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 r will protect wood from 
attack by termites, unless the situation is very damp, when the 
soluble chemicals, zinc chlorid and bichlorid of mercurv, will leach 
out (/). 
In the Philippine Islands a termite or ' ; anay " exterminator has 
been found successful (i, 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 done 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 (Tectona grandis) 
from Siam and Burma; sal (Shorea 7'obusta) of India; cypress pine 
(Callitris robusta) of Queensland, Australia; Foochow cedar (Cun- 
ninghamia sinensis) of China; Randai cedar (Ctmninghamia 
konishii) of Formosa ; greenheart (N ectandra 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 {2. p, SOI), 
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 Rettculitermes Vucifugus 
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 chlorinatlons 
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 renily comparable to a technical product, haying naphthalene, 
mono chloro naphthalene, di chlor naphthalene, and prohably some of the higher chlorina- 
tiona 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. 
