8 



iu leng-tli from north to south. The population to he protected 

 against malaria consists of about 5U,00U labourers and their 

 families and is scattered all over the 500 square miles, though 

 perhaps more concentrated on the line of the Canal and especially 

 in some 40 camps and villages near this line. The local climatic 

 conditions are such that mosquitos will breed freely all the year 

 round and even in the four months in which there is practically 

 no rainfall. The differences in the level of the land through 

 which the ("anal passes do not affect the question, as there is 

 water enough on the high ground for the breeding- of Aiioijheles. 



During the 5 years of the American occupation, 250,000 persons 

 have been broug'ht into the area and the author thinks that the 

 experience (jf Panama may be useful in the military occupation 

 of tropical countries. 



Anti-malarial measures consist of: — (1) destroying the habitat 

 of the Anoplieles during the larval stage within 100 yards of 

 dwellings; (2) destroying- within the same area all protection for 

 llie adult mosquito; (8) screening- all habitations so that 

 mosquitos cannot have access ; (4) where breeding-places cannot 

 be done away with by draining, use is made of crude oil (Phinotas 

 oil aud sulphate of copper) for the destruction of larvae. 



These measures are based u^ion the knowledge that the 

 A/iopli elf's larvae only live as a rule in clear fresh water in which 

 there is a plentiful supply of grass and algae, and that the adult 

 is weak on the wing-, does not fly far, and needs an ample supply 

 of g-rass and brushwood for protection against wind. 



In order to carry out these measures the 500 square miles was 

 divided into 17 districts each under the charg-e of a Sanitary 

 Inspector with the necessary clerks and o assistants, one of whom 

 was ( ompetent as to mosquitos, another as to ditching- and drain- 

 ing, and a third in general executive work. I*iach of the distri(-ts 

 lias an inspector in charge, with 40 or 50 labourers to ditch and 

 drain, carpenters to keep the screening iu repair, and one or two 

 (juinine dispensers, who were kept constantly going round giving 

 8-g-rain doses of quinine to those wlio wished it. !N^o compulsion 

 Avas exercised in this matter. 



The district physician reported daily the number of cases of 

 uudaria to the central ofh(;e which made a weekly report on the 

 whole area, a copy of which was sent to each district inspector 

 who was held responsible for any excess of malaria in his district ; 

 thus, if the rate rose during- the week above 1^ per cent., some- 

 thing was i-onsidered to be wrong aud the assistant to the (Tiief 

 Sanitary Ins])e(-tor was sent to the district to enquire into the 

 cause. 



In ordci' tc (Id away with breeding-jdai-es of larvae tiled drains 

 Mere ])ut down wherever suitable. The author considers this 

 the most effective and economical form of drainage, as on(-e done 

 it requires no furtlier attention, affords no breed ing-plac-e for 

 mosciuitos, and a nuu-hine or scythe can be usetl for cutting the 

 grass over it. Where this plan was not possible, open concreted 

 dit(-hes weie adopted. These are objectionable because they 

 require (-onstant sweeping and cleaning in order to prevent the 

 formation of little puddles of water in which the mosquitos will 

 breed, if neither of these ways ccmld be adopted, then open 



