58 ANNUAL REPORTS OP DEPARTMENT OF AGRICULTURE, lil 
cast- of a i<»t of Infected mosquitoes which were fed on the footpads of the 
healthy guinea pig. The mosquitoes were Infected by feeding on dii 
guinea pigs at the height of the cerebral period and by feeding on a suspen- 
sion of the crushed brains of guinea pigs who died of th< The d 
was transmitted to normal guinea pigs as earl] as 7 'lays and 
days after the Infective meal. This indicates that the mosquitoes, after becom- 
ing infected, may carry the disease as long as they live. 
SAND FLIKS 
Drainage and diking work in controlling Bait-marsh sand dies have been 
continued and extended in Georgia under the partial direction of the Bureau. 
USE OF BLOWFLY MAGGOTS IN THE TREATMENT OF INFE( TED WOUNDS 
The objects of this Investigation have been <i; to devise a satisfactory 
method of producing sterile maggots and of having them available throughout 
the year, so that Surgeons could depend upon their hospital laboratory 
have a continuous supply at all times; (2) to work out. in cooperation with 
surgeons, successful means of applying the maggot treatment to human wounds; 
(.'!> to investigate how maggots produce their remarkable healing eff< 
The first two objectives have now been carried out. and surgeons desiring 
to use maggots should have no difficulty in getting sterile maggots or in know- 
ing how to use them. Work on the third objective shows I hat . in addition 
to removing the diseased tissue, maggots excrete certain suhsiances into the 
wound, and that one of t hose substances, called " allantoin ", stimulates heal- 
ing. This materia] can also he purchased, and during the last 4 months con- 
siderable quantities of it have been used with gratifying effects by doctors 
throughout the Dnited states. Excretions of maggots also contain another 
Substance, not yet identified, which in laboratory tests killed certain difi 
causing bacteria in 5 to 15 minutes without injuring human tissues. 
HOUSEHOLD AND STORED-PRODUCT INSECTS 
Considerable assistance has been given to householders, commercial firms, 
and Federal and local agencies in controlling household and stored-product 
Lnsed pests. Among other studies conducted during the year, the Investigations 
on insects attacking cottonseed meal in storage, the effect of lnsed fumigants 
on paper, and the development of a fumigant for clothes moths are important. 
As a result of the purported decrease in the use of cottonseed meal as a 
fertilizer, larger stocks of tins material were kept in storage during the pas! 
year. These stocks became heavily infested with the cigarette beetle. The 
losses caused by this insect were not so much due to damage to the meal 
itself us to destruction of sacks and the cost of labor Involved in resacklng. 
It was found that fumigating with hydrocyanic acid gas at the rate of 1 pound 
of sodium cyanide to 1,000 cubic feet of storage space. Followed by s s 
treatment l month later, using one-half the amount of cyanide, gave satis- 
factory cent ro|. 
In cooperation with the Bureau of Standards, tests were made to determine 
the effect of fumigants on representative samples of documents which were 
to he placed in the new Federal Archives Building. 
Tests conducted during the year suggest that hydrogenated naphthalene 
(tetrahydronaphthalene) is a promising fumigant against clothes moths. 
Experiments with this material, conducted under conditions which approached 
those actually found in the home. Indicated that it is more effective as a tarni- 
gant against the webbing clothes moth than a mixture containing 75 percent 
of ethylene dichloride and ii."» percent of carbon tetrachloride. 
IDENTIFICATION AND CLASSIFICATION OF INSECTS 
The number of insects received for identification has increased, even i^*^- the 
Qumber submitted in the previous fiscal year. Specialists have devoted 
practically their entire time to the Identification of this material hut have 
been unable to meet the Increasing demands of this service, in the attempt 
to name the specimens submitted for Identification, Investigations started on the 
float ion of several groups of Insects were further restricted ami only 
a few studies of this nature have i>een completed and submitted for publication. 
