Before1900,manytheoriesexistedastothecauseofyellowfever...
問題詳情：Before1900,manytheoriesexistedastothecauseofyellowfever(黃熱病).Somedoctorsweresurethediseasewasair-borne;othersfeltthatitwasspreadfrompersontoperson.Dr.CarlosFinlay,awell-knownCubandoctorofth...