WEBVTT 00:00:04.490 --> 00:00:24.470 [National Library of Medicine. HF 1529. This transfer made: 11/07/05 Length: 00:15:30] 00:00:24.470 --> 00:00:33.660 [United States Navy Training Film. Restricted] 00:00:33.660 --> 00:00:39.880 [DDT] 00:00:39.880 --> 00:00:41.800 Because we're fighting a total war, 00:00:41.800 --> 00:00:45.580 our forces must be marshaled against every enemy, 00:00:45.580 --> 00:00:47.770 unseen, as well as seen, 00:00:47.770 --> 00:00:50.760 in every place, all of the time. 00:00:50.760 --> 00:00:54.580 Millions of insects constitute an important part of our foes, 00:00:54.580 --> 00:00:57.700 in their way, as militant as the Axis. 00:00:57.700 --> 00:01:01.130 Their menace multiplies as they multiply. 00:01:01.130 --> 00:01:09.310 Because in some areas more men were being incapacitated from action by insect-born diseases than by battle casualties, 00:01:09.310 --> 00:01:14.900 a search for a more powerful insecticide than had previously been known was imperative. 00:01:14.900 --> 00:01:18.460 The answer to the quest for a poison to eradicate the insects 00:01:18.460 --> 00:01:26.700 which threatened the morale, health, and military efficiency of our troops was found in DDT. 00:01:26.700 --> 00:01:30.600 By intensive research, the nation's leading insecticide experts 00:01:30.600 --> 00:01:36.180 have determined the forms of DDT best suited to the needs of the armed forces. 00:01:36.180 --> 00:01:41.420 To this government laboratory, potential insecticides are submitted for evaluation. 00:01:41.420 --> 00:01:48.670 When the first sample of DDT was submitted in November 1942, it underwent routine tests. 00:01:48.670 --> 00:01:57.920 First synthesized by a German chemist in 1874, DDT had not been recognized as an insecticide until 1939, 00:01:57.920 --> 00:02:02.690 when a Swiss chemical firm began to use it against moths and plant lice. 00:02:02.690 --> 00:02:07.890 It arrived unheralded, but inherent was the power to curb epidemics. 00:02:07.890 --> 00:02:11.180 For almost two years after its arrival in the United States, 00:02:11.180 --> 00:02:16.110 DDT was available only in quantities sufficient for experimentation. 00:02:16.110 --> 00:02:24.230 During this period, a formula for DDT emulsion concentrate, that golden liquid in the flask, was developed. 00:02:24.230 --> 00:02:30.630 It was found that the ideal dilution is one part emulsion concentrate to four parts water. 00:02:30.630 --> 00:02:34.490 This produces a 5 percent DDT emulsion. 00:02:34.490 --> 00:02:39.240 When thoroughly mixed, the DDT hangs in suspension. 00:02:39.240 --> 00:02:45.710 If this mixture is sprayed, the DDT makes a residual deposit. 00:02:45.710 --> 00:02:57.910 It was also found that when the mixture stands for 24 to 48 hours, a creamy layer rises to the surface, indicating a breaking of the emulsion. 00:02:57.910 --> 00:03:05.290 Yet, stirring returns it to its former constituency, and it regains its original effectiveness. 00:03:05.290 --> 00:03:09.840 In comparing the relative effectiveness of DDT and fuel oils, 00:03:09.840 --> 00:03:21.870 it was found that one half pint of 25 percent DDT emulsion concentrate is equivalent in insecticidal power to one gallon of 2 and one half percent DDT solution. 00:03:21.870 --> 00:03:28.230 In either form, it is adequate to destroy mosquito larvae over an area of 1 acre. 00:03:28.230 --> 00:03:35.390 Earlier larvaciding, without DDT, required 3 five-gallon jars of diesel oil per acre. 00:03:35.390 --> 00:03:44.670 To repeat: one half pint of DDT emulsion concentrate, or one gallon of two and one half percent DDT solution, 00:03:44.670 --> 00:03:50.070 is equal in larvaciding power to 15 gallons of diesel oil. 00:03:50.070 --> 00:03:56.170 Tests were also made to determine the physiologic effect of DDT upon insects. 00:03:56.170 --> 00:03:59.070 Absorbed through the feet or other parts of the body, 00:03:59.070 --> 00:04:04.440 DDT affects the nervous system and motor coordination of the insect. 00:04:04.440 --> 00:04:07.860 Several hours elapse before symptoms develop. 00:04:07.860 --> 00:04:15.620 Then, in sequence follow restlessness, tremors, convulsions, paralysis, and death. 00:04:15.620 --> 00:04:20.000 Flies and mosquitoes react most quickly to this insecticide. 00:04:20.000 --> 00:04:24.510 Death comes more slowly to bedbugs and roaches. 00:04:24.510 --> 00:04:29.320 Complete annihilation of mosquito larvae requires 24 hours. 00:04:29.320 --> 00:04:35.880 Under the influence of DDT, they become paralyzed, and are unable to return to the water's surface. 00:04:35.880 --> 00:04:39.040 After a few hours, death ensues for all. 00:04:39.040 --> 00:04:45.180 The sample in the center so closely resembles corn starch on the left, and flour on the right, 00:04:45.180 --> 00:04:49.900 that obviously, this insecticide should not be stored in galleys. 00:04:49.900 --> 00:04:55.600 Because oil solutions penetrate the skin, carelessness in handling them is dangerous. 00:04:55.600 --> 00:05:02.810 If knapsack type equipment must be used, it should be only half filled to avoid spillage. 00:05:02.810 --> 00:05:09.030 Occasional contact is not harmful; repeated contact must be avoided. 00:05:09.030 --> 00:05:16.790 One of the forms in which DDT is supplied in the Navy is the 100 percent powder for the preparation of oil solutions. 00:05:16.790 --> 00:05:22.320 When exposed to atmosphere and sunlight, it does not evaporate nor deteriorate. 00:05:22.320 --> 00:05:31.250 Unless all lumps are broken apart, a jelly-like coat, which defies solution, forms about them when they are mixed with oil. 00:05:31.250 --> 00:05:35.510 Contact of the hands upon the dry powder is not dangerous, 00:05:35.510 --> 00:05:40.390 for in this form, DDT is not absorbed through the skin. 00:05:40.390 --> 00:05:49.180 The physical properties of DDT are such that it may be dispersed in emulsions, in oil solutions, or in dust solutions. 00:05:49.180 --> 00:05:52.280 Oil solutions are probably the most useful form. 00:05:52.280 --> 00:06:01.290 Diesel oil number two, as a solvent, gives excellent results, for it has a viscosity well-suited to the sprayers now in use. 00:06:01.290 --> 00:06:07.190 The powder is thoroughly suspended in a small quantity of oil before it is added to the bulk in the drum. 00:06:07.190 --> 00:06:13.670 Saturated fuel oils contain about 9 percent DDT. 00:06:13.670 --> 00:06:17.680 Crude kerosene dissolves about 7 percent; 00:06:17.680 --> 00:06:22.540 refined kerosene, less than 4 percent. 00:06:22.540 --> 00:06:30.410 In mixing oil solutions, a special care against contact with the skin should be exercised, for the oil penetrates the skin. 00:06:30.410 --> 00:06:33.780 Large doses of DDT lead to nerve and liver damage. 00:06:33.780 --> 00:06:40.620 DDT goes into solution in oils rather slowly, requiring 12 to 24 hours. 00:06:40.620 --> 00:06:45.780 The warmth of the sun, and hourly stirring, by rolling, hasten the process. 00:06:45.780 --> 00:06:52.840 DDT does not deteriorate under temperatures encountered in ordinary storage aboard ship or in the tropics. 00:06:52.840 --> 00:07:03.570 When a dry mix is desired, the 10 percent DDT powder is diluted with fine road dust, condemned flour, lime, or soap stone. 00:07:03.570 --> 00:07:11.250 One hundred percent DDT occurs in particles too large and hard to be broken up without heavy grinding equipment. 00:07:11.250 --> 00:07:16.550 Hence, it cannot be diluted in the field for use as a dust. 00:07:16.550 --> 00:07:21.180 Thorough mechanical mixing is required. 00:07:21.180 --> 00:07:24.490 The strength of the mixture is determined by its intended use. 00:07:24.490 --> 00:07:31.030 It would be difficult to scatter 1 pound of 10 percent dust evenly over 1 acre. 00:07:31.030 --> 00:07:36.710 But 10 pounds of 1 percent dust may easily be spread over the same area. 00:07:36.710 --> 00:07:41.140 Now let's consider the ways to disperse DDT. 00:07:41.140 --> 00:07:45.200 Equipped with a supply of oil solution and power spraying equipment, 00:07:45.200 --> 00:07:50.640 a malaria control squad enters an abandoned village, a reservoir of infection. 00:07:50.640 --> 00:07:59.340 Within 24 hours, the vectors of typhus, yellow fever, malaria, dengue, filariasis, and dysentery begin to disappear. 00:07:59.340 --> 00:08:02.040 DDT is not a repellent, however. 00:08:02.040 --> 00:08:07.590 It kills - surely, but slowly. 00:08:07.590 --> 00:08:11.280 Hence, its effectiveness cannot be measured by a count of dead insects, 00:08:11.280 --> 00:08:16.360 for after receiving a lethal dose, the insects go elsewhere to die. 00:08:16.360 --> 00:08:25.040 Residual treatment of the inner walls of these huts means that a contact poison awaits any insect which alights upon them for several weeks or months, 00:08:25.040 --> 00:08:34.000 depending on variant factors, such as the intensity of the original treatment, rains, washing, prevailing winds, and so forth. 00:08:34.000 --> 00:08:40.820 Using a paint sprayer, the worker spreads DDT evenly so that the entire surface is covered. 00:08:40.820 --> 00:08:44.840 A semi-coarse spray is required for residual treatment. 00:08:44.840 --> 00:08:47.710 A fine spray is lost in the air. 00:08:47.710 --> 00:08:51.430 Experience teaches the correct amount to spray without waste. 00:08:51.430 --> 00:08:59.490 The entire surface should be thoroughly wet, without runoff. 00:08:59.490 --> 00:09:04.830 Residual treatment of all quarters pays big dividends in the health and happiness of the crew. 00:09:04.830 --> 00:09:11.050 In a few hours, a two-man crew may treat hundreds of mattresses and bunks with 5 percent DDT and kerosene. 00:09:11.050 --> 00:09:17.300 If correctly applied, this renders sleeping quarters free from bedbugs for many months. 00:09:17.300 --> 00:09:21.250 Mattresses should not be slept on until the kerosene has evaporated, 00:09:21.250 --> 00:09:24.790 and the smoking lamp should be out until the following morning. 00:09:24.790 --> 00:09:29.580 Because DDT crystals cling tenaciously to the fibers of textiles, 00:09:29.580 --> 00:09:35.400 cots, tents, and jungle hammocks should receive the residual treatment. 00:09:35.400 --> 00:09:43.150 By treating bed frames and springs in this position, salvos are simultaneously fired against the bedbugs in the walls. 00:09:43.150 --> 00:09:46.970 This increases efficiency, and eliminates waste. 00:09:46.970 --> 00:09:49.150 Before treating galleys and mess halls, 00:09:49.150 --> 00:09:53.640 food, trays, cooking utensils, and work tables must be covered. 00:09:53.640 --> 00:10:00.510 Kerosene is used as a solvent for residual spraying of areas where stains from darker oils are to be avoided. 00:10:00.510 --> 00:10:11.970 For residual treatment against roaches, 5 percent DDT in kerosene, fuel oil, or emulsion, is sprayed around pipes, in cracks, and in other places they frequent. 00:10:11.970 --> 00:10:15.500 It is as effective as 10 percent DDT dust. 00:10:15.500 --> 00:10:22.170 DDT crystals in the interstices of screens poisons insects where they frequently alight. 00:10:22.170 --> 00:10:25.830 Here, DDT emulsion is applied with paint brushes. 00:10:25.830 --> 00:10:31.250 When the emulsion has dried, the screen has almost regained its former appearance. 00:10:31.250 --> 00:10:36.950 An alternative method for treating screens is with an ordinary spray gun. 00:10:36.950 --> 00:10:41.240 The insecticide is more apt to be wasted this way, however. 00:10:41.240 --> 00:10:46.580 DDT oil solution leaves an effective residuum on garbage racks and other fly habitats. 00:10:46.580 --> 00:10:52.690 Since these surfaces are frequently washed, repeated applications become necessary. 00:10:52.690 --> 00:10:57.560 Because dysentery is second only to malaria as a threat to military operations, 00:10:57.560 --> 00:11:02.520 it is especially important to treat the slit trench and surrounding areas. 00:11:02.520 --> 00:11:07.790 Garbage pits, dugouts, and gun emplacements should be similarly sprayed. 00:11:07.790 --> 00:11:15.370 Unless the entire bivouac area is treated, an influx of insects from adjacent areas may occur. 00:11:15.370 --> 00:11:24.550 Bushes, logs, dead leaves, and the ground itself should be sprayed. 00:11:24.550 --> 00:11:31.510 Residual treatment upon the inside of planes prevents the spread of disease vectors to uninfested islands. 00:11:31.510 --> 00:11:38.340 This supplements, rather than replaces, the use of aerosol bombs in aircraft. 00:11:38.340 --> 00:11:42.890 Either pressure or hand sprayers may be used. 00:11:42.890 --> 00:11:50.090 For killing insects on the wing, a fine fog spray, wind drifted, has been found most effective. 00:11:50.090 --> 00:11:54.150 Repeated fog applications may even leave a residuum. 00:11:54.150 --> 00:12:03.610 Men with DDT aerosol bombs, walking briskly 20 feet apart, eradicate insects on the wing within the area traversed. 00:12:03.610 --> 00:12:07.730 Excessive winds reduce the effectiveness of this treatment. 00:12:07.730 --> 00:12:15.320 By the addition of DDT to Navy aerosol bombs, greater effectiveness against mosquitoes has been attained. 00:12:15.320 --> 00:12:21.290 Flies, which previously defied this treatment, are now killed. 00:12:21.290 --> 00:12:28.110 The effectiveness of DDT against lice was first proved in the field during the typhus epidemic at Naples. 00:12:28.110 --> 00:12:33.780 The 10 percent powder is applied to the hair, and distributed between clothing and skin. 00:12:33.780 --> 00:12:39.540 DDT dust is also useful in storerooms and the holds of ships. 00:12:39.540 --> 00:12:45.270 Projected through a nozzle extension, it penetrates to the haunts of roaches. 00:12:45.270 --> 00:12:48.480 It should be applied generously around cracks and crannies. 00:12:48.480 --> 00:12:56.430 The rotary duster distributes DDT dust in areas frequented by flies, roaches, and ants. 00:12:56.430 --> 00:13:02.040 Here it lies, until carried away by wind or rain. 00:13:02.040 --> 00:13:09.710 Less tenacious than the residuum of the oil solution, it is nevertheless a persisting poison against insects. 00:13:09.710 --> 00:13:16.070 If the worker stands to windward, it is not necessary to wear a mask when dispensing DDT dust. 00:13:16.070 --> 00:13:20.770 For complete mosquito control, larvaciding is essential. 00:13:20.770 --> 00:13:30.180 Solutions drifted by wind over water at the rate of one-tenth pound of DDT per acre destroy larvae within 24 hours. 00:13:30.180 --> 00:13:38.840 These obvious breeding places are rendered harmless when minute quantities of DDT are ejected from a small hand sprayer. 00:13:38.840 --> 00:13:46.950 The drip can method, wholly ineffective where there are strong currents, may be used for larvaciding still water or slow streams. 00:13:46.950 --> 00:13:57.200 The figures sound fantastic, but one part of DDT in twenty million parts of water killed all larvae. 00:13:57.200 --> 00:14:07.050 In the absence of other equipment, DDT solution may be poured onto the surface of ponds. However, this is not a preferred method. 00:14:07.050 --> 00:14:18.820 Oil solutions of DDT remain on the surface. Emulsions penetrate the depths. Therefore, the latter require heavier dosage. 00:14:18.820 --> 00:14:30.570 Whatever the method or the solution, with proper dosage, most larvae die within 24 hours. 00:14:30.570 --> 00:14:35.280 The greatest potentiality of DDT lies in dispersal from planes. 00:14:35.280 --> 00:14:42.980 This assures even distribution, coverage of otherwise inaccessible areas, and conservation of manpower. 00:14:42.980 --> 00:14:49.000 This is the only method whereby insect control may be established shortly after D-day. 00:14:49.000 --> 00:14:55.650 Five percent DDT in equal parts of diesel and lubricating oil is spread at the rate of 2 quarts per acre. 00:14:55.650 --> 00:15:02.140 Dispersal of DDT by planes combines features of three methods of treatment previously presented. 00:15:02.140 --> 00:15:11.810 Descending through the air, it kills adult insects on the wing, as the fog treatment does. 00:15:11.810 --> 00:15:20.270 Experiments and inventions are constantly being made to improve DDT formulae and methods of application. 00:15:20.270 --> 00:15:27.800 The pocket atomizer, comparable in size to a fountain pen, may soon be supplied for individual use. 00:15:27.800 --> 00:15:37.220 Work in progress indicates that DDT may also be sprayed from fast planes, or it may be dispersed explosively. 00:15:37.220 --> 00:15:47.650 In this rapidly evolving field of insect control, new methods are constantly being sought and tested. 00:15:47.650 --> 00:16:11.470 [The end. Bureau of Aeronautics. 1944. MN-3726e]