414 THE INSECT WORLD. 
We are indebted to M. de Quatrefages for some interesting 
experiments on the termites of La Rochelle. Not only has the 
learned naturalist helped to make known to us the habits of these 
dark-loving insects, but he has also told us how to destroy them. 
Different substances have been tried in vain to stop these terrible 
ravages—essence of turpentine, arsenical soap, boiling lye, &e. 
M. de Quatrefages had recourse to gaseous injections. He tried 
successively binoxide of nitrogen, nitric acid, chlorine and sul- 
phurous acid; chlorine, above all, fully answered his hopes. With 
pure chlorine, he killed the termites instantaneously ; mixed with 
nine-tenths of air, he suffocated them in half an hour. ‘“ For 
attacking the termites,’ says M. de Quatrefages, “one ought to 
choose by preference the period of their reproduction, so as to 
destroy the pregnant females. It is probable that, like their 
exotic congeners, the termites of France will endeavour to defend 
themselves by walling up the interior of their galleries at the 
first signs of an attack. The operator must then act with a great 
deal of promptitude, and direct the apparatus as much as possible 
into the very centre of their habitation, where the galleries are 
the broadest and the most numerous. 
“With whatever care one acts, and whatever may be the suc- 
cess of a first attempt, it seems to me impossible to destroy in 
one campaign all the termites of a locality. In this, as im all 
operations of the same kind, a certain amount of perseverance is 
necessary, especially if it is in a town or in a country infested by 
them to a very great degree; in that case, one will be forced to 
repeat the operation from time to time. When, on the contrary, 
the termites are already cantoned, it seems to me that the success 
ought to be lasting. This is fortunately the case at La Rochelle; 
and by knowing how to profit by it, one may doubtless prevent 
the spread of these pests, which, at one time or another, may 
attack the whole town.’’* 
In 1864 the Lords of the English Admiralty addressed an in- 
quiry to the Entomological Society of London, on the best means 
of preserving wood from the attacks of the Indian termites. In 
answer to this inquiry, the Entomological Society recommended 
* “Mémoires sur la destruction des Termites.” Annales des Sciences Naturelles, 
de serie, tome xx., p. 15. 
