113 



"INSECTS AND DISEASE." 



By J. S. C Elkinqton, m.d., d.p.h , 

 Chief Health Officer of Tasmania, 



(Read 9th May, 1904.) 



Dr. Elkington said : — The subject upon 

 which I have been asked to address you 

 this evening is one which has, witbin the 

 past six years, produced a profound alter- 

 ation in several branches of science. 

 Here in Tasmania we are fortunately free 

 from those scourges of humanity which 

 are as yet known to depend wholly for their 

 spread upon the agency of insect life, but 

 even with us the problem is not wholly 

 one of outside interest, as I will endeavor 

 to show you in relation to typhoid fever. 

 In this case, however, the method of con- 

 veyance is purely a mechanical one, due 

 to particles of infected matter clinging to 

 the legs and bodies of flies, and subse- 

 quently deposited upon food material, 

 whence it is taken into the alimentary 

 canal of the victim. It is advisable, 

 therefore, to clearly distinguish between 

 the two methods in which insects play a 

 part in spreading disease amongst human 

 beings, whether — 



(a) As carrying agents pure and simple, 

 the infecting agent undergoing no change 

 and not being dependent on the insect in 

 any way. 



(b) As hosts, intermediate or definitive, 

 the infective organism being dependent 

 upon the insect and undergoing an extra- 

 corporeal phase of development in its 

 tissues. 



The first group is of distinct import 

 ance from the sanitarian's point of view, 

 in that it teaches us to guard against 

 a real danger in times of prevalence 



of certain infectious diseases, but the 

 second one far outweighs it. Into this 

 second group fall some of the chief 

 scourges of mankind, in tropical regions 

 at any rate, and of these the greatest is 

 malaria. Next to tuberculosis, malaria is 

 probably the greatest cause of death and 

 of ill-health with which mankind has to 

 contend. Some of you have, no doubt, 

 visited or lived in places where malaria, 

 or even Yellow fever, have claimed iheir 

 yearly toll of lives and health, have seen 

 the long white-washed wards and wide 

 verandahs of an Indian Cantonment 

 Hospital filled with pasty-faced fever- 

 stricken soldiers, and have heard day after 

 day the drone of the regimental bands 

 along the dusty white roads to the ceme- 

 tery. To that supreme critic of all our 

 actions, the "man in the street," the proof 

 of the conveyance of malaria by the agency 

 of certain species of mosquitoes was 

 merely an interesting piece of knowledge, 

 but to those who know what the disease 

 in question really means, it was a fact of 

 startling importance, presaging the ap- 

 proach of effective means of checking an 

 enemy which in the year 1897 alone laid 

 75,821 British soldiers by the heels in 

 hospital out of a total strength of 178,000 

 odd in all India. I need hardly remind 

 you how nobly the promise of that great 

 discovery has been fulfilled, how " the 

 white man's grave " of former years has 

 become the white man s sanatorium, and 

 how it is now possible for the march of 



