164 
AN EXPERIMENT IN FUMIGATION OF TICKS. 
By C. W. HOWARD. 
Chief of the Entomological Section, Department of Agriculture, 
Lourengo Marques, Mozambique. 
So far as I have been able to find, very little work, if any, has been 
done to ascertain the resistance of ticks to the gases usually employed 
in fumigation. This is probably because fumigation for the destruction 
of ticks is not, under oi’dinary conditions, a practical method. There 
recently arose, however, a question at Lourenyo Marques (Portuguese 
East Africa), as to whether ships bringing cattle from Madagascar could 
be cleaned of the ticks which might have dropped from the cattle and 
be thus rendered clean for use in the transport of clean cattle for 
breeding purposes. The port authorities possessed a “Clayton Fumi¬ 
gating Apparatus ” for use in disinfecting plague-infected ships and 
it was suggested that this system be tried for the purpose. Several 
tests were accordingly carried out with the co-operation of the Chief 
of the Veterinary Service, the Port Doctor, Municipal Officer of Health, 
and several local medical men. The “ Clayton ” being a standard 
system of fumigation, I will not enter into a discussion of it. 
The management of the Clayton machine was left to the Port 
Doctor while the arrangement of the tests as regarded the ticks was 
in the charge of the writer. The ticks were arranged in several ways 
which we considered to approximate to the conditions under which 
ticks would be when they had fallen from cattle and crawled under 
debris and into cracks and crevices in the hold of a ship. Some of the 
tests were made as severe as possible and were severer than would 
ordinarily be met. 
The first test was made on January 9th, but owing to a misunder¬ 
standing the hold of the ship where the test was made was not exposed 
to the gas for a sufficient length of time. Plague-infected ships are, 
I believe, exposed to the gas for six hours, counting from the time 
