102 PREVENTIVE AND REMEDIAL WORK AGAINST MOSQUITOES. 



WORK IN JAPAN. 



Work in Japan as early as 1901, under Surgeon Major Tsuzuki, con- 

 firmed experimentally the malarial relations of Anopheles, and later 

 a large-scale experiment was carried on among the Japanese troops 

 occupying Formosa, which, on account of its extent, served to set at 

 rest any doubts which had previously existed as to the value of mos- 

 quito protection. Portions of Formosa are malarious, and the 

 following table indicates the conditions existing among these troops 

 from 1897 to 1900: 





Number of 

 patients. 



Number of 

 deaths. 



Ratio of 

 patients. 



Ratio of 

 deaths. 



1897 



41,825 

 34,752 

 29,371 

 30. 224 



267 

 270 

 284 

 272 



Per cent. 

 272. 435 

 249. 394 

 221. 263 

 222. 414 



Per cent. 

 1.739 



1898 



1.938 



1899 



2.139 



1900 



2.002 







On the 21st of September, 1901, and extending through to the 

 28th of February, 1902, work was carried on by order of the governor 

 of Formosa, on the advice of Doctor Koike, surgeon-general, as 

 follows. This account of the experiment is taken from an address 

 by Dr. K. Tamura, delegate from Japan to the Eleventh Annual 

 Meeting of the Military Surgeons of the United States Army, June 

 7, 1902: 



Half of the second company, first battalion of infantry at Kirun, Formosa, 115 in 

 number, was employed from the day of their landing at Kirun, and we gave it the 

 name of "protected troops." This troop was thoroughly provided with means of 

 protection from mosquito bites. They were confined in the casern from half an hour 

 before sunset to half an hour after sunrise, the casern having been specially made to 

 prevent mosquitoes entering, and they wore gloves and coverings of the head specially 

 made for that purpose when on service at night. 



The results of these new methods for the prevention of malaria were absolutely 

 good. Another half of the second company (called by us "comparison troop") and 

 all the other companies of the battalion (called by us "unprotected troop") had a 

 great many malaria patients, but the protected troop had none. 



The table of the number of patients is as follows: 



Average 

 number 

 of men. 



Number of 

 patients. 



Ratio of 

 patients. 



Protected troop... 

 Comparison troop. 

 Unprotected troop 



114.49 

 104. 34 

 646.36 





 34 



285 



Per cent. 

 

 32.59 

 44.09 



The experiment of Grassi in Italy shows that 5 cases of malaria were observed 

 among 112 persons, and Celli observed 11 cases in 203 persons, but our case shows 

 none in 114 persons. 



