This day relenting God
Hath placed within my hand
A wondrous thing; and God
Be praised. At His command,
Seeking His secret deeds
With tears and toiling breath,
I find thy cunning seeds,
O million-murdering Death.
I know this little thing
A myriad men will save.
O Death, where is thy sting?
Thy victory, O Grave?
Poem he wrote following the discovery that the malaria parasite was carried by the amopheline mosquito.

Memoirs: With a Full Account of the Great Malaria Problem and Its Solution (ed. 1923)