Amateurs are fond of advising that all practical measures should be postponed pending carrying out detailed researches upon the habits of anophelines, the parasite rate of localities, the effect of minor works, and so on. In my opinion, this is a fundamental mistake. It implies the sacrifice of life and health on a large scale while researches which may have little real value and which may be continued indefinitely are being attempted… In practical life we observe that the best practical discoveries are obtained during the execution of practical work and that long academic discussions are apt to lead to nothing but academic profit. Action and investigation together do more than either of these alone.

The case which I reported on September 26, 1901, was really the last which occurred in Havana. Of course we did not know it at the time, but this case marked the first conquest of yellow fever in an endemic center; the first application of the mosquito theory to practical sanitary work in any disease.