PROGRESS IN BIOLOGICAL INQUIRIES, 1926 621 
little incident that happened a few years ago in a Southern State. I called 
on a State health officer, and while there a reporter came in and said to the 
officer, “Do you have anything for me to-day?” The officer said “ Yes,” and 
gave him the following: “Mr, Hildebrand, of the United States Bureau of 
Fisheries, is here conferring with the State health officer and the sanitary 
engineers as to the best use to make of fish for malaria control.” The evening 
paper printed this item of news with the following headline: ‘ Hat more fish, 
best way to prevent malaria.” 
The use of fish for mosquito control is well established in the South. Of 
course, different situations are met in nearly every locality, and certainly 
they differ among localities. In some of these a very high degree of contro: 
is brought about by the fish alone (seldom 100 per cent control results) ; in 
other environments the degree of control is lower. Intelligence must be exer- 
cised in the use of fish for mosquito control, just as in using drainage, oil, or 
Paris green for controlling mosquito breeding. 
I was asked several years ago by a Kiwanis Club in a southern city to talk 
to them on the use of fish for mosquito control. During my talk I made the 
statement that top minnows first were used for this purpose on a large scale 
in 191S—that is, during the war. My statement was challenged by an engineer 
present, who informed us that his company used the fish on a very large scale 
as early as 1918. I was obliged to admit that I knew nothing of this early 
work. However, I made diligent inquiry later, and I learned that this power 
company had received, presumably through the Bureau of Entomology, half a 
dozen cans of Gambusia from Louisiana to plant in an artificial lake almost 
on the Atlantic border, which had an area of several thousand acres. The 
fish certainly were given a wide range and a very large scale of work to do, 
but that obviously was not what I meant, nor was that intelligent employment. 
Several Southern States now have regulations requiring the establishment 
of ponds on or near the area to be flooded for the purpose of propagating 
Gambusia, not by the hundred or even thousands, but by the millions. Such 
a regulation is not difficult to enforce, for the power companies have suf- 
fered such heavy losses from damage suits brought by people living in the 
vicinity of newly flooded areas, who have claimed damages because they 
suffered greatly from malaria. Consequently, the companies have learned their 
lesson and they are most anxious to do what they can to prevent malaria. The 
propagation of the minnows, particularly under artificial feeding, even in 
new ponds, has been very successful, and the results derived by way of 
mosquito control have been good. Of course, other methods of control, too, 
have to be used frequently in newly impounded waters. The little fish, if 
plentiful enough, will destroy the wiggle-tails if they can get them. Frequently, 
however, floating débris is so thick and so abundant in newly flooded areas 
that aid must be given. . 
Recently, upon the suggestion of a United States Public Health Service 
officer, I addressed a series of letters to 14 State health officers who are doing 
mosquito-control work for the purpose of controlling malaria, making inquiry 
relative to the use of fish (Gambusia) for malaria control. One State replied 
that the fish had been tried and found entirely unreliable and their use no 
longer was recommended. Another replied that other methods of control so 
far had appeared preferable for the very limited amount of work done in that 
State. However, plans were being made to use the fish in new work planned 
for next season. The other 12 all replied that they considered the fish very 
useful and depended upon them a great deal. 
Sufficient investigations have been made in the South to have determined 
that Gambusia is the one fish to rely upon, as it is a natural mosquito eater. 
We are less fortunate, however, in the North. I wish to bring to your atten- 
tion the crying need for further investigations of this problem in the northern 
waters, where Gambusia does not occur naturally. Prof. J. Percy Moore made 
a good beginning when he studied this problem briefly in the vicinity of Phila- 
delphia and New York City. However, the study should be carried on much 
further; it should be done more thoroughly and it should be carried to other 
localities. The need for such a study has been impressed upon me very strongly 
during the past fall, when a great many inquiries relative to the use of fish 
for mosquito control were referred to me by various public health officials as 
well as private citizens. Of course, under the circumstances definite recom- 
mendations are impossible. 
We have been telling these people that Gambusia could not be used. Now I 
learn that this fish has lived and multiplied for several years in certain ponds 
