one of the laboratories at the city health department his brother frank has recently taken a position as a bacteriologist with the department ted seems to be having a little trouble going to get a focus on the field bacteria bacteria are found almost everywhere in our environment some float around in the air some are in water or other liquids still others thrive in the soil bacteria are plants but they are not green like the plants we usually see some kinds are indispensable for example complex bacteria are at work in this cloverfield they are growing in the little not jewels at the plant roots bacteria in these not jewels take nitrogen from the air and change it into a four plant food other kinds of bacteria are responsible for milk or cream becoming soured the development of flavor and other qualities in cheese and the disintegration of dead plants and animals in fact the effects of bacteria are so important that life as we know it would be impossible without them most bacteria are friends of man some even produce chemicals called antibiotics that are used to help fight different diseases only a few kinds bacteria cause disease probably the first person to observe bacteria was antony funnell even took inventor of one of the first successful microscopes and after looking through his crude microscope he made drawings of the microorganisms he saw these represented organisms from cancers scraped from his own teeth in contrast here using a modern microscope we see other microorganisms taken from t to the time of late in the book generations were to pass before another achievement of great importance would be made in the study of bacteria it was the same chemist louis pastore of france who in the eighteenth fifties proved that this explained many of the chemical changes that go on in nature that still are also prove that bacteria never develop out of dead organic matter alone as some people had believed he emphasized that bacteria can only come from other bacteria soon afterward it was found that bacteria can spread disease from a sick animal to a healthy animal but this discovery was made by koch a german contemporary a pastor this discovery is the basis of the germ theory of disease robert koch and his assistants also learn to prepare and use nutrient materials nutrient materials are usually jelly like emotions or fluids which favor the growth of bacteria cook made other discoveries that helped lay the foundations of modern bacteriology since the time of koch much has been learned and many other kinds of bacteria discovered today if ted could collect all known kinds of bacteria he would have thousands and the facts that have been discovered about them are exceedingly numerous he wonders how a beginner can ever learn about so many kinds of bacteria frank explains that it takes a systematic approach for example bacteria may be separated into groups according to what they live upon the nature of the food they require some bacteria are parasites others sacrified and still others  parasites depend upon living plants or animals for food here are some parasitic bacteria most bacteria that cause human disease are parasitic separate fights live upon dead plants or animals or their products separate phytic bacteria produce enzymes that cause a chemical breakdown we call decay there are more kinds of separate phytic bacteria than of any other type get their energy from minerals or other inorganic materials the autotrophic bacteria seen here live upon a form of iron through oxidation they change one form of iron into another and use the energy that is released unlike the large majority of plants most bacteria have no chlorophyll with which to manufacture food parasites sacrified and autotrophs all take in food through their cell walls to pass through the cell walls the food must be soluble in some instances insoluble foods are converted into soluble materials by chemicals released by the bacteria themselves all bacteria require soluble food to live te thinks the information seems complicated but frank speaking from experience explains that the basic facts about bacteria are quite simple and very useful besides facts about the food getting a bacteria frank describes another type of information that is especially useful in bacteriology depending upon the structure or shape of bacteria there are four main kinds the cox side that are round like these that are common in the air the saliva that are rob shaped like these from gas going green the spiral that are spiral likely is taken from a sample of well water and the filamentous forms such as the thread like one structure or shape is one  principal characteristics used by bacteriologists to classify or identify different kinds of bacteria the life processes of bacteria are simple we've already seen how bacteria obtain food now we will consider their reproduction which takes place through simple division of the cells in drawings we can see the bacterium cells are continually growing when a cell reaches maturity it divides again this goes on and on about every half hour as long as the food supply holds out or until some unfavorable conditions slows down or stops their development the reproduction rate of bacteria may be greatly affected by temperature in a laboratory the temperature can be controlled in an electric incubator as frank explains there is always a temperature that's best for growing bacteria usually the temperature is about thirty to thirty seven degrees centigrade thirty seven degrees centigrade is about equal to the normal human body prichard in case the temperature is unfavorable some bacteria especially the rod like kinds have a special means of protecting themselves they do it by forming spores notice the store forming in the center of one of these bacterium cells some other kinds of bacteria form spores at the ends of the rods instead of at the  either way a spore has a special wall around itself that seems to protect the bacterium inside from such adverse conditions as cold heat sunlight or disinfectant later when conditions improve the spoor may change back again into the rod like bacterium not many disease producing bacteria go through us poor form besides protective mechanisms some bacteria are equipped to move about the hair are equipped like parts attached to these bacterium cells are called flagella different types of bacteria have different types of blood jalen such the giallo can be moved to propel a living bacterium through blood or other solutions not all bacteria have such means of locomotion koch germinate have made discoveries and invented techniques indispensable in successfully preparing nutrient material growing cultures and subjecting the cultures to tests that help identify and classify bacteria today in bacteriology laboratories work is conducted that leads to the control of the relatively few bacteria that are foes of mankind and to the more effective use of the multitudes that our friends in order to make human life more healthful and increase our standard of living