Produced by Robert Rowe Charles Franksand the Online Distributed Proofreading TeamTHE STORY OF GERM LIFEBY H W CONNPROFESSOR OF BIOLOGY AT WESLEYAN UNIVERSITYAUTHOR OF EVOLUTION OF TODAYTHE LIVING WORLD ETCPREFACESince the first edition of this book was published the popularidea of bacteria to which attention was drawn in the originalpreface has undergone considerable modification Experimentalmedicine has added constantly to the list of diseases caused bybacterial organisms and the general public has been educated toan adequate conception of the importance of the germ as the chiefagency in the transmission of disease with correspondingadvantage to the efficiency of personal and public hygiene At thesame time knowledge of the benign bacteria and the enormous rolethey play in the industries and the arts has become much morewidely diffused Bacteriology is being studied in colleges as oneof the cultural sciences it is being widely adopted as a subjectof instruction in high schools and schools of agriculture andhousehold science turn out each year thousands of graduatesfamiliar with the functions of bacteria in daily life Throughthese agencies the popular misconception of the nature of microorganisms and their relations to man is being gradually displacedby a general appreciation of their manifold services It is notunreasonable to hope that the many thousands of copies of thislittle manual which have been circulated and read have contributedmaterially to that end If its popularity is a safe criterion thebook has amply fulfilled its purpose of placing before the generalreader in a simple and direct style the main facts ofbacteriology Beginning with a discussion of the nature ofbacteria it shows their position in the scale of plant and animallife The middle chapters describe the functions of bacteria inthe arts in the dairy and in agriculture The final chaptersdiscuss the relation of bacteria to disease and the methods bywhich the new and growing science of preventive medicine combatsand counteracts their dangerous powersJULY 1915CONTENTSIBACTERIA AS PLANTSHistoricalForm of bacteriaMultiplication of bacteriaSporeformationMotionInternal structureAnimals or plantsClassificationVariationWhere bacteria are foundIIMISCELLANEOUS USES OF BACTERIA IN THE ARTSMaceration industriesLinenJuteHempSpongesLeatherFermentative industriesVinegarLactic acidButyric acidBacteria in tobacco curingTroublesome fermentationsIIIBACTERIA IN THE DAIRYSources of bacteria in milkEffect of bacteria on milkBacteria used in butter makingBacteria in cheese makingIVBACTERIA IN NATURAL PROCESSESBacteria as scavengersBacteria as agents in Natures foodcycleRelation of bacteria to agricultureSprouting of seedsThe siloThe fertility of the soilBacteria as sources oftrouble to the farmerCoal formationVPARASITIC BACTERIA AND THEIR RELATION TO DISEASEMethod of producing diseasePathogenic germs not strictlyparasiticPathogenic germs that are true parasitesWhatdiseases are due to bacteriaVariability of pathogenic powersSusceptibility of the individualRecovery from bacteriologicaldiseasesDiseases caused by organisms other than bacteriaVIMETHODS OF COMBATING PARASITIC BACTERIAPreventive medicineBacteria in surgeryPrevention byinoculationLimits of preventive medicineCurative medicineDrugsVis medicatrix naturaeAntitoxines and their useConclusionTHE STORY OF GERM LIFECHAPTER IBACTERIA AS PLANTSDuring the last fifteen years the subject of bacteriologyFootnote The term microbe is simply a word which has been coinedto include all of the microscopic plants commonly included underthe terms bacteria and yeasts has developed with a marvellousrapidity At the beginning of the ninth decade of the centurybacteria were scarcely heard of outside of scientific circles andvery little was known about them even among scientists Today theyare almost household words and everyone who reads is beginning torecognise that they have important relations to his everyday lifeThe organisms called bacteria comprise simply a small class of lowplants but this small group has proved to be of such vastimportance in its relation to the world in general that its studyhas little by little crystallized into a science by itself It isa somewhat anomalous fact that a special branch of scienceinteresting such a large number of people should be developedaround a small group of low plants The importance of bacteriologyis not due to any importance bacteria have as plants or as membersof the vegetable kingdom but solely to their powers of producingprofound changes in Nature There is no one family of plants thatbegins to compare with them in importance It is the object ofthis work to point out briefly how much both of good and ill weowe to the life and growth of these microscopic organisms As wehave learned more and more of them during the last fifty years ithas become more and more evident that this one little class ofmicroscopic plants fills a place in Natures processes which insome respects balances that filled by the whole of the greenplants Minute as they are their importance can hardly beoverrated for upon their activities is founded the continued lifeof the animal and vegetable kingdom For good and for ill they areagents of neverceasing and almost unlimited powersHISTORICALThe study of bacteria practically began with the use of themicroscope It was toward the close of the seventeenth centurythat the Dutch microscopist Leeuwenhoek working with his simplelenses first saw the organisms which we now know under this namewith sufficient clearness to describe them Beyond mentioningtheir existence however his observations told little or nothingNor can much more be said of the studies which followed during thenext one hundred and fifty years During this long period many amicroscope was turned to the observation of these minuteorganisms but the majority of observers were contented withsimply seeing them marvelling at their minuteness and utteringmany exclamations of astonishment at the wonders of Nature A fewmen of more strictly scientific natures paid some attention tothese little organisms Among them we should perhaps mention VonGleichen Muller Spallanzani and Needham Each of these as wellas others made some contributions to our knowledge ofmicroscopical life and among other organisms studied those whichwe now call bacteria Speculations were even made at these earlydates of the possible causal connection of these organisms withdiseases and for a little the medical profession was interestedin the suggestion It was impossible then however to obtain anyevidence for the truth of this speculation and it was abandonedas unfounded and even forgotten completely until revived againabout the middle of the 19th century During this century ofwonder a sufficiency of exactness was however introduced intothe study of microscopic organisms to call for the use of namesand we find Muller using the names of Monas Proteus VibrioBacillus and Spirillum names which still continue in usealthough commonly with