10 



It will be noted that the above restrictions are liberal enough and 

 at the same time give adequate protection. 



Referring for a moment to the evidence upon which certificates of 

 immunity are based, the writer is of the opinion that a ten years' 

 residence in an endemic focus should no longer be considered suffi- 

 cient, for with our present knowledge of the method of transmission 

 of yellow fever it is quite clear that any intelligent person taking 

 certain simple precautions might very well live a lifetime in an 

 endemic focus and yet never be exposed to infection. 



Measures against the spread of yellow fever. — With reference now 

 to class o — that is, preventive measures against the spread of yellow 

 fever once it has been introduced, we find that as a rule we are not 

 so well equipped. The principle of prophylaxis is, of course, pre- 

 cisely the same, but is much more difficult of application because we 

 have to deal with local and conflicting interests and the ignorance 

 of the people. Municipalities usually have a sufficiency of ordi- 

 nances and regulations covering prophylactic measures against yellow 

 fever, but unfortunately these are completely ignored except when 

 menaced by an epidemic, and then enforced with difficulty. ■ These 

 ordinances have been enacted during a period of stress and excite- 

 ment, when yellow fever was present or dangerously near, and quickly 

 forgotten once the danger had passed. Now, this should not be, for 

 there is no reason why every port in infectible territory should not 

 be so administered as to make it noninf ectible, so that if yellow fever 

 should gain an entrance from abroad its spread would be impossible. 

 To attain this I would outline the following plan : Education and the 

 formation of a public opinion that would look upon the mosquito not 

 only as a disagreeable pest but a very dangerous one as well; proper 

 drainage; a corps of inspectors to, examine all. premises every ten 

 days, preferably once a week, to see that they are free from water 

 containers capable of harboring mosquito larvae; the screening or 

 covering with oil of water containers which can not be destroyed, or 

 the use of small fish where the above methods are not available; 

 the removal of unnecessary vegetation; the screening of dwellings 

 and other buildings. 



In carrying out the above measures there is nothing that requires 

 any great expenditure of money or labor, and if efficiently performed 

 and consistently kept up it would be but a short time before the intro- 

 duction of a case of yellow fever into a locality so governed would be 

 unattended with danger and scarcely cause a ripple of excitement. 



GENEEAL PLAN FOE HANDLING AN EPIDEMIC). 



Where the ideal conditions above mentioned do, not prevail there is, 

 of course, imminent danger of the disease spreading. Steps mus^ be 

 taken at once to prevent this. The bages, ofj preventive, measures, may 



