attack by termites is due to the presence of a sesquiterpene 

 alcohol in the wood. 



In the case of the subterranean mound-building termites, in addition 

 to the remedial measures advocated by Dietz and Snyder (£, p. 301), 

 it might be well to experiment with chloropicrin, one of the gases 

 used with success in the World War. Feytaud (3) states that he has 

 used this effectively in France against Reticulitermes lucifugus 

 Rossi infesting the woodwork of buildings. Paradichlorobenzene 

 might also prove effective in killing termites which construct 



7 The chlorinated naphthalene used in these tests is a mixture of various chlorinations 

 as well as free naphthalene, with a large preponderance, however, of tri chlor naphtha- 

 lene. This material is usually referred to as tri chlor naphthalene, and as compared 

 with other chemicals it is really comparable to a technical product having naphthalene, 

 mono chloro naphthalene, di chlor naphthalene, and probably some of the higher chlorina- 

 tions as impurities. Its melting point ranges between 190° and 210° F. This is the 

 specification under which it is sold. 



8 Red cedar poles are badly attacked by Katotermes in California. 



