"The House Fly" 50s gross out health film (16mm)

[Music] musca domestica these latin words are the scientific name for one of the most dangerous insect pests known to man the common house fly as its name implies plagues the households of mankind around the world it cannot bite or sting but its physical structure and feeding habits make it a carrier of disease and death it spreads the organisms that cause typhoid fever dysentery tuberculosis leprosy hookworm cholera diarrhea anthrax gangrene and numerous other painful diseases parasites that inflict suffering and death upon mankind if the housefly were not such a restless explorer of everything in sight it would not be such a dangerous pest but it is equally at home as it visits back and forth between surroundings of finery and places of filth before arriving in this spotlessly clean kitchen flies may visit along the way such places as an unsanitary privy a decaying animal carcass or an opened up where diseased germs thrive in trash and garbage tests have proven that flies from a dump such as this are capable of flying as far as 20 miles away to a light perhaps on baby's birthday cake and while baby may find swatting it flies an amusing part of the celebration these germ-laden flies may bring her the unwanted gift of a bad tummy ache [Music] the two main factors which make the house fly such a menace to human health are its structural characteristics and its rapid rate of reproduction first let's consider some of the important structural features of the house fly it is a true insect it belongs to the order of insects named diptera which means two wings its two transparent wings full back to give it a triangular appearance when not flying bristle-like hairs cover parts of the fly's body these hairs are one of the means by which the fly picks up and transports millions of disease germs as it visits sources of contamination being a true insect the house fly has three distinct body parts a head a thorax and an abdomen the head bears the eyes antennae and mouth parts or proboscis the surface of each of the large compound eyes is divided into approximately four thousand facets or individual lenses the eyes of the male house fly are spaced closer together than those of the female between its compound eyes the house fly also has three or sell i or simple eyes but in spite of this elaborate equipment for seeing the housefly depends mainly on its highly sensitive antennae in detecting odors which are attractive to it the interesting feeding organ or proboscis can be retracted almost completely into the head when not extended for feeding the end of the proboscis is a spongy heart-shaped structure composed of two lips or labella which the fly presses against any substance upon which it desires to feed disease germs and parasites may adhere to the labella as the fly feeds they may then be carried to the next place the fly visits and deposited as the fly tastes or feeds on the new substance the wings and legs of the fly located on the thorax provide excellent locomotion for the fly in its incessant explorations both wings and legs in contacting filth become important factors in the disease spreading activity of the fly each of the fly's feet is equipped with a pair of claws which are used for clinging to rough surfaces some segments of the legs and feet are sensitive to taste on each foot we see from beneath a light colored structure these are the pulvilli the pulvilli have the special function of making the fly's feet stick to smooth surfaces thus the fly can walk upside down on the ceiling or climb walls with ease this feature although helpful to the fly makes the fly a more dangerous transmitter of disease sits its sticky feet pick up germs and parasites and distribute them everywhere the fly walks here we are letting a fly walk across a specially prepared gelatin plate this fly's feet are scattering the spores of a fungus picked up from some surface on which it has walked under the microscope a few days later we can see the rapidly developing fungus as a mass of thread-like branches diseased germs are spread and multiply in the same manner the house flies respiratory and digestive systems extend through the thorax and the abdomen the abdomen also encloses the reproductive system breathing is accomplished through holes or pores called spiracles in the body wall the feeding and digestive systems of the fly and still another manner in which the fly spreads disease here we have an animated diagram to give us an idea of how the digestive system functions when necessary the fly pumps saliva from its salivary glands onto its food to help soften it oftentimes it also regurgitates partially digested food from its crop to help liquefy food it wishes to eat the proboscis then sucks up the food germs included into the esophagus the pro ventriculus directs the flow of food into the crop supposing this fly were to a light next on your strawberry sundae the filthy germ infested food in the fly would be regurgitated the fly's feet would add more contamination a single housefly has been known to carry over six and a half million bacteria at one time it becomes obvious why houseflies are such a health menace after being pre-digested in the crop the house fly passes its food a little at a time from the crop and the pro ventriculus now opens the passageway to the stomach as digestion is completed the waste products are expelled through the digestive tract still laden with the germs or parasites swallowed by the fly the familiar fly specs are the regurgitations and feces of flies many of them may be deposited close together on surfaces frequently visited by flies houseflies lay their eggs anywhere they find the kind of media or food on which the fly larvae can feed when they hatch an uncovered dirty garbage can is an open invitation to breeding flies fly larvae or maggots are a common sight in unkempt garbage cans accumulations of animal refuse are also ideal breeding places for flies thousands of fly eggs may be laid in a manure pile within a few hours after the manure is dumped here you see masses of the tiny white fly eggs the heat given off by the decaying refuse helps to incubate the eggs the female fly has a long tube or overpositor through which the eggs are laid a single housefly lays an average of 100 to 150 eggs at a time and melee up to seven batches of eggs in an average lifetime of two or three weeks the pearly white eggs are so tiny that 150 of them can rest on a pencil point in warm weather the eggs usually hatch within 8 to 24 hours a slit appears in one end of the egg and the tiny white legless lava or maggot wriggles out of the egg case the maggots immediately commence feeding on the decaying food matter in which they find themselves within an average of five to 14 days in temperate zones they will be full grown larvae while they are growing they go through three distinct larval stages called in stars at the end of each of the first two stages or in stars the maggot molds its skin when ready to molt the old skin breaks open at the head or pointed end and slips off as the maggot crawls away the maggot has hook-shaped mouth parts for feeding and to help it crawl we have placed the magnet on this stick to see the crawling action more clearly and now let's watch this action in slow motion the maggot extends its body forward anchors its hook shaped mouth parts and by muscular contraction pulls its body forward maggots have no antennae or eyes but they are sensitive to light rays and they immediately seek to find cover when exposed to light the black dots on the tail end are spiracles through which the maggots breathe when fully grown the maggots reach a length of one third to one half an inch soon thereafter they move to a nearby drier area to pupate here the last skin of the maggot shrivels up and becomes the brown seed like protective coat of the pupa we will now see by time lapse photography how the color of the pupa changes in summer temperatures the pupil stage lasts an average of five days larvae which pupate in late fall may remain in the pupil stage until the following spring when the transformation from larva to fly has been completed the fly pushes off the end of the pupil case here we see flies breaking out of their pupil cases aided by their expanders the expander is a sack located on the head of the fly when it is time for the fly to emerge body juices inflate this sack causing the pupil case to split open when the fly's head is free it struggles out of its pupil case sometimes the emerging flies find it necessary to work their way up through debris such as leaves manure or sand that has covered them during the pupation period the fly's expander sac then comes in very handy by alternate expansion and contraction of the sac the fly is able to open a passageway ahead of itself and with the aid of its legs it can escape to the surface after the fly emerges from its pupil case its exoskeleton hardens body juices flow into the wings to expand them the transparent wings stiffen as they dry the fly's various body parts take on their characteristic coloration the fly's expander disappears being withdrawn into the head never to be seen or used again now a new generation of flies is ready to carry on the spread of filth and disease not too many flies heed that age old invitation come into my parlor said the spider to the fly since there are not sufficient natural controls to effectively reduce the fly population man must assume the responsibility for stopping this notorious public health enemy from wandering at will in our communities but swatting flies one by one while millions of new ones are hatching will never begin to solve the fly problem insecticide sprays though they are a great help in killing flies are only a part of an adequate control program research laboratories are constantly seeking for new methods and insecticides to control flies this entomologist is using nuclear equipment to test the food preferences of flies but sanitation is the only sure cure for the house fly minutes and sanitation begins at home each citizen's home and with each citizen's personal habits of cleanliness while this housewife properly maintains a high standard of cleanliness she may still be plagued by the flies which are bred in the filth of a distant neighborhood or a farm where sanitation is not practiced these flies represent not only a potential danger to human health for miles around but to the livestock on this and surrounding farms as well flies transmit a number of diseases and parasites from infected animals to healthy ones thus it is obvious that a serious and far-reaching community responsibility rests upon each citizen to practice good sanitation habits for example to keep the fly population down poison bait is regularly distributed around this dairy barn and of course there is no excuse for anyone helping to create such an unsightly and unsanitary mess as this roadside dump all waste products should be completely burned or buried in the city disposal of waste products such as garbage trash and sewage becomes a costly operation most cities and towns have sanitation departments in modern facilities for proper waste disposal after being collected in sanitary trucks trash and garbage is transported to municipal dumps in some cases it is used as fill for low or swampy land areas by being buried it is not only out of the reach of flies but it sometimes helps to reduce the cost of garbage collection through the increased value of the filled land some municipalities consume garbage in huge incinerators in most areas treatment plants process and sterilize raw sewage before dumping it into our waters this means cleaner lakes and streams and in turn cleaner recreational areas with fewer flies less chance of disease and better fishing since raw sewage is as destructive to fish as it is attractive to flies while civic sanitation agencies have made good progress in establishing fly control procedures only the cooperative action of each individual can ensure final elimination of the health menace represented by this prolific