EFFECT UPON HEALTH OF MAN 55 



Dr. Dixon, before issuing his statement con- 

 cerning the mosquito-destroying capabilities of 

 ducks, first proved his theory by practical experi- 

 ment. Two ponds, each about 1400 square feet 

 in extent, were selected. In one pond he placed 

 goldfish; the other was reserved for ducks. 

 Within a short time mosquito larvae swarmed in 

 the fish-pond, but none could be found in the pool 

 given over to ducks. Then, to demonstrate the 

 superiority of birds over fish, ten mallards were 

 placed in the fish-pond, and within forty-eight 

 hours the larvae had been eliminated. 



Dr. Dixon has provided a practical demonstra- 

 tion of what ducks are capable of doing. For 

 those of our readers who are desirous of eliminat- 

 ing mosquitos from small bodies of water which 

 exist on their land, this provides a feasible method 

 not difficult to follow. Wood-ducks are among 

 the most beautiful of all birds and easy to pro- 

 cure from licensed wild bird breeders. They are 

 ornamental and highly efficient mosquito destroy- 

 ers. Mallards are almost as bright colored as 

 wood-ducks. They breed well in captivity and 

 and are not difficult to rear. 



3 



Their Effect upon Dikes and Canals 



A minor though highly important function in 

 some localities is the destruction of crawfish by 



