82 



siderably larger now than at that time, I think this indication very 

 favourable. I think it also indicates that the measures recently 

 inaugurated, with regard to killing mosquitoes in and about the 

 infected area, are having good results. 



****** 



The amount of sanitary work continues large. We are not now 

 doing as much cleaning of houses with our own force as formerly ; I 

 have transferred about two-thirds of these men to the mosquito 

 brigades. They are employed in cleaning out the various ditches 

 and streams where stagnant water is found, a'nd putting kerosene oil 

 in all of these places. During the month about 20,000 houses have 

 been gone over in this manner. A little oil is placed in every recep- 

 tacle containing standing water and about an ounce into every 

 closet and sink in the houses having water connections. Nearly every 

 house in Havana has a cess-pool, and these cess-pools are ideal 

 breeding-places for mosquitoes. The oil in this way runs into the 

 cess-pool and kills the larvae. I have recently examined several of 

 the main sewers that empty into the bay, and have seen a large num- 

 ber of larvae floating out, showing that a considerable number are 

 being killed by this method. 



May, 1901. 



****** 



But what I think most important to us is, the unusually favourable 

 showing made by the city this year, as to yellow fever. We com- 

 mence June with the city free from yellow fever, no cases being on 

 hand. This is probably the first time Havana has ever entered June 

 free from yellow fever. April and May also commenced in the same 



way. 



****** 



I cannot but hope that this exceptionally good condition is in great 

 part due to the large amount of labour and money we are expending, 

 in the destruction of mosquitoes ; and the circumstances of the case 

 point in the same direction. 



Since March 8th, outbreaks of yellow fever have occurred twice. 

 The first time, April 2ist and 22nd, we had two cases ; and again on 

 May 6th and 7th, four cases. Each time the infected houses and 

 three or four contiguous houses, on every side of the infected house, 

 were carefully gone over. Every room in each of these houses was 

 closed and sealed, and insect powder burned in them at the rate of I 

 pound to 1,000 cubic feet. All standing water was drained away, 



