LIBRARY XJOTVERSITY OF CALIFORNIA DAVIS Digitized by the Internet Archive in 2007 with funding from IVIicrosoft Corporation http://www.archive.org/details/civicbiotextbookOOhodgrich PLATE 1. A MAN-MADE PARADISE Ol{ A MAN-MADE DP:.SKKT. WIllCHr CIVIC BIOLOGY A TEXTBOOK OF PROBLEMS, LOCAL AND NATIONAL, THAT CAN BE SOLVED ONLY BY CIVIC COOPERATION BY CLIFTON F. HODGE, Ph.D. PROFEABOB OF SOCIAL BIOUXJY IX THE ITNIVEK8ITY OF ORFXK>N AUTHOR OF "XATtKE STUDY AND LIFE" AND JEAN DAWSON, Ph.D. DBFABTMRNT OF SANITATION, BOAKD OF IIKALTH, CLKVELANP rOBMERLY OF MACIM»NALI> roLI.KOE, CANADA, AND C'LKVELAND NOKMAL SCHOOL; AI'THOR OF "THE BIOLOGY OF FHYKA" AND "BOYS AND OIULS OF GARDEN CITV " It will loach only such iwes of authority a« are necpssary to necure cooperation of several or many people to one end ; and the discipline it ^vill advocate will l)e training in the development of coui)erative good will. — Charles W. Eliot. GINN AND COMPANY BOSTON • NEW YORK • CHICAGO • LONI>ON ATLANTA • DALLAS • COLUMBUS • SAN FRANCISCO LIBRARY UMTVERSITY OF CALIFORNIA • DAVIS COPYRIGHT, 1918, BY CLIFTON F. HODGE AND .JEAN DAWBON ENTEKED AT STATIONERS' HALL ALL RIGHTS RESERVED 318.10 GINN AND COMPANY • PRO- rUlETORS • BOSTON • U.S.A. PREFACE Discovery is pushing forward in every direction as never before in the history of the world, and still it would seem that enough is already known to make living well-nigh ideal and the world almost a paradise, if only enough people knew. In how many of our civic units does ever^' citizen know enough to conserve effectively the valuable bird life, the trees, the soil, and water on his own premises, to exterminate the rats and English spaiTows, the flies, mosquitoes, and San Jose scale, the hookworms, diphtheria, and tuberculosis germs ? If every individual citizen knows enough to do these tlnngs, in how many communities do all the people know enough to cooperate, — to work together Avith efforts so timed and planned that the good work of one, or of all but one, shall not be rendered vain by the failure of someone else to do liis part? The tides and currents, storms and floods, of living nature are too vast and powerful to be held within any dikes less se- cure than those built by the common, united effort of the whole community. The measure of our present need is seen in the wastage and loss that is streaming tlu:ough our ineffectual defenses, — the probably not less than five hundred thousand valuable lives sacrificed annually to the currents of prevent- able disease, along with the several billions of dollars' worth of foods and other property swept away by rats, insects, weeds, and fungi. How much higher must the cost of living soar before we begm to awake from the dream that we are a scientific and efficient people ? As we are now organized iii 395807 iv CIVIC BIOLOGY (or, rather, disorganized), who knows whether his next- door neighbors know what to do in solving common civic problems ? From the way they do and live he may conclude that they do not know, but they may all be passing the same judgment upon him. So, instead of each one doing his civic part, and knowing that the rest are doing theirs, we are caught at every turn in the do-less net of " what 's-the-use- ness." A would gladly protect his birds, but not to feed Mrs. B's cats. C could easily extermhiate his own flies, but they continually swarm over from D's filthy premises. And so it goes for the thousand and one civic problems, — at every turn the deadly question, " What 's the use ? " How can we extricate ourselves from this net? Cooperative good will is the essential idea in civic biology, as it is in the progress of civilization itself. This means that civic biology consists of all those problems whose solution requires cooperative effort. In the nature of the case we cannot control many of the forces of living nature by any amount of uncoordinated individual effort, any more than we can turn back the ocean tides by haphazard sweeping with brooms. The problem of civic biology, therefore, is to make it possible for everyone to know what these forces are, for good or for ill, and to understand how to do his part for his own good and for that of the community. Cooperative build- ing of the defenses offers our only hope of success, and our education needs to be so organized that every citizen shall know enough to stop a breach the mstant he sees it. Acknowledgments in the text accompany pictures and other contributions, except in the following cases : The figures of ticks, in Plate IV, are rearranged from those published by the United States Department of Agriculture and the United States Public Health Service. The upper view hi the frontispiece is taken from a photograph looking northward PREFACE V down the Hood River valley, Oregon, across the gorge of the Columbia, with Mt. Adams in the background. It is used by the courtesy of the United States Reclamation Service. The lower view is from one of Bailey Willis's photographs of Shingkung, China, and shows desert conditions, man-made within the short space of about the last two centuries. With complete deforestation of the mountains, the once fertile valley has been buried under the wash of floods, which, alternating with burning droughts, have made the country uninhabitable. We are indebted for use of the print to the Carnegie and Smithsonian institutions. The idea of the book is expressed at a glance in the fron- tispiece, the question " Which ? " being applicable to every landscape and home in the world. C. F. H. J. D. CONTENTS CHAPTER lAGE I. Plan of. the Coukse as a Whole 1 II. Equipment, Apparatus, and Libkaky 10 III. The Insect Problem 18 IV. Birds 2:] V. Methods of Bird Study and Special Problems . 35 YI. Tree Study and Civic Forestry 55 VII. Plant Problems : Preservation ok Wild Flowers, Control of Weeds, Medicinal and Poisonous Plants 67 VIII. Home PLANTiNoi liars, and 43 . Photograph by the author grasshoppers, & i j amounting to three ounces of food. An adult cuckoo ate 225 cabbage cater] tillars, or 150 large woolly caterpillars, amounting to about five ounces of food daily. (From feeding tests by Andrew J. Redmon.) From such actual data as these we learn that the estimates given above are conservative. Much more accurate observation is required, however, before entirely reliable estimates can be made. Outdoor laboratory work. This should extend throughout the year, and also to combine problems requiring continuous ^ All the above data are taken from reports of students of the Indiana University Summer School, Winona Lake, Indiana, for 1905 and 1906 (O. P. Dellinger in charge of class). 26 CIVIC BIOLOGY observations upon birds, insects, trees, fungi, weeds, native flowers, and common plants, elaborate the following plan as early in the year as possible. Let two students combine upon the same tract of land, in order to secure greater completeness of the practical work, but each should make his own field charts in as careful detail as if he were working the tract alone. Select some readily accessible piece of land of limited area. On a farm, the home lot with the dooryard, garden, orchard, and grove will be most suitable. The village lot of an acre or two is exactly adapted to this work. In an open city the home lot, if well planted, may prove the best selection we can make, but probably the residential block in which the home stands will provide necessary variety and scope. For the crowded city we must have recourse to public parks and gardens, and to accessible tracts in the suburbs, for the study of which defi- nite permission can be obtained. The tract should present, if possible, a variety of natural features, — hill, meadow, ravine, brook or edge of pond, and especially variety in plant forms, — lawn, garden, orchard, field, meadow, woods. A variety of shrubbery and low-growing trees makes a tract preferable to one with very tall trees, which are difficult and unsatisfactory to work. By properly dividing the neighborhood among the class, however, all the important features of the locality may be covered, and this will add interest and completeness to the work as a whole. As a preliminary, draw an outline map to convenient scale, and with due regard to points of the compass. Within this, first sketch in standard contour lines and indicate location of water, marsh, swamp, rock outcrops, and all buildings and superficial subdivisions, — lawns, gardens, orchards, fields, pastures, woods. We are now ready to plot the details. Count and locate all the trees, vines, and shrubs, and indicate clearly the areas cov- ered by different plants or crops. Locate all birds' nests and STREET -«r#- spruce --^Mulberr O^ d 0 Pear ^ **-« Peach fe» © t'^ %;^ ^ ■'G? Mb ''tin House [ffi' " Vegetables 1-- Gcoseoernes i /I; Fig. 10. An ideal bird-study tract 27 28 ( IVIC BIOLOGY determine the species as far as possible, indicating them by some device, like the initial letter of the name, on the plat. This work should be completed as soon as possible after the leaves fall in November. By inquiiy it may be possible to locate nests that have been '' collected " or destroyed by storms during the summer. Tliis will give a " census " of the bird population of the tract. The main question which this investigation is designed to answer is, Are there enough birds in the area to hold the insects in check ? To aid in answering this question examine the district minutely for evidences of insect depredations, and make a list of important msect pests found upon it. Examine at least 100 of each variety of apple, pear, quince, possibly peach and plum, and tabulate the percentage of the different fruits injured by insects. Gather similar data, if possible, for the earlier fruits, — strawberries, gooseberries, currants, — and also for the various garden vegetables and other crops grown in the tract. Add to the bill of damage the cost of materials, apparatus, and labor expended in fighting insects. On the otlier side of the balance sheet record with equal care any injury caused by birds. Note wliat kind of birds caused the damage. From all you know and can learn of bird life try to discover what special features attract the birds to nest on the tract, — water, food, suitable nesting sites and materials. Suitable and accessible water for drinking and bathing will be found to be one of the main factors, and food supply and absence of enemies, other elements. Never lose an opportunity to see what a bird is doing, — what it is searching and finding for food. Clear observation on this point seldom fails to answer the question, Why is the bird here ? Study with equal care all the elements which can account for a scarcity of l)irds or the absence of particular species. What necessities of bird life are lacking? What natural BIRDS 29 enemies of the different species are present ? Mucli of this side of the prob- lem will be worked out naturally in connection with nestuig habits, the study of nest building, and the fate of the differ- ent nests in the spring. Pay particular attention to the bird-food plants of the area with reference to abundance of food at dif- ferent seasons. Note the condition hi this respect for the different months. Is the area stripped of available food by the time robins and bluebirds have migrated in the fall ? May this help to explahi bird migrations ? Note in detail what pro- visions have been made in your district to supply the necessaries of bird life, — bird houses, drinking and bathing fountams, plant- ing of food trees. AV^hat is done to protect the birds from enemies ? What in- fluence have these provi- sions exerted on the bird population as compared Fn}. 11. Bird fountain. Natural rocks laid in cement with deep chinks filled with soil and planted with mosses, ferns, and wild flowers fhutoinraph l>y the author 30 CIVIC BIOLOGY with neighboring districts in which no such provisions are made ? What is the practical vahie of such work as shown by your account of insect injury ? of losses caused by birds ? Other important Imes of bird work relate to destruction of weed seeds and the control by owls, hawks, and slirikes of nox- ious mammals, — mice, moles, rats, gophers, etc. Keep these matters in mind throuo^hout the year wliile doing the field work. Fig. 12. Bird house for study of home life ; windowpane is back wall of house Photograph by the author The birds in your district will change during different sea- sons. During, the fall migration the " summer residents " will leave for the south, and many species whose breeding range is farther north will migrate through the territory. These species may be designated as "transient visitants." They migrate by us to the northward in the spring and southward in the fall. After settled cold weather begins there will be left the " per- manent residents," — about thirty-six species for the latitude BIRDS 31 of New York (Chapman), — and " winter visitants," seventeen species of birds that come from the north and spend part or all the winter. Make provision for the winter birds. Suet and a piece of fat pork may be tied to a branch of a tree, with a tray also fastened to the trunk, in which seeds (millet, corn, sunflower, pumpkin, or squash) and cracked nuts (butternuts are espe- cially good) may be kept, and on the ground close by a pile of chaff or loft sweepings. The purpose of this is to attract all the winter birds within range of easy observation. The tray may be attached to the living-room window sill, if on the south side of the house, an attractive branch may be fastened at the side of the window, and the heap of chaff may be put under it, close to the house. This latter must be kept free from snow through the winter. The work of the year is intended to yield a complete pic- ture of the life and work of the birds in your district. At stated intervals your observations should be carefully written up under various heads. We suggest the following : September — My Bird Study Tract (giving chart and descri[>tions of natural features). October — To what Extent do Birds prevent Insect Depreda- tions? November — The Fall Migration of Birds. December — Winter Provision for Birds, — Permanent Residents and Winter Visitants. February — The Work of our Winter Birds. March — My Plans for Bird Work this Spring. April — Birds' Nests ; Nest Building ; Nesting Sites of Different Species ; Materials. May — Bird Songs and Notes, and what they mean. May — Feeding Habits of Birds. May — My Observations on Feeding of Young; Amount of Insect Food. June — Summary and Results of my Bird Study for the Year. 32 CIVIC BIOLOGY Other more general topics, like the following, are suitable as assisfnments for different members of the class to work out and report upon toward the close of the year : The English Sparrow in the Locality may be subdivided into : Ke- latious to Native Birds ; Damage caused by ; Methods of Extermination. The Life and Work of the Bluebird. (Substitute the name of any other common bird, if desired. It w^ould be well if each member of the class could devote special attention to working up the life t)f some important species.) By a free interchange of notes these reports may be made more complete, and in this way each is made the summary of the work of the whole class upon the topic. We may vary and enliven tlie reports by casthig them in the form of debates about bird problems that are in dispute in the neighborhood. For example : Resolved, that the robin merits ])rotection. (Substitute other birds.) Resolved, that the crow should be exterminated. Resolved, that there should l)e a bounty on hawks and owls. Resolved, that the bobwhite should l)e placed on the protected list for a period of ten years. Resolved, that spring shooting of waterfowl ought to be prohibited by law in all states. Resolved, that active measures be taken to establish a preserve for the breeding of grouse and waterfowl in this township. Resolved, that it is better policy to preserve native s[)ecies than to import grouse from other countries. Resolved, that the killing of song and insectivorous birds f(^r milli- nery purposes is legitimate. Resolved, that a person who allows his cats to kill birds should be subject to the same fine as if he killed them himself. Resolved, that a law be passed making owners of cats responsible for the birds they kill. Resolved, that it is an unwarranted waste of bird life to make ^^^ collections. This list might be extended indefinitely. Birds are divided popularly into " soft-billed," eating mainly worms, insects, and berries ; and " hard-billed," feeding upon i g 1 i C/l u OL -i JSJSS l'«^f?:^*=:==:"--" *:=E===Bi== + +: + ml:::: ^^^6^^^^^*+* i» ♦. -I -- ^^^^ C^^'**n ■i'^' _i* "F * ^^'«^^J^-'^^ 1 } t + *. ^uc^'^oflS -"^^ ' ^M 1 ' +' 1 . ± ^S^'B^^' --^'^ ' ' ;+' 1 t + J^ijt^^-'^^ ,^^^ ++I ' 1 1 * + +- ^± 5^nW-^«S^ -^'"'^ 1 ' 1 "^ *1.. !+ + ^^J6%^ -"^^ ■*■' ' ►" ! 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' ' ' 1 !![: 1 ^A^^&i^ • + +-,^*^+ i + + + ' + + + '+ 1 H k*i« I++ + M*,^^\M^i>^,.-^l«++5''^S* + + j +i !+.!':+ ' + + +' ++«+■ -+5$ + + S^t^'-^^' U4i 1 |a*l3+M '++. !■ + + + + + + + ++ + +>+'«+• .^1+^*++*" Wllfot^*'-':^! U! «-+ + ++ + I-+ + + + + ++«'*i+ MM N§Mv\^'^V' sl l+si8t!s;+!+ ++ + + + + = + + + + + += + +r.Si2i i+i j«| 0^ft^^,-'d + + S «>«£+:+ + + + + + ++ ++ +3 r. + +5:s+!+| | U| s : :?:,s,?;;3,s 2 : |s:2ir •J ISIJ '51 f^t^^^Ss^Tlh^-i 1 = ' \ siJ:sis:?tiS:§ss^g|: siSs [=1 ^'-'^ = ill Jgs^j i id i Euea2o m C3 p: o a ^ ,t ■^ «S w 1 ^ TJ n (U t/j & Pi W 5 ^ o rr' ^ 1^ ? ;s «M o 3 ?3 s c o br <4-l cs o a 1 -s ^ TU -2 O eg o Vi »?? fl CO CC 1— 1 o « Ph >~] s & t. fe 33 34 ' CIVIC BIOLOGY seeds. Both classes, however, feed the young mainly on in- sects. Our gardens, fields, and roadsides are weedy enough, but who can imagine what they would be, were not thousands of tons of weed seeds destroyed annually by the sparrows, bobwhites, doves, larks, blackbirds, and others. About fifty species of birds are efficient weed destroyers. Compare and draw a few typical hard and soft bills to fix this distinction. Beal has estimated that the tree sparrows alone in the state of Iowa destroy annually about 875 tons of weed seed. Are both weeds and seed-eating birds abundant in your bird tract ? Hawks, owls, and shrikes render service in destroying noxious mammals. Are the mice, rats, field-mice, or gophers numerous in your district, and what amount of damage do they cause by eating grain or girdling trees ? Dr. C. Hart Merriam has estimated that a bounty act. on hawks and owls, during its operation in Pennsylvania for a year and a half, cost the state not less than $4,000,000. The accompanying food chart shows about all we know of the foods of many of our commonest species. The blank squares in the chart indicate generally deficiencies in observa- tion, and not that any particular bird does not eat any par- ticular insect ; hence they are in reality the most interesting part of the chart because they suggest further study. Observe the birds in your district, or, if you have a young or disabled bird, make definite feeding tests and record the results in your food chart. The chart will thus enable you to feed intelligently many birds that come to hand, and also to add to our knowl- edge of the subject. The probable diet of any bird not named on the chart may be judged from that of its near relatives.^ 1 The authors would ■ be grateful if those who make such feeding tests would send them any data secured. CHAPTER V METHODS OF BIRD STUDY AND SPECIAL PROBLEMS I have no doubt, therefore, that the wild pigeon is still with us, and that if protected we may yet see them in something like their numbers of thirty years ago. — John Burroughs, 1906 In order to do the work outlined in the last chapter we must know the birds. It is supposed that practical acquaint- ance with the commoner species has been begun in the nature study of the grades. The present course is planned as an " ad- vanced," and, so far as school life is concerned, a final year of bird study, which shall organize and complete previous knowl- edge, work out more thoroughly as practical problems the values and uses of different species, and help to answer the question, '^ How may a community make the most of its bird life ? " If we are to have intelligent progress, every one must know these things, because the ignorance of one may vitiate the best efforts of a community. After completing plans for individual bird-study tracts, dis- cuss in the class what species merit a place in the year's course. Each member may present a list including his choices, and from these the official list for the year may be selected. The lists should be changed somewhat from year to year, 'as conditions change and emphasis is shifted from one to another group of problems. In this connection, as well as in the general problem of organizing our knowledge of birds, scientific classification is of great assistance. Scientific books have described for the world 12,500 species of birds, and of this number 768 belong to North America. This large number of species means that 35 •r t- c ^1 M ^ X Ph -^ If - y. ?A\ METHODS OF BIRD STUDY 37 biixls have become differentiated to fit all sorts of envii'ounieiits, — air, water, marsh, prairie, and forest. Those of similar activi- ties, like machines built and adjusted to their work, have come to have similar structures, — of body, Aving, foot, and bill. Discovery of these adjustments will add fresh interest at every turn and mcrease respect for scientific bird study. Fig. 8 is designed to fix in mind the fundamental relations of the dif- ferent orders to environment. Common names often vary in Primaries Primary Covert Greater (-averts Middle Coverts Lesser Coverts ilnla or Spurious Wing Crown Median Line-^ Mandihles{2^r Lore SuperclUary Line Ear Coverts or Atiriculars Tail Coverts Rump Back Scapulars Wing Bars Shoulder Tibia Tarsus Vi(.. l.'). Topography of a bird C. A. Reed different parts of the same country. Scientific names are the same for all languages the world over, and this is the time to learn them, if they are ever to be remembered. Again, in order to describe birds quickly and accurately — and as a help to seeing them properly — we must learn to name the external parts, the so-called " topography " of a bird. The terms in Fig. 15 are, in the main, self-explanatory. The " primaries," " secondaries," and " tertials " are attached respec tively to the hand, fore-arm, and upper-arm bones of the wing. The following list, suited to central New England, is given merely by way of suggestion, as if the writer were a member 38 CIVIC BIOLOGY of the class. Several species not now found in the territory are included because they are related to problems which every intelligent member of the nation ought to be helping to solve. Order Pygopodes ("rump-footed") — diving birds. The birds of this group enliven our waters, and the loons give us some weird music. While anglers may object to sharing the fish with them, the main question is whether we prefer to see them on our ponds and lakes or on the ladies' hats. The two common species within our territory are : Pied-billed grebe — Podilymhus pddiceps. Loon ; great northern diver — Gdcia imber. Order Longipennes (" long- winged ") — gulls, terns, etc. The gulls and terns have required active protection in recent years to prevent their extermination by the egglers and plume hunters. What would our seascapes be without them? The protection which has been accorded these birds is one of the most encouraging signs that values other than mercenary are beginning to be appreciated. Aside from their beauty, these birds are much-needed scavengers of our harbors and coasts, and .the inland species are most efficient destroyers of insects. Two common types are : Herring gull — Ldrus argentdtus. Common tern — Sterna hirundo. Order Anseres (anser, " a goose ") — ducks, geese, swans. The problem of our waterfowl is nearing its final stage. ^ The vast breeding grounds in the Northwest are now open to sports- men and settlers, and when the wild fowl have been extermi- nated from these, as they have been from their more southern ranges, the work of destruction will be complete and final. It is high time this is appreciated as a national problem, and effective measures taken toward its solution. The first step, 1 See H. K. Job, Country Life in America, April, 1906. METHODS OF BIKD STUDY 39 it seems clear, should be total prohibition of spring shooting from Florida, the Gulf, and Mexico to the Arctic Ocean. Next, we should offer, for a period of years at least, com- plete protection and every inducement for all birds of this order to breed throughout the United States, wherever a pond, marsh, or lake can be guaranteed as a safe and permanent " preserve." All kinds of waterfowl quickly learn where they are safe, and if unmolested become tame and breed in great numbers even in small ponds. Is there a chance for a preserve in the neighborhood ? The wood duck is already on the verge of extinction and should be absolutely protected in every state. Nests discovered in the neighborhood should be guarded from disturbance. In New England, for a term of years, let the broods go unmolested even in open season on the chance that more may return to breed the followmg spring. On the mur- derous and stupid prmciple, ^' If I don't shoot it, some one else will," the last wood duck will fall to the ground and the race of our most exquisite waterfowl be extinct. Extermina- tion of a valuable species is not only a national calamity, but a national crime, — a piece of monumental stupidity and folly as well. Let us change the above principle to read, "If I have the decency and sense to spare, some one else may." To the problem of increasing and protecting our waterfowl and reestablishing them throughout their native breeding ranges should be brought the best energies of the class. All members of the order should be considered in the light gained from a study of the following types : Wood duck — A ix spdnsa. Mallard duck — .4 nas platyrhynchos. Pintail — Ddjila acuta. Whistling swan — Olor columhidnus. Canada goose — Brdnta canadensis. Trumpeter swan — Olor huccuvdtor. Order Herodiones {herodios^ " a heron ") — herons, storks, etc. These birds of our marshes and swamps are mainly of aesthetic interest and value, and although they eat a few fishes, frogs, and 40 CIVIC BIOLOGY snakes, they are, on account of this value, accorded the protec- tion of the law in Massachusetts. As examples we may take : Night heron — Nycticorax mevius — a generally common species. Snowy egret — Egi-etta candid issima — a Southern species, but one which ought to be known to every American Xorth and South, in order to save it from extermination by the milliners. Order Limicola (limus, "mud"; colercy "to dwell") — shore birds. Many of these birds of our marshes and muddy shores, wet brook beds, and upland pastures, merit protection on ac- count of their valuable service as insect destroyers, and also because of the imminent danger of extermination in which several of the best species stand. The argument given for the wood duck applies with more than double force to the wood- cock, because the former produces from eight to fourteen eggs to the woodcock's four. The same preserves would serve for the waterfowl and shore bu-ds as well. Several of the plover are in great need of protection, but the five species that follow are possibly all we can begin with, and will serve to illustrate the problems of the group: Woodcock — Phildhela mi7ior. Spotted sandpiper — Actitls maculdria. Wilson snipe — Gallindgo delicdta. Eskimo curlew — Numenius horedtis. (iolden plover — Charddrius dominicm. Order Gallina (gallus, "a cock") — grouse, pheasants. The problem in regard to all the birds of this order is again that of protectmg those that remain, and of reestablishing in their original ranges such species as have already been exterminated from certain regions. Were it not for stray and uncontrolled cats we could make town and city parks — in fact, the limits of all villages, towns, and even cities — preserves for grouse and waterfowl. We could in this way place them where the greatest number might enjoy seeing and hearing them ; while a constant supply would overflow the preserve limits for our sportsmen. Special problems occur with each of the five follow- ing types suggested for study. Fir.. 16. Ruffed grouse cock strutting Fig. 17. Bobwhite cock caring for brood of fifteen chicks which he incubated and hatched Photograph by the author 41 42 CIVIC BIOLOGY Bobwhite — CoUnus virginidnus. This species, if sufficiently abun- dant, could probably become our most important insect- and weed-seed- destroying ground bird for garden and field. The crop of one bird contained 101 potato beetles, another two table spoonfuls of chinch bugs, and another 15,000 weed seeds. Winter protection and feeding is another problem which should receive attention. Ruffed grouse — Bondsa umbellus. Wherever at all scarce, this finest of our game birds should be provided with safe covers which will insure its increase in the locality. Heath hen — Tympanuchus cupido. This species presents the problem of a numerous and valuable game bird, once generally distributed over New England and now reduced to a few pair confined to the oak barrens of Marthas Vineyard. It is a slightly variant woods form of the Western i^rairie chicken, which is rapidly being exterminated from the Missis- sippi Valley. Every effort should be made to save this remnant, and with it restock the mainland under condi- tions which shall insure the heath hen's regaining its original range. Mongolian or ring-necked pheas- ant— Phasidnus torqudtus. This is an introduced species, concerning the value of which there is much ques- tion at present. Wild turkey — - Meledgris gallopdvo. As far as New England is con- cerned we must write the word " exterminated " after the name of this our largest game bird. By concerted action, and with a suitable game preserve, might the wild turkey not be reintroduced ? Would it not be worth while ? Fig. 18. Ruffed grouse cock drumming Photograph by the author Order Columba (columboy "a dove"). The pigeons and doves the world over are among our most valuable food and game birds. The dodo of Mauritius and the solitaire of Rodriguez were gigantic ground pigeons as large as swans, but with wings METHODS OF BIRD STUDY 43 too small for flight. The last record of the dodo was in 1681. Both of these remarkable species were unwittingly extermi- nated by the introduction into the islands of hogs, which de- stroyed their eggs and young. There are in North America ten genera and seventeen species and varieties of pigeons and doves. Most of these are Western and Southern. The two named below suggest most important problems for eastern North America. For the Rocky w ^P Fig. 19. Egg of passenger pigeon, on black velvet, in nest of mourning dove The pigeon laid only one ^g^, about \\ inches long; the dove, two eggs about 1 inch long. This figure thus furnishes a decisive means of distinguishing the two species. Photograph from specimens in the American Museum of Natural History Mountain and Pacific States the types studied should be the band-tailed pigeon, ColUmha fascidta, from British Columbia to Mexico; Viosca's pigeon, C.f. vidscce, southern Lower Cali- fornia ; and the red-billed pigeon, C. flavirdstris. Passenger pigeon — Ectopisies migratorius. This most valuable of North American pigeons existed less than forty years ago in flocks which stretched from horizon to horizon. It is now a serious question wkether the last living specimen has not been seen. 44 CIVIC BIOLOCIY (For three years past rewards aggregating over |oOOO for discovery and report of undisturbed nesting pairs or colonies of passenger pigeons, anywhere in Xorth America, have remained unclaimed, and no tangible evidence has been received of pigeons killed or even seen during this time. This is commonly accepted as proving the species extinct in the wild state. One old bird still survives in the Cincinnati Zoological Gar- den. If nesting pigeons are ever found, they should he most carefully safeguarded, and all protective agencies, private, state, and national, bo focused on their jn-eservation and increase.) Mourning dove — Zenai- diira macroura caroline/isii<. Every effort is now being made to save this species in New England. It is abun- dant in the South and Afiddle West. Order Raptores {raptor^ " a robber ") — hawks, eagles, owls. The luiwks and owls furnish perhaps the most complicated and difficult problem con- nected with our bird life. By many of the best authorities the majority are accounted among our most valuable birds, on account of the great num- bers of noxious mammals — field mice, gophers, rats, etc. — which they destroy. Most of the hawks, too, feed largely on insects when they are abundant, and take comparatively^ few birds, either tame or wild. In determinmg the value of birds in this class, however, it is always an open question whether the few insectivorous birds, — which may form only 1 or 2 per cent of the hawk's total food, — if allowed to live, might not have done much more valuable work than the sum total of the predacious species. We must leave questions of this kind to be worked out from practical experience and observation. Fit;. 20. Y(^uiiii' red-shouldered hawks METHODS OF BIRD STUDY 45 When depredations on the poultry yard or disturbance among small birds is marked, it is all but certain that either a sliarp-shinned or a Cooper's hawk is causing all the mischief, lliese two, of the commoner hawks, feed almost exclusively on other birds and bring practically all the popular ill-repute upon. the rest of the family. In addition to these, the Amer- ican goshawk, a Canadian species which enters the Northern States in winter, feeds largely on game and poultry ; and the rarer duck hawk, seldom seen far from the coast or larger waterways, feeds chiefly on waterfowl. Some authorities are inclined to mahitain that the smaller species, sparrow and pigeon hawks, may prove useful in towns and cities in destroying English sparrows. This is a good problem to assign, if some of these bii-ds are known to nest in the neighborhood, in the only case known to the author a pair of sparrow hawks which nested on one of the buildings of the Worcester Polytechnic Institute had finally to be shot on account of serious inroads upon the valuable bird life of the campus. Common types are : Marsh hawk — Circus liudsoulus. Sharp-shinned hawk — Accipiter relox. Cooper's hawk — Accipiter coopcrL American goshawk — Astur afrlcajnllus. Red-tailed hawk — Biiteo horedlis. Red-shouldered hawk — Buteo linedtus. Bald eagle — Haliceetus leucocephalus. Duck hawk — Fdlco peregrinus dnatum. Pigeon hawk — Fdlco cohimbdrlus. Sparrow^ hawk — Fdlco sparve'rhis. American osprey, or fish hawk — Pandion halidctus carolinentn's. Screech owl — Ottis dsio. Great horned owl — Bubo virginidnus. Order Cocq/ges (cocq/Xy "a cuckoo"). These are among our most valuable birds as destroyers of hairy caterpillars, and on 46 CIVIC BIOLOGY this account they should be universally protected. The order contains the cuckoos and kingfishers. Types are : Yellow-billed cuckoo — Coccyzus americdnus. Black-billed cuckoo — Coccyzus erytlirophthdlmus. Belted kingfisher — Ceryle dlcyon. This is an interesting bird, and we need not generally be- grudge it the minnows which it takes. About fish hatcher- ies and trout streams, how- ever, it is in general disfavor. Order Pici (picusy " a woodpecker ' ') . The wood- peckers are in general of great value as destroyers of orchard and forest in- sects. The sapsucker is generally considered an in jurious bird, and should be clearly distinguished from the valuable spe- cies which it resembles, and which may sometimes visit its sap holes. We should study the following common species: Hairy woodj)ecker — DrydOates villdsus. Downy woodpecker — Dryobates puhescens. Sapsucker — Sphyj-apicus vdrius. Red-headed woodpecker — Melane'rpes erythrocephalus. Flicker — Coldptes aurdtus. Order Macrochires (makrosy "long"; cheiry "hand"). The first three of the types given below are among our most valuable insectivorous birds, catching, as they do, both day- and night- flying insects. The humming bird feeds upon minute insects and spiders, and also largely upon the nectar of flowers and the sap of trees (from the holes of sapsuckers). It is most Fig. 21. Ruby-throat, nest and young Photograph by E. E. Evans METHODS OF BIRD STUDY 47 easily tamed, and may be fed on honey and water, half and half, with plant lice and spiders. All should be familiar with the : Whippoorwill — A ntrostomus vociferus. Nighthawk — Chordeiles virginidnus. Chimney swift — Chcetura peldgica. Ruby-throated humming bird — Archilochus cdlubris. Order Passeres {passer, " a sparrow ") — perching birds. In this largest order, which contains more than half the species to be studied, the family names will be of assistance in distinguish- mg the various groups. Family Tyrannidcs. — flycatchers. Types: Kingbird — Tyrdnnus tyrdnnus. Crested flycatcher — Myidrchus crinitus. Phcebe — Saydrnis phwbe. Wood pewee — Myidchanes virens. Least flycatcher — Empiddnax minimus. Almost the entire food of this group, as the name indicates, is insects, and stomach examinations have proved that the insects taken are mainly injurious. From the common habit of v^^atching from a conspicuous perch and flitting out to catch insects as they pass, the flycatchers are most interesting birds to study,espe- cially in ascertaining exactly hovr many insects a bird may catch within a given time, A laboratory period devoted to such work will instill a higher appreciation of the value of bird life than will any other lesson in the course. The only question as to the value of the group refers to the kingbird and its de- struction of the honeybees. While few bees have been found in its stomach, and it was therefore acquitted of serious injury, hundreds of crushed bees have since been discovered under its favorite perches, when Fig. 22. Chipping sparrow feeding young cowbird 48 CIVIC BIOLOGY these are near the hives. This is a good problem to have thoroughly worked up in any neighborhood in which bees are kept. Family AlaudidcR {alauda, "a lark ")— larks. Horned lark — Otdco- ris alpestn'a. For open fields and prairies this is a valuable bird, as it eats great quantities of weed seeds and insects. Family Corvidunish- luent decide whether the jay is good or bad for the locality. American crow — Cdrvus hrachyvhijnchos. The worst crime of the crow is also nest robbing. (I have known a pair to empty two robins' nests of seven young as a single, perhaps partial, breakfast.) Family /cter/^cE (icteros, "a yel- low bird ") — blackbirds, orioles, etc. Cowbird — Molothrus dter. This bird is a parasite and com- pels other species, generally warblers, vireos, and sparrows, smaller than itself, to brood and rear its young at the expense of their own. Cowbirds' eggs Fig. 23. Junco's nest in the aviary of Mr. Herbert Parker, Lancaster, Massachusetts should be removed from the nests of other birds whenever found. Bobolink — Dolichdnyx oryzivorus. In the N^orth this bird is appre- ciated as one of our most fascinating meadow songsters, if it is, not at the head of the list. In the South it is the destructive ricebird. Bronzed grackle — Quiscalus quiscula cfneus. Red-winged blackbird — Ageldius phceniceus. Meadow lark — Sturnella magna. Baltimore oriole — fcterus gdlhula. METHODS OF BIKD STUDY 49 Family Fringillidce, (fringilla, "a finch") — sparrows, finches. Types: Purple finch — Cnrpodacus purjnireus. American goldfinch — Astragalinus tristis. English sparrow — Passer domesticus. White-throated sparrow — Zonotrichia nlhico/lis. Tree sparrow — Spizella monticola. Chipping sparrow — Spizella passcrinn. Junco — Junco hyemdlis. Song sparrow — Melospiza melodUi. Fox sparrow — Passerella iliaca. Towhee, chewink — Pipilo ert/throphthdlnnis. Kose-breasted grosbeak — Zamelddia hidovicidmi. Indigo bunting — Passfrina cijdnea. The problems in this group are the valuable service rendered by all the sparrows in weed-seed destruction; and, also, the damage caused by the English sparrow. A single observation of the killing of a tree swallow or a bluebird by sparrows, or their eating the eggs from a rob- in's nest, is usually enough to convince a person of the advisal>ility of ridding the neighborhood of these pests. The year after all agree, the English sparrow may be banished from the continent into which it was so foolishly introduced in 1851. Until all agree, not much headway can be made against a species that has the })Ower to increase from a single pair to 275,716,983,698 in ten years. Family Tanagridtz — the tanagers. The scarlet tanager — Pirdnga eri/- thromflm. Why are not these beautiful ))irds more numerous in your locality ? Family Hirundinida — swallows and martins. Few more efficient, and certainly no more agTeeal)le, insect traps exist than the swallows. They should all be protected until they increase up to the limit of their insect food. The purple martin and tree swallow nest preferably in l)ird houses, and provision about barns should not be lacking for the cliff and barn swallows. Differences in nesting habits in species so closely related are of general interest. Types : Purple martin — Prdgne siibis. Cliff, or eaves, swallow — Petrochelidon lunifrons. Barn swallow — Hiriuido erythrogdstra. Tree swallow — Iridoprocne Inrolor. Bank swallow — Ripdria ripdria. 50 CIVIC BIOLOGY Family AmpelidcE (ampelus, "a vine") — waxwings. The cedar wax- wing, BombycUla ccdrdrum, known also as the cherry bird, is noted for destruction of cankerworms in our orchards. Family Laniidce (lanius, " butcher ") — shrikes. 'Ilie loggerhead shrike, Ldnius lu- davicidnus, frequents hedge- rows and borders of fields, where it feeds upon insects, field mice, and small birds. In cities it is said to be of some use in destroying Eng- lish sparrows. Study the prob- lem in your own locality. The number of our most valuable small birds — chickadees and wrens — which the shrike kills places it decidedly on the questionable list. Family Vireonidce. (vireo, " a greenfinch ") — the vireos or greenlets. These birds of the terminal foliage and pen- sile nests are among the best of our orchard and roadside insect police. We may certainly make the acquaintance of at least three of the seven common species. Red-eyed vireo — Vireosylva oUudcea. Warbling vireo — Vireosylva gilva. Yellow-throated vireo — Lanivireo Jldcifrons. Family Mniotiltida (mnion, "moss"; tiltos, "pulled out") — warblers. To make the first acquaintance with this interesting and difficult family we may begin with four of the common resident species. Black-and-white warbler — Mniotilta vdria. Yellow warbler — Dendroica cestiva. Ovenbird — Scurus aurocapillus. American redstart — Setdphaga ruticilla. Family Troglodytida {troglodyta, "cave dweller") — thrashers, wrens, etc. Mocking bird — Mimus polygldttos. This offers the problem of a rare Fig. 24. Kemains of chickadee killed by a shrike Photograph by the author METHODS OF BIRD STUDY 51 bird for our district, and one which is becoming rarer year by year. The reason is largely that specimens are desired for collections. Hence rec- ords commonly read : " Remarkable instance of a pair of mocking birds nesting in central Massachusetts. On June 8 both parents with nest and clutch of six eggs were collected and are now in . . ." etc. The mocking bird is often described as the most remarkable bird musician in the world, and we could certainly not do less than encourage it to breed as far north as possible. Catbird — Dumetdlla carolinensis. Brown thrasher — Toxdstoma rufum. Both of these birds are valuable to control insects of garden and orchard, and, besides, are among our best musicians. House wren — Troglodytes aedon. Every garden should be well stocked with this tireless insect destroyer. Marsh wren, short-billed — Cistothorus stelldris. Compare with house wren for habitat, foods, nests. Family Certhiidoi — creepers. Brown creeper — Certhia familidris ameri- cdna. One of our winter birds that should be generally known and pro- tected. Family Paridcs — nuthatches and titmice. White-breasted nuthatch — Sitta carolinensis. Chickadee — Pentliestes atricapillus. All are agreed that the chickadee is one of the most useful birds in freeing orchards of all sorts of insect pests, from cankerworms to aj)hides. Family Sylviida — kinglets, gnat catchers, etc. The ruby-crowned king- let — Regulus sdtrapa. Family Turdidts 125,000 2-8 Roots 50.000 .3-8 Seeds 5-10 Hoots 115,522 4-0 Kootstock 250,000 3-7 Leaves 5.000 2^-5 Flowers 25-75 Leaves and tops .30,000 3-0 Leaves and tops 125,000 .3-8 Leaves 100,000-150,000 21-8 Seeds 10,000 3-7 Seeds 20,000 3 • Leaves 10,000-20,000 4 Seeds 5,302,876 3-0 While the demand for medicinal Aveeds is not great, market- ing those that have useful properties would tend to check their spread, and might, in turn, pay at least for their removal. Other native drug plants. Clearing of the forests and the work of the drug collector have resulted in almost extermi- nating many of our native drug plants. To save these the Bureau of Plant Industry has undertaken the work of domes- ticating them with the hope not only of supplying the home market but also of exporting them. In the gardens at Washington some success in an experi- mental way has been attained in raising goldenseal, cascara 1 Compiled from Bulletin No. 188, United States Department of Agricul- ture, "Weeds used in Medicine." This gives prices and methods of pre- paring for market. PLANT PROBLEMS 73 sagrada, Seneca siiakeroot, and purple cornflower. Ginseng has already been domesticated, the total yield hi states east of the Mississippi River being about one million dollars annually. A considerable portion of crude drugs used in the United States is of foreign origin. To supply the home market and save millions of dollars now spent on foreign drugs, the Bureau has interested itself in the experimental culture of these foreign plants in soil and climate similar to their own. Plots of Asiatic poppy, camphor trees, cinchona, belladonna, foxglove, and red peppers have been planted in suitable parts of our country. Poisonous plants. Certain plants are poisonous either when handled or eaten. For lack of statistics, no estimate can be given as to the amount of damage done by them. Complaints have been so numerous against various plants which poison man and animals, that the Government has investigated them and has issued a number of bulletins on poisonous plants of the United States.^ (See Bulhthi 86^ " Thirty Poisonous Plants.") Of the thirty plants described, about one third are weeds ; the others are fungi, lierbs, shrubs, and trees. The most poisonous plants are mushrooms (Amanita mi(scaria and Ama- nita phalloides)^ the various species of water hemlock (^Oieiita^, and the loco weed (Astragalus). Damage to the live-stock business from loco weed is enormous. Colorado, in a vain attempt to exterminate it, spent $200,000 in bounties between the years 1881 and 1895. 1 Bulletins from United States Bepartment of Agriculture : 28. W^eeds and how to Kill them. 86. Thirty Poisonous Plants. 188. Weeds used in Medicine. 279. Methods of eradicating Johnson Grass. Besides these, almost every state issues complete and fully illustrated bul- letins on its own weeds. Canada issues weed bulletins on an elaborate scale. 74 CIVIC BIOLOGY Much suffering is caused by poison ivy, the active poison being a nonvolatile oil found in all parts of the plant — even the dried wood. The oil is soluble in alcohol and may be removed from the skin by thoroughly bathing exposed parts in alcohol and then washing off with water. An alcoholic Fig. 34. Purple or woolly loco weed — Astragalus moUissimus Photograph by C. Dwight Marsh, United States Department of Agriculture, Bulletin 112 solution of sugar of lead (lead acetate) destroys the oil. The same remedy applies to poison sumac and poison oak. Additional Studies 1. Prepare a list of common weeds found along the roadside, rail- roads, in grass, field, backyard, and garden. 2. Compare number of seeds borne by a weed with those of a wheat, oat, or barley plant. 3. What weeds do you know that are eaten as vegetables ? 4. How is the fact that weeds are not valuable food for domestic animals to their advantage ? PLANT PROBLEMS 75 5. Discuss the advisability of having foreign seeds and grains in- spected before being allowed to enter this country. 6. Discuss the advantage of smothering weeds with quick-growing, thickly seeded crops, like red clover an^ rye. 7. Test the germinating power of a weed by placing its seeds on damp blotting paper between two plates. 8. Record instances observed of weeds damaging food plants. What did Darwin mean by the " struggle for existence " and " survival of the fittest " ? (Ref . : Hodge, " Nature Study and Life," chap, vii.) Copy the following list of poisonous plants into your notebook, and make the acquaintance of each one, if possible, during outdoor tramps. Increase the list by wider observation. Poison ivy — Rhus radicans [poison oak, three-leaved ivy, mercury, black mercury, markweed, pikry (Maine)]. Poison sumac — Rhus vernix [swamp sumac, dogwood (Massachu- setts), poison elder (Alabama), poison ash (Vermont), thunderwood (Georgia, Virginia)]. Poison oak — Rhus diversiloba [poison ivy, yeara, California poison sumac]. Poison hemlock — Conium maculatum [hemlock, wild hemlock, spotted parsley, stinkweed, poison root, poison snakeweed, cashes, wode-whistle]. Water hemlock — Cicuta maculata [spotted parsley, snakeweed, beaver poison, musquash root, muskrat weed, cowbane, spotted cowbane, chil- dren's-bane, death-of-man]. Pokeweed — Phytolacca decandra. Corn cockle — Agrostemma githago. Black cherry — Prunus serotina [wild cherry, rum cherry]. Red buckeye and common horse-chestnut — A^sculus pavia and hippocastanum. Broad-leaf laurel — Kalmia latifoUa [laurel (north of Maryland), ivy (south of Maryland), mountain laurel, sheep laurel, poison laurel, wood laurel, small laurel, high laurel, American laurel, poison ivy, ivy bush, ivy wood, big ivy, calico bush, spoonwood, kalmia, wicky]. Narrow-leaf laurel — Kalmia angustifolia [sheep laurel, lambkill, sheep poison, lamb laurel, small laurel, low laurel, dwarf laurel, wicky]. Jimson weed — Datura stramonium and D. tatula, the taller and purple-flowered species [Jamestown weed, common stramonium, thorn apple, apple of Peru, devil's apple, stinkwort, stinkweed, Jamestown lily, white man's plant (by the Indians)]. 76 . CIVIC BIOLOGY Caper spurge — Eupliorhia lathyris [garden spurge, mole plaut, gopher plant, wolf's-milk, springwort]. Snow-on-tlie-mountain — Euphorbia ihuryinata. Other poisonous plants are : Death-cup mushrooms, of the genus Amanita. American false hellebore — Veratrum viride [white hellebore, swamp hellebore, Indian poke, pokeroot, Indian uncus, crow poison, devil's-bite, duck-re tter, itchweed, bugbane, wolfsbane, bear corn]. Dwarf larkspur — Delphinium tricorne [staggerweed (Ohio) un c O to C s ^ ) ^ rt CD aj .^^^- ) ^I ■'-' ^ -"^ d.H « _r 03 - 0) i >-, a> be - I >< 33 ' I O M * -^s bcTI 13-^^ M' c r= g -ij as S ^ +^ t- S -G (13 ?^ ? "^ 5 '^ S* !=ti I -I' -2 I ^ S g tH 03 S ^ ■I «> ^ £« J'l' 03 S si ^ t~ s s 5 s I i I i - 1 f5 8 2 ^ .S c S <5 il O =15 'ilS HOME PLA>s^TING AND LANDSCAPE GAEDENING 83 trees; measure distances apart and draw the ground plan to scale, and sketch or photograph the groups. Rules for grouping trees are sometimes given. The follow- ing are modified from different authorities as suggestive and practical. 1. Specimen trees — those which stand alone — should be chosen for special beauty or character ; oaks, chestnuts, black Fig. 38. A specimen of nature's planting walnuts, old pines, and cedars for massive strength and dig- nity; hemlock, elm, larch, and spruce and the birches for graceful tracery of form and outline ; Colorado blue spruce, purple beech, Schwedler, swamp and Japanese maples for rich coloring. 2. Groups should not be too compact, and on estates of limited extent are generally more effective if made up of trees of different characters. They should he unsymmetrical, irreg- ular, " natural " in form. The taller trees should, of course, occupy the center, or form the background in boundary-line 84 CIVIC BIOLOGY groups. There is opportunity here for fine contrasts in form, color, and character — oak and weeping willow or American elm, birches against white pine, etc. 3. Plant trees or groups to screen objectionable features of the landscape, and leave open spaces toward all pleasing views. 4. Plant deciduous trees on the south and west of the house for summer shade and winter sunshine, and evergreens along the northerly side to serve as stormbreaks in winter. Shrubs. Given the bounds and main features in tastefully planted trees, the shrubbery lets the picture down naturally to the ground, and supplies much desired color and fragrance. Shrubs, too, more than anything else form the setting for the* house, fit it to the eartli, and make it a part of the landscape. The house being the center of the general scheme, we should place the choicest shrubs nearest to it. For outdoor laboratory work study throughout the fall and spring, at least, good specimens of all the different ornamental shrubs to be found in your local parks or neighborhood. Observe them in all possible relations to trees, buildings, and other shrubs, so that you will be able to choose the shrubbery of a park or the home grounds with intelligent taste. A local planting table like that suggested for the trees should be made, giving size, form, preferred exposure, and color and season of bloom. A selection of shrubs may be made which will furnish bloom for cutting and fine color effects in either flower or fruit for not only the growing season but the entire year. If it is desired to combine use and ornament, — a tendency growmg in favor, — nothing in the way of shrubber}' can be more effective, either in bloom or fruit, than the dwarf fruit trees, especially peach, apricot, nectarine, cherry, pear, and apple. Lists and descriptions of desirable shrubs for the locality can be obtained from any good nursery catalogue. '' American trees and shrubs for American homes " is a rule with exceptions, but one that has much good sense in its favor. Fk;. 81), Mission iijrape. Larijest grapevine in the world Planted in 1842, in 1895 bore over ten tons of grapes, Carpinteria, California Fig. 40. Delaware grape Living decoration for a dining porch 85 86 CIVIC BIOLOGY What exotic is more beautiful than our mountain laurel or our rhodora, or more graceful than our sumacs and elder- berry, or sweeter than our pepper bush and wild rose? It is no slight matter that a plant has become adjusted to its environment on a large continent through the many centu- ries of its struggle for existence. Flowers. With slu-ubbery now as the background come naturally, in the finest landscape effects, the hardy perennials Fig. 41. The most beautiful back door in Worcester, Massachusetts Fig. 42. An ugly back door Compare with Fig. 41 — peonies, lilies, irises, hollyhocks and phloxes, goldenrods and asters, and a host of others; also the annual bedding plants, the cannas and dahlias, sunflowers, marigolds and zinnias, nasturtiums, sweet peas and flowering beans, and by all means, here and there, a few tuberoses and a bed of helio- trope and mignonette. These supply the finishing touches for both color and fragrance, and should be studied largely as a matter of individual preference and taste. Here is the test, however, for harmonious and pleasing effects in color, and, since we must live with our homes so much of the time, the HOME PLANTING AND LANDSCAPE GAEDENING 87 whole effect should be restful and comfortable and as far removed from fussiness as possible. Vines. Especially on the house and buildings, vines add a touch of comfort, as well as wildness and grace, without which few pieces of landscape gardening are complete. Vines of all plants are also the most plastic, convenient, and ac- commodating. With them we may have shade of any degree anywhere we wisli, cover anything, from a snag, post, or rock to a factory wall, and we may have fra- grance and flowers and even fruit thrown in for good measure. As suggested for the trees and shrubs, make a special study of all the vines adapted for home and park planting in your locality, and include meth- ods of propagating and cul- ture of each. The world over, the grape combines in highest degree all the best qualities of both use and beauty. The way our American wild grapes climb the tallest forest trees shows that with proper support they may be carried to any reason- able height. A growth of sixty-three feet of vine from a single bud in a season proves how quickly any extent of wall can be shielded from the hot sun of summer by prop- erly trained grapevines. For covering surface no other vine, Fig. 43. California grapes Photograph by George C. Husmann, United States Department of Agriculture 88 CIVIC BIOLOGY excepting possibly the Actinidia, can compare with the grape, if well established. The fact that it climbs by tendrils makes it much easier to train, prune, and control than vines which twine around their supports. The grape thrives in poor soil, wet or dry, and can be depended upon to flower and fruit for centuries, renewing its youth often from the root. Varieties differ much in form and size of leaf and in vigor and rapidity of growth. Make a special study, with sketch to scale, of at least one good specimen vine before it is pruned back in the fall. Note variety, age, size, and height of main stem and length of several of the most vig- orous canes of the season's growth. Record, if possible, the amount of fruit pro- duced. By each member of the class selecting a differ- ent variety, the grapes best suited to the locality may be compared and learned. Houses, even in crowded cities, might be transformed into bowers of shade and beauty by the adequate use of the grape alone. Aetinidia arguta is a close second of the grape. After be- coming well established it is a most, rampant grower, speedily reaching the tops of the tallest trees, and about buildings is likely to require severe pruning. The leaves are clean and glossy, with red petioles. Fragrant and attractive flowers appear in June, and the fruit ripens in September and October. This is a dull green drupe the size of a small plum, with a flavor and quality quite unlike anything American. The Aeti- nidia comes to us from Japan and is hardy and well adapted to our climate. Along with other valuable importations from Fig. 44. Flowers of Aetinidia HOME PLANTING AND LANDSCAPE GARDENING 89 the same source it has the advantage of not being attacked by American insect pests. Rom rugosa^ the Japanese quince, and the Japanese snowball are other cases in point. Following are some problems in landscape gardening : 1. Make a series of sketches, to scale, of your home grounds, — ground plan and at least one view, — naming and locating all trees, sln-ubs, vines, and bedduig plots with their contents. 2. Draw a ground plan and view of your home grounds as you Avould wish to have them. 8. Can you suggest any improvements in the street tree planting of your town, city, or neighborhood ? Draw plans and specifications for special local prob- lems of this kind — the treatment of certain streets or roadsides. 4. Let each member of the class sketch a ground plan and view Fig. 45. Actinidia arguta Two vines, three years from transplanting, afford dense shade for a porch of the school grounds, giving both specifications and cost. 5. Taking a local public square, park, common, or play- ground as a special problem for analysis and study, can you suggest improvements in its planting ? The simplest principles of landscape gardening are often alluded to as the " ^, B, C " of the subject. They are based upon the pleasing arrangement of trees, vines, and shrubs and 90 CIVIC BIOLOGY open glades as found in beautiful bits of natural woodland. A. Leave open glades for air and sunshine. They make even modest grounds seem roomy. B. Plant in masses, like the forms of clouds, leaving open vistas toward sunrise and sun- set and all pleasing views, and covering unsightly features of the landscape. C. Avoid straight rows ; Nature never plants that way. Finally we may study home and city planting as an invest- ment. If well done, probably no equal expenditure will re- sult in larger returns. Figure out increased value of property along well-planted streets and in the vicinity of public parks. Let each member of the class study and analyze his own home with this point in view — figuring into the account iirst cost, yearly expenditures, and upkeep against enhanced values. A shade tree in the wrong place may be a positive injury to a home, while the same tree in tlie right place might enhance its value a hundred, or even a thousand, dollars. And in these, as in all similar cases, it is not the money values we are studying so much as the human health and comfort which they represent. The planning and planting of a home or a country beauti- ful enough to inspire the love of a people is no unimportant matter. Compare Russia and Japan with this feature in view and in connection with the results of the recent war. '^-B Fig. 46. Adinidia arguta in fruit CHAPTER IX PRACTICAL BIOLOGY OF AGRICULTURAL PRODUCTION AND CIVIC UTILIZATION OF LAND Public prosperity is like a tree : agriculture is its roots ; industry and com- merce are its branches and leaves. If the root suffers, the leaves fall, the branches break, and the tree dies. — Chinese saying, from Hopkins, ''Soil Fertility and Permanent Agriculture " In final analysis civilizations rest mainly upon agricultural efficiency. At least, this must be increasingly true as civiliza- tion advances. In this vital matter it is high time to cast aside all pride and conceit and wake up to a sense of our low agricultural efficiency as a people. In 1907 a total of 20,000 square miles of agricultural land in Japan supported 46,977,003 people, or 2349 people to the square mile, with less than one dollar per capita excess of agricultural imports over exports. Fertile regions of both China and Japan sup- port as high as 3840 people per square mile. Compare these figures with those for Belgium, the most densely populated country in Europe ; here less than 300 people per square mile are supported. The best farming districts of the LTnited States support about 30 people per square mile. Further, in little more than a brief century we have swept over a continent rich in the accumulated fertility of many thousands of years, and in ignorance have wasted and depleted (" mined " rather than " cultivated ") the soil. As land in one region has been mined out, we have abandoned it and moved to virgin fields, but now, with practically no more new land available, we are forced to turn toward the more civilizing and socially ethical task of permanent American agriculture. 91 ujmuiu^mMUMmmM^^i^jMJM^^ THE EFFECT OF THOROUGH CULTIVATION UPON THE FARMER'S OWN MIND. AND IN REACTIONTHROUGH HIS MIND BACK UPON HIS BUSI- NESS, IS PERHAPS QUITE EQUALTO ANY OTHER OF ITS EFFECTS. EVERY MAN IS PROUD OF WHAT HE DOES WELL, AND NO MAN IS PROUD OF THAT HE DOES NOT WELL. WITH THE FORMER HIS HEART IS IN HIS WORK, AND HE WILL DO TWICE AS MUCH OFIT WITH LESS FATIGUE ; THE LAT- TER HE PERFORMS A LITTLE IMPERFECTLY. LOOKS AT IT IN DISGUST, TURNS FROM IT, AND IMAGINES HIMSELF EXCEEDINGLY TIRED -THE LITTLE HE HAS DONE COMES TO NOTHING FOR WANT OF FINISHING. HAVE SO FAR STATED THE OPPOSITE THEORIES OF "MUD- SILL" AND "FREE LABOR," WITHOUT DECLARING ANY PREFER- ENCE OF MY OWN BETWEEN THEM. ON AN OCCASION LIKE THIS, I OUGHT NOT TO DECLARE ANY. I SUPPOSE, HOWEVER, I SHALL NOT BE MISTAKEN IN ASSUMING AS A FACT THAT THE PEOPLE OF WISCONSIN PREFER FREE LABOR, WITH ITS NATURAL COMPANION, EDUCATION. THIS LEADS TO THE FURTHER REFLECTION THAT NO OTHER HUMAN OCCUPATION OPENS SO WIDE A FIELD FOR THE PROFITABLE AND AGREEABLE COMBINATION OF LABOR WITH CULTIVATED THOUGHT, AS AGRICULTURE. I KNOW NOTHING SO PLEASANT TO THE MIND AS THE DISCOVERY OF ANYTHING THAT IS AT ONCE NEW AND VALUABLE - NOTHING THAT SO LIGHTENS AND SWEETENS TOIL AS THE HOPEFUL PURSUIT OF SUCH DISCOVERY. AND HOW VAST AND HOW VARIED A FIELD IS AGRICULTURE FOR SUCH DISCOVERY! THE MIND, ALREADY TRAINED TO THOUGHT IN THE COUNTRY SCHOOL, OR HIGHER SCHOOL, CANNOT FAIL TO FIND THERE AN EXHAUSTLESS SOURCE OF ENJOYMENT. EVERY BLADE OF GRASS IS A STUDY ; AND TO PRODUCE TWO WHERE THERE WAS BUT ONE IS BOTH A PROFIT AND A PLEASURE. AND NOT GRASS ALONE, BUT SOILS, SEEDS, AND SEASONS - HEDGES, DITCHES, AND FENCES -DRAINING, DROUGHTS. AND IRRIGATION - PLOWING, HOEING, AND HARROWING- REAPING, MOWING AND THRESHING - SAVING CROPS, PESTS OF CROPS, DISEASES OF CROPS, AND WHAT WILL PREVENT OR CURE THEM - IMPLEMENTS, UTENSILS. AND MACHINES, THEIR RELATIVE MERITS, AND HOW TO IMPRO.VETHEM - HOGS, HORSES, AND CATTLE - SHEEP, GOATS, AND POULTRY -TREES, SHRUBS, FRUITS, PLANTS, AND FLOWERS - THE THOUSAND THINGS OF WHICH THESE ARE SPECIMENS - EACH A WORLD OF STUDY IN ITSELF. IN ALL THIS, BOOK LEARNING IS AVAILABLE. A CAPACITY AND TASTE FOR READING GIVES ACCESS TO WHATEVER HAS ALREADY BEEN DISCOVERED BY OTHERS. IT IS THE KEY. OR ONE OF THE KEYS, TO THE ALREADY SOLVED PROBLEMS. AND NOT ONLY SO : IT GIVES A RELISH AND FACILITY FOR SUC- CESSFULLY PURSUING THE UNSOLVED ONES. THE RUDIMENTS OF SCIENCE ARE AVAILABLE. AND HIGHLY AVAILABLE. SOME KNOWLEDGE OF BOTANY ASSISTS IN DEALING WITH THE VEGETABLE WORLD -WITH ALL GROWING CROPS. CHEMISTRY ASSISTS iN THE ANALYSIS OF SOILS, SELECTION AND APPLICATION OF MANURES, AND IN NUMEROUS OTHER WAYS. THE MECHANICAL BRANCHES OF NATU- RAL PHILOSOPHY ARE READY TO HELP IN ALMOST EVERYTHING, BUT ESPECIALLY IN REFERENCE TO IMPLEMENTS AND MACHINERY. THETHOUGHT RECURS THAT EDUCATION - CULTIVATED THOUGHT- CAN BEST BE COMBINED WITH AGRICULTURAL LABOR, OR ANY LABOR, ON THE PRINCIPLE OF THOROUGH WORK ; THAT CARELESS, HALF PERFORMED, SLOVENLY WORK MAKES NO PLACE FOR SUCH COMBINATION; AND THOROUGH WORK, AGAIN. RENDERS SUFFICIENT THE SMALLEST QUANTITY OF GROUND TO EACH MAN; AND THIS, AGAIN. CONFORMS TO WHAT MUST OCCUR IN A WORLD LESS INCLINED TO WARS AND MORE DEVOTED TO THE ARTS OF PEACE THAN HERETOFORE. POPULATION MUST INCREASE RAPIDLY. MORE RAPIDLY TH\N IN FORMER TIMES, AND ERE LONG THE MOST VALUABLE OF ALL ARTS WILL BE THE ART OF DERIVING A COMFORTABLE SUBSISTENCE FROM THE SMALLEST AREA OF SOIL. NO COM- MUNITY WHOSE EVERY MEMBER POSSESSES THIS ART, CAN EVER BE THE VICTIM OF OPPRESSION IN ANY OF ITS FORMS. SUCH A COMMUNITY WILL BE ALIKE INDEPENDENT OF CROWNED KINGS, MONEY KINGS, AND LAND KINGS. IT IS SAID AN EASTERN MONARCH ONCE CHARGED HIS WISE MEN TO INVENT HIM A SENTENCE TO EE EVER IN VIEW, AND WHICH SHOULD BE TRUE AND APPROPRIATE IN ALL TIMES AND SITUATIONS. THEY PRESENTED HIM THE WORDS. "AND THIS. TOO, SHALL PASS AWAY." HOW MUCH IT EX- PRESSES! HOW CHASTENING IN THE HOUR OF PRIDE! HOW CONSOLING IN THE DEPTHS OF AFFLIC- TION! "AND THIS, TOO, SHALL PASS AWAY." AND YET, LET US HOPE, IT IS NOT QUITE TRUE. LET E'~n US HOPE, RATHER, THAT BY THE BEST CULTIVATION OF THE PHYSICAL WORLD BENEATH AND AROUND ^ US, AND THE INTELLECTUAL AND MORAL WORLD WITHIN US, WE SHALL SECURE AN INDIVIDUAL. SO- §{ CIAL, AND POLITICAL PROSPERITY AND HAPPINESS. WHOSE COURSE SHALL BE ONWARD AND UPWARD, 1^ AND WHICH. WHILE THE EARTH ENDURES. SHALL NOT PASS AWAY. -ANNUAL ADDRESS BEFORE THE S WISCONSIN STATE AGRICULTURAL SOCIETY, AT MILWAUKEE. WISCONSIN. SEPTEMBER 30, 1859. ^ ABRAHAM LINCOLN, "COMPLETE WORKS," VOL.1, P. 579 FF. I i % I I I i 92 BIOLOGY OF AGRICULTURAL PRODUCTION 93 Agricultural efficiency. Wherever possible let each member of the class choose some local plant or anunal industry and collect records, establish working standards, and figure out the local percentage of efficiency. This might well form the main thesis work of the year, and, in a connnunity in which agricul- ture is important, by distributing theses to cover the different crops we may make this work contribute to civic advancement. A recent estimate by Emerson yields the following results : SrANDAUDS AND Percentagp: of Efficiency von Following Chops Standard Yield AVEKAOK PeuCentof Annual Loss bv PKR ACKK Yield Efficiexcy Low Efficiexcv Potatoes 500 bu. 96 bu. 19 $900,000,000 Wheat 50 bu. 14 bu. 28 1,000,000,000 Cotton 1 bale 0.35 bale 35 1,000,000,000 Corn ^ lOObu. (record 239 bu.) 28 bu. 28 2,680,000,000 Oats 1 100 bu. (record 209^ bu.) 32 bu. 32 585,413,000 The standard of 500 bushels of potatoes per acre is ad- mittedly low. l^y the mere addition of brains ('' cultivated thought ") U) breeding and selection of variety, and scientific precision in fertilizers and culture methods, this standard might be raised to 1000 bushels, possibly, without increasing per-acre cost of operation, except to pick up the additional 500 bushels. Probably Lord Rosebery holds the world's record : 2053 bushels of potatoes — 1754 marketable and 299 bushels of culls per acre. AVith the standard at 2000 bushels our scale of efficiency falls to 4 1 per cent. Hills of potatoes vary remarkably in the same field, and beginnings have been made in *' hill selection " of seed on this account. Tubers planted from strong hills have thus been found to yield as high as sixteen times as many pounds as 1 Data obtained elsewhere. 94 CIVIC BIOLOGY tubers from weak hills of the same variety. Little, however, has been done by way of recording the yields of single hills. Grubb gives 16 tubers, weighing 8 pounds, as the ideal hill in field culture. Perry Nathan Pickett, aged twelve years, in connection with his industrial project work in Salem, Ore- gon, in 1914, produced a rec- ord hill of Burbank potatoes, containing 1 3 large and 2 small tubers, weighing l6 pounds. A record hill from Lexington, Oregon, yielded 24 pounds, and Carl Gabrielson, aged eleven, Puyallup, Washing- ton, has reported a volunteer hill in his school garden that dug 103 potatoes, rang- ing from 12 ounces to the size of a hen's egg and weighing 40 pounds 12 ounces. If we know how to raise one hill best, we may extend this knowledge to any number of hills. Hence, for an ele- mentary standard unit the single plant will be a more usable one than the plot or acre. Any boy can find a place to raise one or ten hills of potatoes ; he may try a different experiment on each hill, and thus learn more from a single hill than he might from an acre. The same is true of a single plant of wheat, corn, tomato, cabbage, lettuce, strawberry, blackberry, raspberry, grape, peach, apple, pear, rose, lily, or anything else. Fig. 47. Growth race between potatoes Potatoes weighed 186.7 and 9.8 g. At eud of fifty-eight days the roots had growu 8640 ft. and 155 ft. respectively. Photo- graph by Frances W. Tufts BIOLOGY OF AGEICULTUEAL PRODUCTION 95 It is interesting that Lincoln should state the problem so clearly, more than fifty years ago.^ My first suggestion is an inquiry as to the effect of greater thorough- ness in all departments of agriculture than now prevails in the North- west— j)erhaj)s I might say in America. To sj^eak entirely within bounds, it is known that fifty bushels of wheat, or one hundred bushels of Indian corn, can be produced from an acre. Less than a year ago I saw it stated that a man, by extraordinary care and labor, had produced of wheat what was equal to two hundred bushels from an acre. But take fifty of wheat, and one hundred of corn, to be the possibility, and compare it with the actual crops of the country. ]\Iany years ago I saw it stated, in a patent-office report, that eighteen bushels was the average crop throughout the United States ; and this year an intelligent farmer of Illinois assured me that he did not believe that the land harvested in that State this season had yielded more than an average of eight bushels to the acre; much was cut and then abandoned as not worth threshing, and much was abandoned as not worth cutting. As to Indian corn, and indeed, most other crops, the case has not been much better. For the last four years I do not believe the ground planted with corn in Illinois has produced an average of twenty bushels to the acre. Lincoln admits too much for the sake of argument, however, when he says : Unquestionably it will take more labor to produce fifty bushels from an acre than it will to produce ten bushels from the same acre ; but will it take more labor to produce fifty bushels from one acre than from five? Unquestionably thorough cultivation will require more labor to the acre ; but will it require more to the bushel ? Recent experiments have proved that less labor, rather than more, may produce the larger crop. Goethe's proverb, Nichts ist schrecklicher als tdtige Unwissenheit, " Nothing is more ter- rible than active ignorance," applies with unusual force to the delicate task of raising a plant best. The most laborious and expensive factor in growing a field of corn has been "thorough cultivation." After this had been 1 Abraham Lincoln, Complete Works, Vol. I, p. 577. 96 CIVIC BIOLOGY tearing off half the roots of the corn plants for centuries, and laboriously reducing the yields from 30 to 50 or more busliels per acre, some one hit upon the idea of studyhig — applying '' cultivated thought " to the roots of the shigle corn plant. It was discovered that many of them spread out near the surface, five, six, or even seven feet in every direction. Next came the thought, May not too deep cultivating injure these roots ? The experhnent has now been tried of shaving tlie weeds without stirring the soil at all, applying careful Fig. 48. Two plots of corn on peaty swamp land Left, fertilized with phosphorus (not needed) ; crop, 0. Right, fertilized with potassium; crop, 72 hushels per acre. Seed, cost of fertilizer, aud labor on the two plots about equal. Photograph by Cyril G. Hopkins shallow tillage to comparable rows in the same fields. Results have shown, on the average, equal yields from the uncultivated rows. Figure out, for your farm, township, county, state, or for the United States, how many dollars' worth of labor this one discovery may save annually. Pure-bred selected strains. Again, we have learned that by breeding and selection of productive strains the crop may be increased without additional labor. This fact gives the added value to pure-bred stock in animals and plants. Half the plants in an ordinary field of potatoes or corn may be ''loafers"; half the trees in an ordinary orchard may be " resters " ; half the BIOLOGY OF AGRICULTURAL PR0I>UCT10N 97. hens or cows in the ordinary barnyard may be '' boarders.*' A single specimen of plant or animal may produce a phenomenal yield, but the progeny may revert to loafers and boarders. Pure-bred strains have been carefully selected for generations, until all bad heredity has been weeded out and the progeny can be relied upon to be thoroughbreds, that is, to yield a uniform, standard result. Collect records of various pure-bred strains in the neighborhood and compare yields, as below : DiFFERENCKS IN YiELD DuE TO YaUIETY, EXPERIMENT STATION, RosTERN, Canada Yield Weight Time to Unmarket- I'EB Acre PER Bushel Mature able Huron wheat 73 bu. 59 lb. 107 days Marquis wheat .... 70 bu. 61 11). 98 days Kubanka wheat .... 37 bu. 52 11). 107 days Reeves' Rose potato . . 623 bu. 46 bu. American Wonder potato 371 bu. 58 bu. Disease-resisting strains. A^ariation applies to immunity from disease as well as to any other character, and hence the Avorld is bemg searched for strains of animals and plants which have developed resistance to prevailing diseases. Cattle from India are being introduced into the south, because they are immune to Texas fever. The ordinary Crimson Rambler rose is much infested with mildew, while Van Fleet's seedhng is practically immune to it. Such innnunity may extend even to freedom from insects, as sliown by many foreign introductions, notably Bosa rugosa and the floAvering quince and snowball from Japan. Thus in all sorts of epidemics it is of great im- portance to note any immune individuals, and these should be carefully preserved with a view to development of resistant strains. Collect the data on any local work along this line. A good case in point occurred recently in the cabbage industry of southeastern Wisconsin. A fungus suddenly appeared w^hich took 98 CIVIC BIOLOGY practically the entire crop. The Agricultural Department at Madison was appealed to for help, and the experts, on visiting the infested terri- tory, found here and there a cabbage plant that had not been attacked. Seed was saved from these specimens and a resistant strain secured. Another example is the resistance of mazzard stock to cherry gummosis. Problem of soil fertility. Fifteen chemical elements com- monly enter into or constitute the plant body. They are natu- rally the most abundant elements of air, water, and earth. Take, for example, the composition of corn : Per Cent Oxygen . , 46.000^ Carbon . . 45.000 ► Hydrogen . 6.400^ Nitrogen . 1.760^ Phosphorus .300 - Potassium . .340 J Magnesium .125' Calcium .022 Iron . . . .008 Sulfur . . .004 Silicon . .014 ■ Sodium . . .013 Chlorin . . .013 Aluminium Manganese Total . 99.99 1 Elements obtained in abundance from air and water. Elements that the corn plant must get from the soil, and that we must buy if they are deficient. Elements seldom lacking in the soil in the small amounts required, except calcium, which in regions free from limestone is often added to " sweeten," or correct acid- ity in, soils. An acre of soil 6J inches deep weighs 2,000,000 pounds, and if we analyze this and determine how many pounds of the necessary elements it contains, and if we know how many pounds of these elements are removed in a given crop, we can figure roughly how long the soil will '' last," that is, be able to produce the crop. Hopkins has done this in the table on the following page.^ ■^ Of. Hopkins, Soil Fertility and Permanent Agriculture, p. 13. 2 Ibid., p. 59. BIOLOGY OF AGRICULTURAL PRODUCTION 99 Relative "Supply and Demand" of Seven Elements Essential Plant-Food Elements Pounds in 2,000,000 Pounds of Aver- age Soil Pounds IN 100 Bushels of Corn Years Sup- ply WILL last Phosphorus Potassium Magnesium Calcium " . Iron Sulfur "... 2,200 49,200 48,000 68,800 88,600 2,200 17 19 7 n 130 2,600 7,000 55,000 200,000 10,000 Nitrogen (virgin N.W. soil)i . Nitrogen (in air over acre) i . 6,936 70,000,000 ' 69 100 , 700,000 Of course the problem is not as simple as this table would indicate, because these elements are being returned to the soil in various ways from the air and from the decay of plants and from animal wastes. The table does show what tends to happen in the ordinary process of deple- tion from continuous cropping, if care is not taken to thus return the needed elements to the soil. The three absolutely essential elements which are likely to limit productivity of a soil are nitrogen, phosphorus, and po- tassium. Nitrogen, the most vital of all, does not exist in combination as a mineral in the soil, but must be added from the decay and waste matters of animals and plants or by bac- terial action. Of the other two, phosphorus is likely to be the limiting element, but potassium compounds, as well as those of calcium, are so easily soluble that they are likly to be completely leached away, as was the case in the peaty loam soil (Fig. 48). No matter what the abundance of the others, lack of any essential element limits plant growth ; it is like a storehouse full of food, with the key lost. This is well shown in the Maryland Experiments with Lime.^ 1 Added to table from p. 559. 2 Cf . Hopkins, Soil Fertility and Permanent Agriculture, p. 167. 100 CIVIC BIOLOGY Produce in Eleven Years, per Acre Bushels of Corn IN Four Crops Bushels of Wheat IN Three Crops Tons OF Hay IN Four Crops No lime Ground shells (2500 lb.) 98 145 32 43 2.60 4.29 Learn the results of local experiments in fertilizing land and collect all available records and data on local soil analyses and surveys. The possible value of sucli work is well demon- strated in the following from the Oswego Experiments with strawberries : Rich Bottom Land, Season fairly Di;v (1897) Plat I : ooO lb. dissolved rock per acre ; yield, 13,597 (]t. Plat II : 700 11>. dissolved rock per acre ; yield, 20,0(30 (]t. (An expense of $7.00 made a gain of $358.55 over Plat J.) Value of land. Some land may be dear as a gift. Agricul- tural nitrogen is worth $0.15 a pound, potassium $0.06, ground limestone $0,005, and phosphorus $0.03. At these prices let us compare the values of twT) samples of land. Pounds in 2,000,000 Pounds of Soil Plant Food ALVNITOBA Vali'e Bavarian Barrens Value Phosphorus . . . Potassium .... Nitrogen .... Calcium .... 2,530 17.100 20,100 27,000 $75.90 1,020.00 3,015.00 135.00 Trace None Trace 1380 $0.00 0.00 0.00 6.90 Total values ...... $4,241.90 $6.90 Of course, beyond a certain limit additional amounts of any plant food may not be of immediate value, but the above fig- ures indicate a fundamental reason for the rush of agricultural emigration to the northwest. Still, with all the experience of BIOLOGY OF AGRI€tTL'rUK-Aa:;:BR9]5^l]CXlOX 101 the past with exhausted and abandoned soils, the people on these rich lands are again talking of the " inexhaustible fer- tility" of the soil, and burning their straw and manure or hauling the latter onto the ice to befoul their streams. A comparison of virgin soil in the Canadian Northwest with soil adjoining it which had been cultivated twenty-two years showed a loss of nitrogen per acre from 6936 to 4736 pounds, or 2200 pounds, a loss of |330.00 worth of nitrogen per acre. Fertility Contained in Different Farm Crops (Approximate maximum amounts removable per acre annually) Pounds Pkodick YlKLD NiTROtiKX Pho.sphohus POTASSrUM Yam i; Corn, grain . . . 100 bu. 100 17 19 116.65 Stalks, cobs . . . 3T. 50 H 54 10.93 Corn crop . . . 150 m 73 27.58 Wheat, grain . . .50 bn. 71 12 13 11.79 Straw 2iT. 25 4 45 6.-57 Wheat crop . . 96 16 58 18.36 Alfalfa hay . . . 8T. 4001 36 192 72.60 Cotton lint . . . 1,000 lb. 3 .4 4 .70 Cotton seed . . . 2,000 lb. 63 11 19 10.92 Cotton stalks . . 4,0001b. 102 18 59 19.38 Cotton crop . . 168 29.4 82 31.00 Potatoes .... .300 bu. 63 13 90 15.23 Apples 600 bu. 47 5 57 10.62 Leaves 4T. 59 7 47 11.88 Wood growth . . Jq of tree 6 2 5 1.26 Apple crop . . 112 14 109 23.76 Fat cattle .... 1,0001b. 25 7 1 4.02 Fat hogs .... 1,0001b. 18 3 1 2.85 Milk ...... 10,0001b. 57 7 12 9.48 Butter 4001b. 0.8 0.2 0.1 .14 1 Much of this nitrogen is taken from the air, and the roots go so deep that even the phosphorus and potas.sium may be largely supplied from layers of soil below the reach of other crops. 102 ■: ': ^ r* "'? r' V CIVIC .BIOLOGY Losses in plant food due to cropping. Too many have not counted the cost of a crop to Mother Earth, and hence have taken it as a free gift, with no thought of making any return. The table above, modified from Hopkins,^ shows wliat a few typical crops actually take from the soil. Complexity of the problem. It remains to add that the prob- lem of soil fertility is much more complicated than the above brief statement would seem to indicate. Warren says : " The fertile surface soil may be carried away by erosion, by wind, or water. Probably more soil fertility is lost in this way than by cropping." ^ So the humus may be exhausted, and with it the soil may lose its power to hold moisture, so that it becomes hard and dry, and plant food in any amounts is of no avail. Or soil may be too wet and require drainage, and too free drain- age may rapidly leach away nitrates, potash, and lime. Chem- ical changes are going on within the soil, and additions are being made to it from the air, which lead some authorities to claim that mineral plant foods are practically inexhaustible. Poisonous substances, it is claimed, are excreted by the roots of certain plants, so that proper rotation of crops is all that is needed to maintain fertility indefinitely. That is, the soil is " A bank account which requires for its maintenance only the rotation of the check book among the members of the family!" Hopkins sums up the whole matter as follows : The possible enormous and irreparable damage of such teaching lies in the fact that even our remaining supply of good land will ultimately be depleted . . . beyond the point of self-redemption, thus repeating the history of our abandoned Eastern lands, where the rotation of crops was the common rule of practice for more than a hundred years. Problems in animal industry. Perhaps the most important dairy records are those of Professor Fraser of the University of Illinois. He tested 554 cows in 36 commercial dairy herds, each 1 Soil Fertility and Permanent Agriculture, p. 154. 2 Farm Management, p. 184. BIOLOGY OF AGRICULTURAL PRODUCTION 103 for a full year. The best 25 per cent produced 301 pounds of butter fat per year ; the lowest 25 per cent only 133.5 pounds. He concludes from the experiment as follows : " If it costs $30 a year to feed the poorer cows and $38 a year to feed the better ones, then at present prices a herd of 25 of the better will produce as much net profit as would 1000 of the poorer cows." The Hoi stein, Banostine Belle de Kol, held the world's record for butter fat in 1912 — 1058 pounds in one year. By courtesy of the Ohio Farmer Fig. 4U. Banostine Belle de Kol According to above figures, five such cows would yield the net product of 25 of the better dairy cows, and their calves might be worth even more for breeding purposes. The highest dairy record for 1913 is 1073 pounds of butter fat, scored by May Rilma, a Guernsey. And so progress in every branch of agriculture becomes a game which, if well played, may ever " lighten and sweeten toil." Poultry offers perhaps the most practicable field for ele- mentary experiments in the breeding and care of animals, and 104 CIVIC BIOLOGY any branch of the industry, from pigeons and chickens to geese and turkeys and native game birds, is Ukely to yield a sub- stantial profit from the start. One of the chief problems of present interest is that of breeding for egg production, the accepted unit being the number of eggs laid in a year. Some recent American records are shown in the table below. Variations in growth of flesh or fat are similar to those in milk and egg production. This means that one animal may not digest or assimilate food as well as another, or one may use its energy in developing nervous activity (which is not edible) while the other is grow- ing flesh and fat. Experiments have shown that one animal may thus require over 30 per cent more food to gain a pound of flesh than another. Here selection and thorough breeding are saving enormous losses and increasing productive efliciency. Amkricax Egg Records Fig. 50. Hen C. 521 Bred by Professor James Dryden, Corvallis, Oregon Year Number of Eggs Description of Hex IftlO 282 Barred Plymouth Rock, Agricultural College, Guelph, Ontario 1911 281 White Plymouth Rock, Lady Showy on, Illinois 1912-101.3 30.3 Hen C. 521, cross between white Leg- horn and barred Plymouth Rock. Reared at the Oregon Agricultural College, Corvallis, Oregon ^ 1 This is held to be the world record up to date. In attempting to make a record of this kind it is necessary to have official control to guard against any possible mistakes or falsification, if the records are to stand. BIOLOGY OF AGRICULTUKAL PRODUCTION 105 Special problems. Keep the record of a cow and figure profit or loss on basis of cost of feed and care. Trai>nest a fiock of hens and study variation in egg production, making results the basis for future breeding and improvement of flock. Try different chemicals or fertilizers in strips across the rows in the garden, to discover special needs of soil or crop. Fig. 51. Growth and oppor- tunity Oue of the 8 carrots, thinned to 4 to the foot, which weighed 11 pounds, and the smallest of 50 carrots, unthinned and standing 25 to the foot, which weighed 1.7 jiounds Fig. 52. Parsnips show- ing result of a hard spot in the row Experiment with different consistency of soil : trench a strip two or three feet deep, dynamite a strip, or even leave a hard strip across the garden, in order to study differences in production due to tillage (Fig. 52), and thin plants to different distances (Fig. 51). Test seeds of all kinds before planting in garden or field. By blow- ing off the light, small seeds and planting the 5 or 10 per cent of the heaviest and strongest seeds, crops of remarkable vigor and evenness are 106 CIVIC BIOLOGY secured. Saving seed from strong, productive plants — potato, wheat, corn, cotton, timothy — has given rise to a large increase of production without other change or difference in method of cultivation. In order to unite the work of the school with the interests of the community, offer to test all kinds of seeds, especially corn, if in a corn- raising section. An increase of from 30 to 40 per cent in the corn crop of the district has resulted from such testing. A most remarkable fact has developed with reference to seed potatoes. Immature tubers, about half or two thirds grown or ripened, may pro- duce twice as many potatoes as dead or so-called overripe seed from the same field. Immature seed potatoes are specially raised and saved in Europe, and this one factor may account for the great difference in favor of European over American yields — more than 2000 bushels per acre as compared with less than 1000 as the best American record. This must be a matter of activity, or vigor, of buds, or of availability of the starch food supply. For information on raising seed potatoes, write your state experiment station. Work for record production of thoroughly cultivated, pure-bred, pedi- gyefe single plants — the world-record hill of potatoes, the best plant of corn, wheat, cotton, oats, sunflower, tomato, cabbage, currant, raspberry, blackberry, grape, peach, plum, cherry, apple, etc. More may be learned from intensive practical study of a few plants, each of which is a special experiment, than from any number of less intelligently cultivated acres. In all such problems, with both animals and plants, we neied to learn all we can about the laws and forces of heredity, breeding, and breeds, and also all we can about favorable en- vironment, feeding, care, and treatment. The former topics are treated further in the appropriate chapters. The latter should be made subjects of special study whenever it is possible to have the care of either an animal or a plant, and to secure an authentic record. Any one, by applying " cultivated thought," may render a world service by winning a new world record. CHAPTER X INSECT TYPE PROBLEMS: IMPORTANT FLIES If each egg of the common house fly should develop, and each of the larvae should find the food and temperature it needed, w^ith no loss and no destruction, the people of the city in which it happened would suffocate under the plague of flies. — Jordan and Kellogg, " Evolution and Animal Life," p. 59 And as for the typhoid fly, that a creature born in indescribable filth and absolutely swarming with disease germs should be practically invited to multiply unchecked, even in great centers of population, is surely nothing less than criminal. — L. O. Howard What flies do. During the Spanish- American war typhoid fever wounded 20,738 United States soldiers and killed 1580. The chief means of spreading this infection were the swarms of flies which infested the army encampments. To emphasize this menace to health, Dr. Howard has suggested that we change the name of the house fly to tyjyhoid fly. This opened the way for thorough investigation of the insect, and its filthy habits were soon found to render it the possible distributor for many other filth-disease infections. Tuberculosis, cholera, enteritis (including epidemic dysentery and cholera infantum — the fly-time "summer complaint" of infants), spinal menin- gitis, bubonic plague, smallpox, leprosy, syphilis, gonorrhea, ophthalmia, and the eggs of tapeworms, hookworm, and a num- ber of other parasitic worms - — for all these and many more the fly has been discovered to be a ready actual or potential carrier. Since the fly is proved to be such an active agent of transmis- sion between all manner of filth, on which it feeds and in which it breeds, and human foods, Dr. Stiles, of the Hookworm Commission, has proposed to call it the filth-disease fly. 107 Fig. 53, Flytraps for barnyard or stable window 1, first model as found after being set one week ; 2, same, emptied by lifting off top frame ; trap lifted from bottom board to indicate construction ; 3 and 4, larger window trap, showing construction and in position. The small traps in 3 are merely to take off samples of the catch for analysis. These traps are made to fit the window about which flies naturally congregate, gunny sacks are hung over the other windows to darken them and to flap in the wind, and, when properly placed and managed, one trap will catch practically all the house, stable, horn, lilack, bot, and blow flies and even the mosquitoes that try to get in ut, or that either feed or breed about the stable 108 IMPORTANT FLIES 109 First necessary step in health conservation. The most sig- nificant fact in the situation is that only by eliminating the fly can we form any notion of how much present sickness it is causuig. On this account health oiftcers everywhere are The figure may be supposed to represent a model I'J inches wide, 12 inches tall, and 10 inches thick — a convenient size for ordinary use in a city yard. The speciti- cations Avill then be : two end boards J inch or I inch thick, 12x 10 inches ; four strips for the top frame, Ix i inch, two 12 inches and two 9 inches long ; Avire for top frame, 10 x 12 inches (raw edges folded over ^ inch); two top shoulder strips Ix^ inch, 11 inches long ; four bottom strips I inch thick and 12 inches long, two § inch wide and two 1 inch wide ; screen Avire for sides and bottom in one piece, 12 inches wide and 41 inches long (allow 1 inch to fold over raAV ends, J inch each) Fig. 54. Cross section and detail of stable-window or barnyard flytrap These traps may be of any convenient size, to suit conditions, and may be made of box boards, strips, and screen wire. It is Avell to plan to use wire of standai-d widths. If used on the ground, the traps may be made without the trap-folds in the sides, Avhich do most of the catching when the trap is set in a stable Avindow. Fold the wive squarely at the angles indicated in the figure. A, D, C, J), K, F, G, and at these points snip in 5 inch. Fold the 5-inch flaps to a right angle, turning them in directions indicated by small hooks along the course of the wire (dotted line). This allows the bottom ridge and the trai>-folds to drop smoothly inside the end boards, and the flaps are tacked to the end boards to help hold the wire in place and make the trap absolutely fly tight so far as any cracks along the corners are concerned. The holes in the s\ure are punched by pushing ten 40-penny wire spikes through the exact apex of the bottom ridge, about 1 inch apart. If good bait is used, the flies may become much crowded here. (This must be a sharp 90° angle, not a rounded dome, or the flies will not find the holes.) Three holes are sufti- cient for the side folds. Punch all these holes after the wire is tacked in place. The trap is really as simple as a box. AVith proper tools a boy ought to cut out the end boards, rip out the strips, nail up, fold, and tack the wire, all in about one hour. The main feature of the trap is the 5-incli crack opening upward to the bait saying, in effect, '' Clear the air of this universal distributor of filth, in order that we may be able to trace other ways of dis- ease infection." Thus extermination of flies comes to be the necessary first step toward the effective prevention of disease. 110 CIVIC BIOLOGY The evidence we have indicates that ahnost all dysentery and summer complaint (millions of cases and 56,000 deaths annu- ally) are caused directly by the house fly. One third of the typhoid (about 300,000 cases and 30,000 deaths) is estimated to be caused by flies, and an unknown and unknowable pro- portion of tuberculosis, spinal meningitis, and other filth infec- tions. Thus it is quite possible that flies carry the infections which cause from 70,000 to 100,000 deaths annually. About 2 people in the United States die yearly from bites of poisonous snakes ; rabid dogs bite about 100 with fatal effect. Can you think of a more deadly animal than the common typhoid, or filth-disease, fly ? Spread of animal diseases. An additional factor is the prob- able causation of disease among domestic animals. As they are not even partially protected by screens, and flies swarm about their foods, epidemics of such diseases as fowl and hog cholera, bovine and fowl tuberculosis, and foot-and-mouth disease are almost certainly spread by flies. This matter has not been investigated as it should be, but we are likely to see a remarkable clearing up of animal diseases as soon as we exterminate flies from our farms. Futility of fly screens. Finally, a minor consideration is the (estimated) $12,500,000 we pay annually for screen windows and doors, which are not only expensive but disagreeable at best. These do not solve the problem, even if they did keep the pests out of our homes. We must prevent flies from contaminating foods on the farms and in the stores and mar- kets of our cities. Thus the fight against the common enemy must be community-wide, and, since one careless or ignorant household can breed flies enough to infest all the houses within a quarter of a mile, positively every one must cooperate. Need of universal cooperation. The general situation, espe- cially the relations between country and city, is shown so clearly in the following case that we quote in full from the IMPORTANT FLIES 111 Bulletin of the Indiana State Board of Healthy July, 1910, The note is entitled THIS HAPPENED IN INDIANA A few days ago a physician in Martin County called on the state bacteriological laboratory for Flexner's antinieningitis serum. Dr. Simonds went to the case and found a seven-months-old baby suffering from a very severe gastro-enteritis with the not infrequently accom- panying meningism. The father of the child was a farmer living in a four-room house with few or no modern conveniences. On the wall of the largest room was a family-history chart done in brilliant colors, with three columns of lines for the record of marriages, births and deaths. The parents had been married ten years and six children had been born to them. In the death column were the names of four chil- dren, all under two years of age. Another name has since been added to this list. The cause of this sad story became evident on inspection. There was a shallow surface well in the back yard, a short distance from an open privy. A large pile of manure lay uncovered, almost against the side of the barn. If this farmer had attempted so unthinkable a thing as transforming his premises into a fly hatchery for commercial pur- poses, he could not possibly have achieved a more brilliant success. The family and several of the neighbors were eating dinner on the back porch. Flies were swarming all over the table, but showed a special liking for a particular dish. They were so thick on this that it was absolutely impossible to tell definitely what it contained until one of the neighbors swung her arm over the table and cleared them away long enough for one, by looking quickly, to see that the dish contained cot- tage cheese. The flies were so thick in the house that it was only with difficulty that they were fought away from the field of the spinal puncture and kept from lighting on the instruments. On the death certificate the cause of the death of this child was doubtless given as "Gastro-enteritis." It would have been more in keep- ing with the facts to have said " Poisoned by Flies." Different kinds of flies. About 43,000 different kinds of flies and related gnats and mosquitoes have been described, and Dr. Howard estimates that this group of insects contains no less than 350,000 species for the whole world. One large 112 CIVIC BIOLOGY family, the tacliina flies, many of which look much like com- mon house flies, feed upon other insects and are among our most effective helpers m holding certain insects in check. Tachina flies are being imported from Europe to destroy gypsy and brown-tailed moths. Syrphus flies are another large family which feed upon other insects. Tachma and syrphus flies are found about rank vegetation in which other msects abound. Of flies caught in and about houses the typhoid fly gener- ally numbers over 90 per cent. It is distinguished by the " elbow " on the fourth vein as it curves up to the third vein near the tip of the wing (Fig. bb}. The proboscis is an extensible trunk adapted for lapping up liquids, and cannot be used for either biting or piercmg. The foot is provided with claws for climbing- over rough surfaces, and also with two pads (pulvilli) covered with sticky, tubular hairs, which enable the fly to walk on ceilings and windowpanes. No more effective mechanisms for collecting dust could be designed than a fly's feet and proboscis, a combination of six feather dusters and thirteen damp sponges. The constant " cleaning " movements of flies are clearly designed to rub off and scatter the adhering germs everywhere they go. The '' little house fly " (Fan7iia eanicularis)^ smaller than the common fly, is often seen in swarms hovermg under chandeliers. In breeding and feeding habits it resembles the house fly. Other flies found about houses are the following : Bluebottles, greenbottles, and flesh flies, or blowflies, which so frequently lay their eggs on meat. These flies are scav- engers, but we can dispose of dead animals hi much more Fig. 55. Wings of {a) house fly (6) stable fly, (c) little house fly {(1) horn fly Photograph hy I. A. Field IMPORT AX T FLIES 113 sanitary ways than by leaving them to the blo\\^ies. Related to these, and of importance in the southern states, is the screw- worm fly ( Chrysomyia macellaria)^ which oviposits on wounds, the maggots feeding upon living flesh. These are the flies that sometimes lay their eggs in nostrils or ears of children or of people if asleep out of doors in the daytime, tlie maggots causing painful and even fatal wounds. The stable fly (^Stomoxys calcitrans)^ which has somewhat the appearance of the house fly, except that it is provided with a strong, piercing beak, sucks the blood of animals. This fly is now convicted of moculating the germs of infantile paralysis with .its bite. It also causes great suffering to cattle. The smaller liorn fly (^Hcematohia serrata^, imported from Europe about 1886, is another bloodthirsty pest of cattle, biting both by night and day. It may be recognized by its habit of clustering in masses around the bases of the horns of cattle, and may be trapped by the method recommended for the stable fly. The black flies, deer flies, sand flies, and the many botflies of horses, cattle, and sheep are all of civic importance to the districts where they abound. The black flies of the genus Simtdmm are now under suspicion as possible carriers of pellagra. They breed in running water. Life history of the typhoid fly. In order to discover best ways of attack, we must study natural enemies from every point of view. The ease with which mosquitoes have been exterminated has suggested similar methods for dealing with flies. But mosquitoes breed only in stagnant water, which is easily drained, filled, stocked with fishes, or oiled. Flies breed in decaying filth, chiefly in horse manure, but can breed in any Fig. 56. Stable flies that a boy, with an insect net, caught on a cow in one day lU CIVIC BIOLOGY wet, fermenting matter, animal or vegetable. The maggots are hard to kill ; they will live for an hour or more in pure kero- sene oil and for over haK an hour in alcohol. Tobacco kills many insects, but house flies have been bred from the snuff on a druggist's counter. This means that as long as there are flies about, they will find something in which to breed, and that, with stables and barn- yards, gutters, roadsides, and acres of pastures, with accidental accumulations, lawn clippings, compost and rotting weeds and fer- menting garbage, preven- tion of breeding by doing away with breeding places and materials is beyond human possibility. It is easy in comparison to exter- minate the breeders them- selves. Still, proper disposal of all this waste matter comes to be a problem of greatly increased importance when we attempt to prevent flies from breeding in it. If material becomes infested with eggs or maggots, the best treatment of it is probably to turn it out in the hot sunshine and dry it as completely as possible. If this cannot be done, the maggots may be killed by saturating the material with a solution of iron sul- phate (copperas), two pounds to the gallon of water. Treatment of stables with chloride of lime has been recommended, but this is expen- sive and disagreeable, and the fumes (chlorin) are likely to injure the animals. Stiles has buried infested material six feet deep and found that the flies work their way out. For the farm home the cost of han- dling is doubled and fertilizer value reduced from 55 to 69 per cent by Fig. 57. Member of Juuiur !Saiiitary Police of Cleveland Photograph by Dr. Jean Dawson PLATE II. LIFE HISTUKY UF THE GYPSY INIUTH 1, egg cluster ; 2, single egg (enlarged about four diameters) ; 3, caterpillar; 4 and 5, female and male pupae ; 6 and 7, female and male moths ; 8. im- ported lion beetle devouring a caterpillar. (All except 2 about natural size.) IMPORTANT FLIES 115 antiquated methods of storing, piling, and rotting. All stable waste should be hauled and spread on the land daily. It will generally become too dry for flies to breed in. The most expensive and disastrous fallacy in this whole problem is the " fly-tight " pit or receptacle for stable waste. This has been and still is recommended under the plausible excuse, " Make them fly-tight, so the flies cannot get in to lay their eggs." Eggs by the million are laid in the material before it is put into the pit ; the tight construction makes it an artifi- cially perfected fly incubator, and when it is opened, as it must be daily, the flies swarm out. By this method we actu- ally go to great labor and ex- pense to breed more flies. In cities, instead of fly-tight stable pits, we should have, by city ordinance, readily ac- cessible elevated hoppers or concrete-floored bins, and the city should arrange to empty these clean to the concrete at least once a week from May to October. It would be much better, for purity of air and economy of fertilizer, to have this done daily. By proper or- ganization of routes the city should be able to gather and dis- pose of the material at greatly reduced expense over scattering and irregular private cleaning. It ought to be managed so as to pay stable keepers fertilizer value of material, less cost of handling, and still deliver it regularly to gardeners and farmers, as planned for, and for much less than it costs to collect the material privately. If this is not feasible, then the proper officers can license farmers and truck gardeners to collect from specified stables, under contract to remove the material in the cleanly manner specified and at weekly intervals. Besides stables, the city should maintain strict supervision over all Fig. 58. First model of outdoor fly ex- terminator This has been set fifty-eight minutes and has caught 2000 flies. It caught 2 quarts (about 16,000) the first day, aud might as easily have caught 20 quarts if they had been there to catch — a vacuum cleaner of the air for flies. Designed by the author 116 CIVIC BIOLOGY stockyards and slaughter-houses, public dumps, and all industries which handle materials likely to breed flies. It is utterly uncivilized and brutish that accumulations of filth, which allow flies to both feed and breed, should be permitted to vitiate the best efforts of thousands of good people, cover their foods and homes with filth, and cause not only annoyance but disease and even death.^ The eggs of flies hatch in about eight hours into maggots which feed actively and complete their growth hi six or seven days. They then burrow into the ground under a manure pile (hence the need of concrete floors) and transform into brown puparia, from which they emerge as adult flies in three days. After coming out as adults they fly about over an area not generally more than one thousand yards in diameter, and feed or drink from two hundred to tlu-ee hundred times a day for from ten to fourteen days before maturing their first batch of eggs. This actually delivers the enemy into our hands. It means that, with flytraps on every garbage can or swill barrel, and with everythmg most attractive to flies very carefully kept in these receptacles, not a single fly will succeed 1 In a large city the writer found, opening on an alley, and within a block of a great open public market, a pile of horse manure, entirely unprotected, at least thirty feet in diameter at the base and fourteen feet high. The outer layer of this whole pile was a solid, moving mass of housefly maggots. A moderate estimate for that pile would be ten barrels of fly maggots, which would make, when they reached their growth and emerged, from twenty to thirty barrels of flies. These flies were swarming black over the meat blocks and meats, fruits, fish, candies, cakes and pies of the whole market. The market people (some few had electric fans) were wearing themselves out shoo- ing those flies from one to the other and back again. The filth of that manure pile was being carried into thousands of homes with the market supplies. The flies were feeding in the market and in hundreds of kitchens in every direction and going back to the manure to lay their eggs. It is unfair to place on the market people the burden of trying to protect their foods from flies under such conditions. The horses in this large stable were kept on the second floor ; the manure could have been cleaned into a hopper opening downward into a dump cart in the alley, and every morning before daylight, by effective civic organiza- tion of the work, it might have been out in the country and at work in the land, a paying proposition instead of an insufferable nuisance. IMPOKTAKT FLIES 117 in feeding for two weeks without getting caught. In this case no more eggs will be laid, and the pests will vanish. Possible multiplication. Allowing ten days for eggs to become adults, and, for convenience, ten days of feeding between emergence and oviposition, figuring that a fly lays one hundred and fifty eggs at a batch and lives to lay six batches, compute the increase of a pair of flies beginning to lay May first. Half the progeny are supposed to be females. Test the following figures : May 10 . 152 flies 20 ;J02 flies aO 11,702 flies June 10 ;M,302 flies 20 911,952 flies 30 0,484,700 flies July 10 72,280,800 flies 20 325,683,300 flies .30 1 5,746,670,500 flies The common-sense question is, Why not let this pair of flies catch themselves in May ? This rapid increase also means that anything short of extermination is hardly worth the effort. A fly is possessed of no more cunning than shot rolling down a board, and the last pair will run into a trap as easily as the first. Why not let them all catch themselves ? Hibernation. Very few house flies survive the winter in Canada and the northern states, and these hibernate as young adults in cracks about buildings. They come out of winter quarters ravenously hungry and feed for about a week, at least, before beginning to lay. If at this critical time every household had some effective form of outdoor trap ready for them, every early spring breeder would be caught, and the 1 This last figure would equal about 143,675 bushels of flies from one pair in three months. If we continue the breeding through August and Septem- ber, the figure is 1,096,181,249,310,720,000,000,000,000 flies. 118 CIVIC BIOLOGY whole battle would be won for the season. The first commu- nity that does this with absolute thoroughness, and whose every member is intelligent enough to realize the 143,000 bushels that one pair might propagate in three months, will first be free from the world-wide, time-old plague of the " house fly, disease carrier," and from the diseases it carries. 1 2 A Fig. 59. Outdoor fly exterminator as adopted for manufacture 1, attached to garbage can (make hole in cover as large as inside of ring, to let in plenty of light) ; 2, on ring with which attachment is effected ; 3, on its own good-sized bait pan. Designed by the author Sketch a plan which shall prevent all flies — typhoid, stable, horn, and flesh flies — from either feeding or breeding about your own home. If the fight is carried out of doors into the camps of the enemy, this becomes one of the easiest problems to solve in the whole range of insect life, and its solution com- pletely relieves us of the need of screen windows and doors, as far as flies are concerned; and, expense aside, screenless windows and doors in summer are a luxury. IMPORTANT FLIES 119 Study and experiment with all the most likely devices on the market for outdoor fly extermination, and invent better ones yourself, if you can. With the traps already available, outdoor fly extermination, as one man who tried it has said, " is so easy as to be almost humorous and so effective (the flies disappear so suddenly) as to be little short of the uncanny." Fig. 60. " Getthelastone " fly nets The handles are long enough to reach the ceiling without stretching and the floor without stooping, enabling one to catch any stragglers that may get by the traps and into the house. Make them of finer-mesh mosquito net according to directions (Fig. 5), cutting six nets to the yard. Long-handled swatters were tried, but they too often spotted the ceilings and did not prove as effective or easy to use as the nets. A larger insect net is most effective in exterminating stable and horn flies from a dairy. Designed by the author Civic fly campaigns. As the fly problem becomes generally understood by a community, the campaign comes naturally to a dollar-and-cent basis. People will not trade in fly-infested stores, markets, or milk depots, or patronize hotels or res- taurants that are not free from flies. For this reason store and restaurant keepers must see to it that no fly feeding or breeding is possible on their own premises, and they must 120 CIVIC BIOLOGY insist that all their neighbors do likewise. Thus general civic cooperation tends to enforce itself along lines of financial necessity. Work out a plan of campaign good enough to in- sure enlisting every home. In order to give time for discus- sion and publication of plans for the active work the following spring, this should be done in connection with insect lessons in tlie early fall, when flies are abundant and troublesome. Killing the breeders in the fall is as good or better than kill- ing them in the early spring, and on one farm where this was done scarcely any flies appeared the next spring, wliile farms half a mile away were swarming with them. Nothing can take the place of bringing the actual speci- mens into the laboratory and of studying the flies and mag- gots as' they swarm in and about the filth of outhouses and stables, gutters and spittoons. If every one could be shown, — could be made to see and study the flies as they live, — the community would be in the fight to a man, and this is all we need for complete success. One teacher who tried this writes: Last week I had some maggots in horse manure.^ It was an unusual thing to do in school, but I wished to emphasize the idea of filth. I think it was successful, for the disgust was great when they saw that they changed into flies. People are so irresponsible that they have to be shocked to awaken their fighting power. Things to avoid in civic fly campaigns. During any season when breeding is possible, avoid offering prizes or money enough to encourage raising flies. Also, never give more than ten days — the time of a gen- eration— in prize contests during the breeding season. A fortune might be made raising flies at ten cents a quart. Avoid delay. While spring is the idea] time to start a campaign, one begun in midsummer or even fall will result in much good and will help educate a community in plans and methods for effective work the following season. 1 This can be done in a safe and cleanly manner by means of large bottles. They must be stoppered securely, as maggots are strong and can burrow and squeeze through minute cracks. IMPOKTANT FLIES 121 It has been customary in many early spring campaigns to offer children ten cents a hundred for all house flies brought in before, say, the first of May, or before breeding begins in the locality. On this basis bills of five or six hundred dollars may be expected in good-sized cities, and it would probably be better to offer one cent a hundred, and be sure to avoid paying for bluebottles, greenbottles, or other large flesh flies. These will always be killed along with the rest, but they begin active breeding much earlier in the spring and, if not ruled out, might easily swamp any treasury. The four flies whose wings are shown in Fig. 5.5 may be included in the list to be paid for. Life history of the stable fly. During the summer of 1912 a serious outbreak of stable flies occurred in grain-raising sections of northern Texas, Oklahoma, Kansas, and Nebraska. Cows fell off in milk and even went dry, operations had to be suspended in the fields because the animals could not endure the torment of the swarms of flies, and many mules, horses, and cattle were killed outright. Investigation showed that the flies were breeding in the following substances, named in approx- imate order of importance : in the wet, fermenting straw of oats, rice, barley, and wheat, and in horse and cow manure, especially where mixed with straw. Thus most of the trouble arose from decaying strawstacks in the fi«^lds and from uncleaned barnyards. The minimal time recpiired for the different stages of development was found to be : i^gg, one day ; larva, eleven days ; pui>a, six days ; making eighteen days from egg to adult fly. Probably most of the stable flies pass the winter in the larval or the pupal stage and so are ready to emerge during warm spells in winter and with the first warm days of spring. Where stock can be stabled, these flies can be successfully caught in the stable window traps shown in Fig. 58. Life history of the horn fly. The horn fly breeds exclusively in freshly dropped cow manure. The flies leave the cows and swarm to fresh drop- pings to lay their eggs, often covering the material as thickly as they can stand. This occurs especially in the early morning hours, and by following the herd a few mornings with a hand sprayer loaded with kerosene or any good oil mixture used to keep the flies off from ani- mals practically all the horn flies can be killed. Covering the fresh droppings with lime also prevents the flies from breeding in them. Health statistics. Watch local health statistics and re- ports, especially as to typhoid and cases and deaths from summer complaint, tuberculosis, and pneumonia, and any 122 CIVIC BIOLOGY other prevalent filth infections. If the stable fly has been successfully dealt with, compare the monthly reports on cases of infantile paralysis with corresponding reports of previ- ous years. 1 Some people may object to fly campaigns on the ground that flies were created for a good purpose. Any such should refer to Exodus viii, 31 : And he [Moses] removed the swarms of flies from Pharaoh, from his servants, and from his people; there remained not one. All we ask is that " there remain not one." 1 While the above is passing through the proof the discovery is announced that maggots of flies (species not determined) which develop in the bodies of chickens dying of limber neck infect animals to which they are fed with the germs of infantile paralysis, or poliomyelitis. All such fowls should be com- pletely burned up. If buried, the flies easily work their way to the surface and may spread the infection. (Latest evidence points to contact infection by human carriers, and excludes any influence of flies or other insects in spreading this disease.) CHAPTER XI INSECT TYPE PROBLEMS: MOSQUITOES Mosquitoes and disease. The discovery that malaria and yellow fever are transmitted by certain mosquitoes shows how /^ \ Al ^v ,Ki\ A/ ^ ^ ^ V 3 ^4^ ^ 1 Ay m H 1 ^^L ^ \ i? Im Fig. 61. Anopheles mosquitoes and malaria in a city A, Anopheles mosquitoes breeding; dots, houses where malaria occurs. There would be more dots in various parts if there were any houses important a r61e an insect may play in the affairs of human life. No obstacles have so seriously blocked the progress of civilization in the tropics as these two diseases. The Panama 123 Adults esmk^ Ficx. 62. Left, Anopheles (malaria) ; center, Culex pipienft (common nuisance) right, Aeclefi calopiis (yellow fever) 124 MOSQUITOES 12^ Canal has been made possible mainly through the control of malarial and yellow-fever mosquitoes. Of the ten genera of mosquitoes of North America, Anopheles, Aedes (a e^ dez), and Cidex concern us chiefly. There are three species of Anoph- eles distributed throughout the country, and it is important to remember that it is tlu-ough these mosquitoes only that malarial fe- ver is spread. This disease is not as fatal as some others, biit is important be- cause so widely distributed and because in ma- larial countries from 25 to 60 per cent of the people are af- flicted. In the United States, according to the estimate of Dr. 1^. O. Howard, there occur 3,000,000 cases, causing a loss of 1100,000,000, annually. In India, where the fever assumes a fatal form, 5,000,000 people have succumbed to it in one year. Anopheles is particularly active during the early part of the night. It may be distinguished from other mosquitoes at a EiG. 63. Aedes calopus — Yellow-fever mosciuito Egg, larva, pupa, and adult 126 CIVIC BIOLOGY glance by its mottled wings and by its posture. It resembles somewhat a thorn in the wall, standing as it does at an angle of almost ninety degrees to the surface, with proboscis in line with the body, whether the surface is vertical or horizontaL Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. 1 1897 1900 1895- 551 \ 1896 Av.462 1900- 1898- 1897- 1896- -1278 \ 1897- ■ 828 \ / \ 1898- -138 / \ / \ 1899- - 102 / \ \ / \ 1900- -40G / I \ 1901- ■ 17 - - 5- / \ / / ' \ / \ / / / // y' y' v. M \-- \ / y , / \ \ / y V / / / \ N \ \ ^^_"d 1896 ^..-- , ,^ S ,„ , ^ il. 1898- 1898- 1900-1901- Fig. 64. Yellow fever in Havana Aedes calopus. This is the mosquito responsible for the transmission of yellow fever, which in the memory of man has left its dead unburied in some parts of our country. Indeed, in the early part of the summer of 1905 a mosquito infected with MOSQUITOES 127 yellow-fever blood came on a cargo from Central America to New Orleans. The fever spread rapidly and by the middle of September 2462 people had been attacked by the disease and 329 had died. Aedes is the common rain-barrel mosquito of the South ; it is frequently referred to as the " calico mos- quito " because of conspicuous bandmg of its legs, thorax, and abdomen with black and white. This mosquito is unable to survive the winter of the Northern states (Fig. 63). Fig. 65. Outdoor laboratory work in a malarial district of the city Culex mosquitoes. To this genus belong our most common household forms. They are generally brown and may be dis- tinguished from Anopheles by the fact that they rest with body parallel to the plane of support and head and proboscis bent, giving a humpbacked appearance. While these mosquitoes are not known to be injurious to health, the annoyance and distress they cause furnish ample reason for the general move- ment to exterminate them. Culex pipiens is the common household pest throughout the country. Howard says these mosquitoes will not fly far from their breeding places unless 128 CIVIC BIOLOGY they are carried bj light and continued winds. With the exception of two species of Culex that breed in salt marshes and migrate for long distances, mosquitoes seldom go more 'than two hundred yards from where they are hatclied. In a town or city away from these marshes the work of extermi- nating mosquitoes is simple and not expensive. Indeed, the class in civic biology can accomplish the task as an interesting and valuable turn at outdoor laboratory work. Before begin- ning the work, however, much more should be learned about the habits and life history of the mosquito. Habits and life history. Mosquitoes are nocturnal ; during the bright part of the day they hide under leaves, in grass, in cellars, wells, cisterns, in barns, and in the dark corners of the house. Even the " day mosquito," Aedes^ does not fly about or bite in the bright sunlight of midday. As winter approaches, the female mosquitoes seek dark, damp places in cellars, caves, hollow trees, and loose bark in which to hibernate. Can you find them ? Mosquitoes may be distinguished from gnats and other mosquito-like insects by the presence of a fringe of scale-like hairs on the margins of the wings." Like many other insects, especially those that suck blood, they are strongly attracted or repelled by dift'erent people. It is a matter of common experience that some people are ainioyed by this class of insects much more than others. Odors like a mixture of oil of tar, oil of pennyroyal, and olive oil are effec- tual repellents, as is also a mixture of cedar oil (one ounce), oil of citronella (two ounces), spirits of camphor (two ounces), If an odor could be discovered that is highly attractive to mosquitoes, it might be effective in ridding a neighborhood of the pests if used in connection with a trap or some form of sticky fly paper. Mosquitoes seem to possess other likes and dislikes. They are attracted to dark colors and are repelled by lighter shades ; MOSQUITOES 129 and certain musical sounds seem to possess a charm. The song of the mosquito varies with the species and with the sex ; it is believed these insects find their mates by the pitch of their song. Mosquitoes are not without their natural enemies. Birds (especially nighthawks, swallows, and whippoorwills flying at dusk), also bats and dragon flies, feed upon adult mosquitoes. One observer reports having found six hundred mosquitoes :.i^|^illl ^ij^* mw^^ ^i^Xy^^..^' >2? I» Fig. 66. Collecting mosquitoes Equipment : insect nets and smaller scrim nets for use in w ater in the crop of a nighthawk. A minute red mite may often be found clinging to mosquitoes, and it is said to greatly reduce their numbers in some localities. Young mosquitoes are aquatic. Mosquitoes lay their eggs on the surface of water, usually about three days after they have taken a meal of blood. The eggs are laid in the early morning hours and hatch into larvse about two o'clock the same day. Oidex lays from two hundred to four hundred cigar-shaped eggs which float on end in boat-shaped masses. The larvse, better known as wrigglers, swim actively about in the water, 130 CIVIC BIOLOGY feeding upon minute forms of animal and vegetable life which are swept into their gullets by the constant motion of little brush-like mouth-parts. A long respiratory tube comes from the eighth segment of the body, through which the larva breathes by opening it to the air. After undergoing three different molts the larva reaches maturity and changes into a pupa in from ten to fourteen days. The pupa differs radically ^ ~r #■ -^ - JLai He; m ^ , 0 --... ^..^,.4 i«|: , :. I h s ^ ' . - - 1 >l ■ - J lm;%-\,^^ ^ I ■' ■"% mm " ':> 1 Fig. 67. Survey of mosquito breeding places by a normal-school class Equipment : bottles, timiblers, and saucers from the larva in appearance, and breathes from the ear-like organs on the thorax (Fig. 62). Except when disturbed the pupa remains at the surface of the water. After two days it splits down the back and the adult mosquito rises from the pupa skin. Anopheles and Aedes lay their eggs scattered singly, those of Anopheles floating while the eggs of Aedes sink to the bottom (Fig. 62). The larva of Aedes resembles that of Culex^ while that of Anopheles lies horizontally, just under the surface. MOSQUITOES 131 Its respiratory tube is short, its body black and spotted with tufts of long bristles protruding from the sides (Fig. 62). The pupae of the different species are not readily distinguished. Under favorable conditions the time required for the eggs to hatch and grow to adult mosquitoes is ten days ; when the weather is cold it may be indefinitely extended. Three days after emergence the adult may lay eggs. Culex has pro- duced from seven to ten generations in a season and Anopheles four. Allowing 150 eggs to a generation, the possible progeny of a pair of Anopheles in one season would be 31,000,000. The natu- ral enemies of immature mosquitoes are fishes, newts, salamanders, dragon-fly nymphs, the larvae of water beetles, and even young turtles. Location of breeding places. After members of the class have learned to distinguish the different mosquitoes and their larvae at a glance, they should divide themselves into groups corre- sponding to convenient divisions of the district to be studied. Each group should be responsible for a full report upon the breeding places and the kind of mosqui- toes found in its territory. Collect speci- mens and put the eggs, larvae, and pupae from each territory into separate glasses or into vivaria with screen tops (Fig. 69). Keep a dish of water and a bit of fruit (apple, grape, banana) in the vivaria for the adults and have green algae in the water with the larvae. Catch full-fed mosquitoes about animals or in bed- rooms and keep in glasses arranged as shown in Fig. 70. Fig. Insect-catching bottle For handling delicate in- sects this is better than a net. The essential feature is a paper cone opening in- ward through the thin cork 132 CIVIC BIOLOGY Watch for eggs, and examine the water for larvie. How many eggs were laid and how long did they take to hatch ? Wherever you have found mosquitoes breeding, indicate it upon a map of the locality with letters, A denoting the presence of Anopheles; C, Oulex; and Y, Aedes. Fig. 61 shows the relation between malaria and the Anopheles mos- quitoes as worked out in this way by a biology class. Fig. 69. Vivarium set up for studying mosquitoes Cheesecloth top with sleeved opening and glass dish of water in moss at one end Did you find that, in general. Anopheles breed by preference in spongy bogs and stagnant water, green with algge ; Aedes in cisterns, tanks, buckets, tubs, rain barrels, flowerpots, saucers, flower vases, and water pitchers; Oulex pipiens in ditches, stagnant pools, catch basins, or in any water near homes, indoors or out? But algae may quickly change any neg- lected water into a green bog hole for Anopheles to breed in. MOSQUITOES 133 Methods of extermination. It is fortunate for us in our work of exterminating mosquitoes that they pass the first three stages of hfe in water, and that the adults must come to water to lay their eggs, that is, mosquitoes are strictly dependent upon suitable breeding waters. In all successful campaigns undesirable pools in which mosquitoes may breed have been dramed or filled. Streams and ponds have had their shores cleaned of weeds, brush, and stumps, and have been graded so that pools were not left in which mosquitoes could breed after freshets and storms. Then they have been stocked with fishes which feed upon the young of mosquitoes. All water which was too temporary to drain or too polluted for fishes has been cov- ered with crude petroleum (one ounce to fifteen square feet of surface). This treatment has been repeated as often as wrigglers have appeared. A mosquito can walk on the surface of water but it cannot stand on oil ; hence, as all mos- quitoes come to the near-by water to lay their eggs, they soon perish. Precautions have been taken not to allow water to stand in tubs, barrels, or cisterns with- out being covered insect-tight. Through systematic application of these methods, Panama, Cuba, New Orleans, and many cities in the north have effectually rid themselves of mosquitoes. The results of these campaigns prove that the extermination of the mosquito from any locality is no longer a matter of doubt or experiment. Through drainage of salt marshes whole Fig. 70. Jam bottle and tumbler arranged so as to secure eggs of a single mosquito Fig. 71. Connecticut salt marsh before draining Fig. 72. Connecticut salt marsh after draining Photographs by W. E. Britton 134 INSECT TYPE PROBLEMS 135 states are being freed from migrating mosquitoes (Figs. 71, 72). Incidentally, the yield of marsh hay is increased on these swamps, so that it more than pays for the cost of drainage. Locating Anopheles and Aedes mosquitoes in a neighbor- hood does not necessarily mean that malaria and yellow fever are present. These mosquitoes are not dangerous to health unless they have first bitten people sick with malaria or yellow fever. Planning a campaign. You may carry on a campaign against the mosquito in a single neighborhood or you may conduct it as a city-wide movement. In either case offer your services as a class to the board of health. If malaria is present, your map showing location of breeding places of Anopheles might be offered to the board and cooperation secured in wiping out the disease. Arrangements should be made to have a doctor examine, free of charge, any one who has even a slight suspicion that he has malaria. Quinine is a cure for this disease, and every malarial patient should make use of this remedy (under the duection of a physician) and should be screened from mosquitoes to prevent them from becoming infected. Allow the newspapers to publish the results of your work, together with the accounts of mosquitoes and the methods of exterminating them. It is of the utmost importance that every one enter the campaign with enthusiasm, as a few care- less and ignorant, people may contmue to breed mosquitoes by thousands in all sorts of rubbish that can hold a small amount of water. CHAPTER XII mSECT TYPE PROBLEMS: CABBAGE BUTTERFLY (PONTIA RAPjE) Pontia rap(£. This white butterfly commonly seen flitting over garden and roadside, has long been a serious pest. It gains its familiar name — cabbage butterfly — from ravages of the larva upon the Crucifer family, especially the cabbage. In the northernmost portion of North America it is two-brooded, in the latitude of New England three-brooded, and farther south many-brooded. A butterfly has been known to contain over 500 eggs, and the progeny of a pair of cabbage butterflies in a season in the latitude of Boston is estimated as 31,375,500. The cabbage butterfly was accidentally introduced into America from Europe in 1860, and twenty -five years later it had spread over nearly the length and breadth of the land. This rapid invasion was due to the fact that its natural enemy, the ichneumon fly (^Apanteles glomeratus)^ was not present to hold it in check. This insect, however, was introduced in 1883 and is increasing rapidly. The cabbage butterfly may be collected in its different stages and the specimens kept in breeding cages (Fig. 73) for study. Larvae, thrive well in the laboratory if they are supplied with fresh cabbage leaves. Eggs and larvae. The small yellow eggs are deposited singly on the undersurface of cabbage leaves. Keep in water in the laboratory leaves upon which eggs have been deposited, noting how long it takes the eggs to hatch. Measure the young larva and note the time it requires to double in length. Does its color match that of the leaf upon which it is feeding ? What is the advantage of this ? 136 CABBAGE BUTTEKFLY 137 Place some larvte in a cyanide bottle. Study and draw a specimen. Can you find the six single eyes (ocelli) on the side of the head ? Note the small feelers (antennce)^ and the strong teeth (mandibles). How many pairs of jointed legs lias the thorax ? How many unsegmented legs (prolegs) on the abdomen ? Note the number of segments on the abdomen, and locate, if possible, all the spiracles. Pupa. After a larva is full-grown it ceases to eat and becomes restless, leav- ing the cabbage and crawl- ing about. When these symptoms are seen, keep a larva under a glass for observation. Note that it spins a mat of silk into which the claws of the last pair of prolegs are fastened, and a girdle of silk over the middle of its back. After it is thus securely fastened it draws •its head down. When it has remained in this posi- tion for some time, the skin splits over the head Female. Male. Fig. 73. Insect case to show biology of cab- bage butterfly and thorax, and we find a chrysalis ui place of the green larva. Draw the pupa as it is fastened by its girdle. Search for pup8D and make a list of places where they are found. Save as many as possible in order to see the butterflies emerge. Adult or imago. The rapid distribution of cabbage butterflies is due to their flight across the countiy from garden to garden, and to the conveyance of the chrysalis on carriages and trains. Follow the butterfly for fifteen minutes and keep a record of 138 CIVIC BIOLOGY all that it does. It sips nectar from flowers, and does much to fertilize them. The female imago is distinguished by having two black spots upon its fore wing while the male has only one. From your specimens in the laboratory study the butterfly, notmg its parts. Draw from the side and from above. Make drawings of the head from the 1^ — side, one with the proboscis I curled up, and another with it ra extended. (Place a little thin sirup near the head and watch the butterfly unroll its proboscis and sip it.) Compare the struc- ture of the body with that of the pupa. Mount, according to directions, the complete life his- tory of the butterfly (Fig. 73). Control of the pest. Artificial means of control are (1) Paris green, sprinkled over the leaves, killing the worms but not injur- ing the plant; (2) kerosene emulsion as a spray ; (3) water, heated to 130° F., may be used without injury to the plant; (4) systematic " netting " of adults* The most effective meas- ure, however, has been the in- troduction of its natural enemy, Apanteles glomeratus. This minute wasp-like insect deposits its eggs in the body of the cabbage caterpillar where they soon hatch and feed upon the tissues of the host. They grow until they are about to pupate, and then eat their way out and spin their silken cocoons on or near the bod}^ of their enfeebled host. The Fig. 74. Convenient arrangement for studying larvae . Two tumblers with card between CABBAGE BUTTERFLY 139 cabbage larva that is parasitized by the ichneumon fly usually dies before it transforms into a chrysalis. The adult ichneumon fly emerges from its cocoon in a week or ten days. It is not Fig. 75. Imported parasite of the cabbage butterfly — Apanteles glomeratus Open cocoon, adult insect, and mass of cocoons near parasitized larva. Highly magnified known how long it lives or how many generations occur in a year. The fact that it is holding the butterfly in check in some localities would lead to the belief that it multiplies more rapidly than its host. 140 CIVIC BIOLOGY The larva3 that are "infested with the parasites are usually a paler green and are not so easily bent. Examine a number of larvae, keeping in a closed vivarium those suspected of be- ing parasitized. How many parasites are found in a single larva ? The parasitic larvse begm to spin their cocoons as soon as they emerge from their host. With the aid of a lens watch this interesting process and note the length of time it takes to complete the cocoons. Apanteles does not escape without its enemies. Two small chalcis flies prey upon it, but thus far have not been effective in checking its ravages upon the cabbage worm. CHAPTER XIII INSECT TYPE PROBLEMS: ANTS No other group of animals presents such a maze of fascinating problems to the biologist, psychologist, and sociologist. — Wheeler, "Ants," p. 11 If I had to choose the form in which I would prefer to live again, I am not sure that I should not like to be an ant. You see that little insect lives under the conditions of perfect political organization. Every ant is obliged to work, to lead a useful life ; every one is industrious. There is perfect subordination to the good of all, discipline and order. They are happy, for they work. — Bismarck Economic importance. Over a thousand species of ants have been described, of which about two hundred belong to North America. As a group they are generally considered distinctly beneficial insects, though among so many species it is not strange that a few are injurious. Forel counted 28 dead in- sects per minute brought in by the foragers of a large colony, and estimated that this colony collected 100,000 insects per day. In China live ants are an article of commerce and are regularly used to control injurious insects in gardens and orchards. The Department of Agriculture has recently tried the experiment of importing a Guatemalan ant, the kelep, in the hope of discovering an effective enemy of the cotton-boll weevil. Observations of ants attacking injurious insects should be carefully recorded and reported to the class. Many species burrow deep into the earth, opening up the soil to air and moisture and preparing it for easy penetration of roots, and bring quantities of fine subsoil to the surface. In this way ants supplement the work of earthworms in the forrpation of vegetable mold. 141 142 . CIVIC BIOLOGY Three species, the red ant, little black ant, and pavement ant, are common household pests which can easily be looked up in state or national bulletins if they are locally important. ^ Serious damage is sometimes inflicted by the corn-root louse (^Aphis maidi-radicis). The eggs of this aphid are cared for over winter by the common brown ant QLasius hrunneus). They hatch early in the spring and the ants carry the young aphids to various grasses and weeds in the field, and later transfer them to the roots of the corn. Concerted work of farmers over an infested area by early spring plowing and repeated disk har- rowing, so that no weeds are allowed to grow before the corn is planted, effectually controls both ants and aphids. This topic is well adapted to laboratory demonstration and experi- ment in infested districts and where education is needed to secure general cooperation. The chief mterest, however, attachmg to a study of ants is their seeming intelligence and wonderfully perfect civic organization of the colony. The colony. Ant colonies are composed of queens, males, and workers. Queen ants are usually larger, are wingless when mature, and sometimes live fifteen years ; the males are smaller, always winged, and never live more than one year. The workers may be distinguished readily from the queens and males by their small size and lack of wings. They do all the work of caring for the queen and her young, gathering food, building and de- fending the nest, caring for plant lice (aphids)^ and waging war. Before mating, the queens have wings. In the summer and early fall clouds of young queens and males leave the differ- ent colonies, flying in thousands. The flight over, the queen is either adopted by an old colony or establishes a new one. When once established, she removes her wings and never leaves the colony. While there is usually but one queen in a colony, there may be as many as thirty. 1 Hodge, Nature Study and Life, p. 86 ff. PLATE 111. LIFE HISTOKY OF THE BKOWX-TAIL MOTU 1, egg cluster ; 2, single egg (enlarged five diameters) ; 3, winter nests (reduced about one half) ; 4, caterpillar ; 6, pupse, male at right, ventral view ; female at left, dorsal view ; 6 and 7, female and male moths ANTS 143 Food. Ants feed upon both animal and vegetable matter. Their foraging raids extend over a radius of forty yards from the nest. They often take food iirto the nest, and in cold climates they hibernate during the winter. Much of the food of the queen and larvae is eaten by the workers and regurgi- tated from the crop when they return to the nest. Ants have a preference for sweet food, such as juices of fruits, sugar, honey, and honeydew. Aphids secrete honeydew, and on that account are cared for by the ants, taken into the ant nests over winter, and in the spring carried back to the plants upon which they feed. But the aphids are among the insects most injurious to vegetation, and their protection by ants may be of great economic importance to us. Watch the problem in your own locality. Special senses. The organs of sight and hearing are very slightly developed in the ant, but the sense of smell is espe- cially keen. This sense is situated in the antennae. The ant travels from its nest and finds the way back by the odor of its own tracks. If a portion of the path the length of its own body is disturbed, the ant is lost and wanders about until it picks up the trail again, but a path left dry and undisturbed can be followed by it five days later. Experiments show that its own nest is evidently detected at quite a distance by odor, but the odor of other ants is supposed to be recognized only by touching with the antennae. Each species of ant has a distinct, characteristic odor. Different colonies also of the same species differ slightly. In general, the odor of one species of ants is offensive to those of another species, and causes aversion and hostility. This is shown by well-defined warfare and slavery. Slavery. While most ants will capture and carry away the young of another species whenever the opportunity is offered, there are three species in America (^Formica sangui- nea, Polyergus rvfescens, and Tomognathus americanus) that plunder the nest of their enemy and rear the young as slaves. 144 CIVIC BIOLOGY The slaves undertake the work of the new nest much as they woukl that of their own. Can you find ant colonies with slaves ? Warfare. Many comparisons have been made between ants and man because of the diversity of their activities. Ants are said to indulge in games and athletic sports and to carry on war. The following observations are recorded that they may incite some young Lubbock or JMcCook to find the cause and purpose of these wars. On the morning of June 20, 1883, 1 observed numbers of large black ants wandering excitedly over a back piazza of my house in Boxford, Mass- achusetts. More careful observation showed a dozen of their dead bodies scattered around, while two living insects were struggling in a desper- ate conflict. In some places dissevered legs and antennae were thickly strewn, while in retired nooks living ants were resting, either exhausted or skulking. I gathered over twenty corpses from the piazza and the ground. Some of these warriors, having mutually inflicted mortal wounds, had never relaxed their iron embrace, but lay dead in pairs. The conflict was not yet ended, and I watched one of these Homeric encounters. An ant had his antagonist's feeler in his jaws. The com- batant, thus held, twisted and turned to get his own mandibles upon feeler, leg, neck, or waist of his antagonist. He was, evidently, much unnerved by the other's hold, for these antennae seem as sensitive as the eyeball, and he was dragged about, resisting and struggling in every way, but all in vain. Finally, the antenna came off near the base and the two warriors parted. Single combats like this probably went on through the day, and a few occurred the following night, for in the morning I found more dead bodies. One wounded soldier died in my custody, and many, doubtless, in cracks and nooks, but the level floor seemed to be the main battle- field. Altogether T collected from the fight about seventy complete bodies or dissevered heads, which I preserved in a red pill box — the rather gaudy tumulus of this "Waterloo I In the same place on the morning of July 7, following, I found traces of another battle which was not yet finished. Again, July 19, there had been a battle during the night on the bare floor of a chamber at the opposite end of the house and upstairs. One morning in August, of the same year, I found traces of a similar battle in the cellarway of a neigh- boring house. — AV. P. Alcott, Bulletin, Essex Institute, 1897, p. 65 ANTS 145 A Study of Ants in the Laboratory The nest (formicary). Most species of ants readily adapt themselves to an artificial nest. After the first few weeks they become accustomed to their surroundings, and may live for years working and rearing their young, much as they do in their natural environment. Kellogg in his '' American Insects " describes several of the more commonly used formicaries. The large-sized insect- mounting cases serve admirably in this capacity. The case should be partitioned off into two or three rooms, by glueing strips of wood that reach nearly across. On the top of the walls of the case glue strips of Turkish toweling, so that air may pass to the rooms after the upper glass is in place. Choose two pieces of heavy glass of unequal size for the roof of the formicary, so that one piece will cover two rooms. Exclude the light from these rooms by placing blotting paper over the glass, and keep a wet sponge (finest texture) in each of the darkened rooms. All food should be kept in the light room, and should consist of small pieces of sponge cake, moistened with sirup or honey, apple, mashed nuts, dried fruit, and insects. Keep the sponges wet. In cool weather the food need not be clianged oftener than once in two weeks. How to obtain an ant colony. Dig up an ants' nest and take larvae, pupse, and woi-kers. If you cannot find the queen, release the captives and try other nests until success- ful. Carry the queen by herself in an envelope, and the young and workers with some earth in a cloth or paper bag. Upon reaching the laboratory, empty the earth and ants upon a board afloat in water; pick out the ants and young from the earth and place them with the queen in the nest.^ 1 An easy way to manage tliis is to scrape a hollow in the center of the pile of earth, put the queen in this, and cover it with a chip. The ants will then collect all the eggs and larvae into a pile, and they may be lifted into the nest with a spoon. 146 CIVIC BIOLOGY The carpenter ant (^Oamponotus pennsylvanicus) is one of the most satisfactory species to study. The colony lives in wood, and hibernating queens may be obtamed under the bark of stumps or logs in the fall or during a winter thaw. In general the logs and stumps in which they are found are not badly decayed. ]\Iost frequently queens are hiding beneath bark that may without difficulty be removed with the Fig. 76. Ants' nest This is made of an insect-mounting strip, 5 by 7 inches, \ inch deep, glued, with the two partial partitions, to the bottom glass. The top glass is cut so that one piece covers one, and the other two, of the compartments. A braided cotton twine is glued along the top of the frame and partitions to insure ventilation. The sponge, in the middle compartment, is kept moist ; and the living chamber, to the left, is kept dark when not under observation. Designed and photographed by the author fingers. The queen is curled up in a cleared space under the bark and may be alone or accompanied by several eggs, larvae, pupae, or workers. Having secured a queen of Camponotus pemist/lvammis, place her, together with her young, in a nest and carefully observe the beginning of an ant colony. Observations should continue for the remainder of the year and careful notes made to reen- force those taken upon ants in the field. Eggs. The queen may not lay for a month or more after ANTS 147 she has been brought into the laboratory. Note the uitervals during which eggs are laid. Describe the action of the queen and workers m regard to the eggs when the nest is disturbed. How soon do ants become accustomed to the careful interfer- ence of being observed ? Fill the sponges with water, one day hot, another day cold. What effect upon tlie apparent care of the eggs has a difference in moisture, temperature, and light ? Larva. The time taken for the eggs to hatch depends upon the warmth and humidity of the atmosphere. The time of in- cubation is about twenty days. The larvae are soft, footless grubs, the smaller end being the head. The presence of hooked hairs upon the bodies of the larvce explains how they are car- ried in bundles. Note that the larvae are helpless. They are not only fed by the queen and workers, but are carried about to places of proper temperature and humidity. With the aid of a lens observe how the workers and queen feed the larvse. The queen has food stored m her body, which enables her to live and feed her first brood without herself taking food. This fact probably accounts for the small size of the first brood, which is composed of workers, as compared with subsequent broods. The queen is relieved of all work when the workers appear. They feed her and the larvse and assume all work of the colony. Note that the larvae are of different ages, and that they spin cocoons as soon as they become full-grown. Are the lar- vae and pupae kept together? Ants have no regular places for their young ; even in the natural nest they are carried to places which offer suitable conditions. The pupa stage like the larval lasts about twenty days when the temperature is about 80°. Observe that the cocoon turns yellowish before the young ant (callow) appears. How long before the callows assume the duties of adult workers ? CHAPTER XIV SPECIAL PROBLEMS OF INSECT CONTROL The life histories of insects lie at the foundation of the whole subject of economic entomology, and constitute, in fact, the principal part of the sci- ence, for until these are clearly and completely made out for any injurious species, we cannot possibly tell when, where, or how to strike it at its weakest point, — S. A. Fokbes Control of insects by a community or nation must depend upon each citizen knowing the important species and actually doing his part. Insects are so small, tough, and hard to kill, and, above all, possess such powers of rapid dissemination and increase, that the problems of insect control are probably the most difficult hi the whole field of livhig forces. However, in the life history of a species from the egg, through the actively feeding larval stage, in the quiescent pupal condition, or in the adult, egg-laying period, it is generally possible to discover some tveakest point at which it may be successfully attacked. To work out these life histories, discover these vulnerable points of attack, and devise best ways and means is the function of our scientific experts ; but, in order that these discoveries accomplish their purpose, the people must learn and use the results. Organization for both research and information is so perfect that if any one wishes to know about an insect he has only to inquire of his State Experiment Station or of the United States Department of Agriculture at Washington. If the answer to his question is known, it will be sent to him prac- tically by return mail. If not, a special research may be ordered to solve the problem. 148 SPECIAL PROBLEMS OF INSECT CONTROL 149 As a nation we are paying about $25,000,000 annually for the discovery and dissemination of just this sort of informa- tion. If we are not " getting our money's worth," it is our own fault. One truth with regard to an insect which causes disease or levies a tax of often hundreds of millions of dollars on some staple crop may be worth the entire annual cost of tlie scientific departments of the government, as soon as the knowledge is put to use. With hundreds of experts working at these problems, knowl- edge is growing so fast that statements are likely to be super- seded before the ink of a book is dry. In order to keep up to date, every biological laboratory should have available for all students two important publications, the Monthly List of Piih- lieations and the Experhneiit Station Record., both issued by the United States Department of Agriculture. These will keep the student informed of every advance in our knowledge of insects, as well as of a great many other matters of interest. Make a list of the most important insects of the neighbor- hood, or those about which you wish to learn, and follow them through the indexes of the Expenment Station Record. Send to your State Experiment Station or to Washington for the bulletins you need, and, after studying them and collecting and observing your specimens in the field, mounting them so that they will tell as complete a story as possible, be ready to report your results to the class. Working independently and without consultation, let each member of the class prepare a list of the insects which lie thinks every member of the community ought to know in order to prevent annoyance, spread of disease, damage to household goods, stock or crops. This should be done after working through the laboratory types given in Chapters X-XIII, read- ing bulletins and books assigned, and studying the lists given below. After comparing and discussing individual lists, pre- pare a class list which shall include the most important local 150 CIVIC BIOLOGY problems, and one which the class can reasonably cover dur- ing the year, and then write the names on slips and let each draw a certain number, or distribute by individual preference, as the class may elect. As these studies progress they should be reported and freely discussed. Thus the biology class may be the organizing center for a better understanding of local insect problems, and enlist cooperation of homes and of boys and girls in the lower grades for more effective effort and better local control. The problem of insect classification. It is recognized that for an elementary and practical course the complete classification of insects is too difficult and would take too much time. The vast number of species, more than three hundred thousand, are commonly grouped into nineteen orders, and any student who is specially interested can find the subject fully treated in manuals. For all elementary purposes it will be sufficient to learn the names and characters of the seven more important orders. Every one ought to know what we mean by a "fly," a "bee," a "bug,". a " moth or butterfly," a "locust," a " beetle," a " lacewing." Since classification consists in gathermg into groups forms with similar structures and parts, we need to learn somethnig of the way an insect is constructed. To begm, take any large insect, a beetle or grasshopper, and work out all the apparent subdivisions of the body. Note the three mam subdivisions — head, thorax, and abdomen — and locate the breathing pores (spiracles) as indicated in Fig. 77. Insects, spiders, and myria- pods, instead of having one pair of nostrils, a wmdpipe, and lungs to which the blood is brought to be oxygenated, circu- late the air directty to the tissues by means of fine, elastic, branching tubes. These are known as tracheae, and these ani- mals are known, since this is a character of great significance, as tracheates. Contact insecticides — oil films on water for mos- quitoes, oil-emulsion or soapy sprays — depend upon clogging these fine breathmg pores and thus smothering the insect. SPECIAL PEOBLEMS OF INSECT CONTROL 151 Water will not do this, because the openings are protected against its entrance by oily secretions. Compare the effect of dipping an insect into water and into kerosene. Next, beginning at the head, study all organs and mov- able parts (appendages) : the eyes, feelers (antennse, replacing Head Prothorax Mesothorax Metathorax Abdomen Compmind Ey^ \ / , ' / Simple Eye/ Fore Wing Hind Wing Labium Mouth-Parts Ovipositor Fig. 77. External anatomy of the grasshopper ears and nose as sense organs, at least partly), mouth parts (very complicated, consisting typically of an upper and lower lip (labrum and labium) and two pairs of jaws (mandibles and maxillse), which move sidewise instead of up and down). Watch a caterpillar or grasshopper eat a leaf and see if you can discover why the jaws move sidewise. A study of mouth parts is again important with reference to methods of destroy- ing insects. Those that bite and chew can be killed by spraying 152 CIVIC BIOLOGY poisons upon their food plants or by mixing poisons with foods which attract them. Those whose mouth parts have been modified into an apparatus for piercing and sucking can be reached only by insecticides which kill by contact. The thorax is divided by rather conspicuous sutures into three parts named prothorax, mesothorax, and metathorax. Each carries a pair of legs ; that is, all insects have three pairs of legs. Wings may be present or absent. If two pairs, they are attached to the meso- and meta-thorax, and a single pair is usually attached to the meso-thorax. The insect wing is the most perfect flying mechanism in existence, and until man can match its structure for lightness and strength, he can hardly hope to solve completely the problem of flight. Note that insect wings vary in texture from the hard, shell- like structures, as in the fore wings of beetles and the leathery or parchment-like wings of grasshoppers and many bugs, to the transparent membranous wings of bees and flies. The abdomen is made up of a series of similar rings termi- nated by various organs concerned with reproduction, ovipos- itors, etc., sometimes modified into sharp stings. The life histor}^ of an insect also gives characters for classi- fication. With many insects the egg hatches into a worm-like maggot, grub, or caterpillar wholly unlike the parent, and later passes through a quiet stage (pupa or chrysalis) before becoming like the parent. In these cases the insect is said to show a complete metamorphosis (ineta^ " over " ; morphe^ '' form" — " change of form "). Name insects that you know, of which this is true. In other insects the egg hatches into something like the parent. To study this point, watch a nest of grasshopper or squash-bug eggs hatch. These insects are said to have an incomplete metamorphosis. In the case of a few insects — the San Jose scale, aphides, and some of the flies — the eggs hatch within the body and the young are born alive. SPECIAL PROBLEMS OF INSECT CONTROL 153 Of the nineteen orders the seven most unportant are : L Diptera (di-, "two*'; pteroUy "wing"). Two membranous wings, moiitli parts for piercing and sucking or for lapping ; metamor- phosis complete, larvie various in form and habit but always foot- less; maggots, wrigglers, etc. Examples: flies, mosquitoes, gnats ; 40,000 known species ; estimated number, 350,000 (Howard). IL Coleoptera (koleos, "sheath"; pteron, "wing"). Four wings, the front pair horny cases which cover the membranous hind wings ; mouth parts for biting ; metamorphosis complete, the larva a grub, with usually six legs. Examples : beetles, potato beetle, June beetle, lady beetle ; 100,000 known species (Galloway). III. Hemiptera(hemi-,^^ half ^^', />^eron, "wing"). Fore wings membra- nous, parchment-like or with horny bases and membranous tips ; hind wings membranous ; many wingless forms ; metamorphosis incomplete, the young resembling the adults, but wingless — the true " bugs." Examples : plant lice, scale insects, cicadas, lice, water bugs; 20,000 known species; probably 80,000 in all (Howard). IV. Orthoptera (orthos, "straight"; pteron, "wing"). Fore wings parch- ment-like, net-veined, hind wings almost always membranous ; mouth parts for ]>iting ; metamorphosis incomplete, the young resembling the adult, but wingless. Examples : grasshoppers, crickets, cockroaches, walking sticks ; estimated more than 10,000 species. V. Lepidoptera (lepis, "scale"; pteron, "wing"). Wings and body scale-clad ; mouth parts modified into a coiling, sucking tube, or absent ; metamorphosis complete, larva a cateri)illar. Examples : butterflies and moths; 25,000 known s}»ecies ((Jalloway). Yl. Hymenoptera (hymen, "membrane"; pteron, "wing"). Wings four, membranous, a few wingless forms ; mouth parts for biting and lapping ; metamorphosis complete, larva maggot- • like. Examples : bees, ants, wasps, sawflies, ichneumons ; about 80,000 known species ; estimated number, 300,000 (Howard). VII. Neuroptera (neuron, "sinew" ; pteron, "wing"). Wings four, mem- branous, usually net-veined ; mouth parts for biting ; metamor- phosis incomplete or complete ; larva usually unlike adult, sometimes aquatic. Examples : dragon flies, lacewings, etc.^ ^ This group is now subdivided into eight orders, among them the caddis flies {Trichoptera)^ dragon flies (Odonata), and white ants (Isoptera). 154 CIVIC BIOLOGY Most insects in the following lists belong to the above orders. Each represents a problem of interest to the com- munity and home, and the time will come when each citizen must realize that he has no moral right to breed pests which cause annoyance and damage to his neighbors. In reading the lists review what you have learned of each in previous years, especially running over the life history. It is convenient also to classify insects according to their point of attack or their food plants ; as, insects of the house- hold, garden, field, forest ; insects of the apple, grape, peach, etc. Many books for practical horticulturists and the agricul- tural bulletins treat them this way. Insects of the Household Flies : House fly, typhoid fly, or filth fly — Musca domestica ; small house fly — Homalomyia caniculaina ', stable fly — Stomoxys calciirans ; cluster fly — Pollenia rudis ; bluebottle fly or blowfly — Calliphora ery- throcepliala \ green-bottle fly — Lucilia ccesar-, fruit fly — DrosopMla am- pelophilia; cheese or ham skij)per — Piophila casei. Mosquitoes : Common domestic species, in rain barrels and stag- nant pools everywhere — Culex pipiens ; malarial mosquitoes — A nopheles macuUpennis, punctipennis, and crucians ; and the yellow-fever mosquito, throughout the South and wherever it is found breeding — Aedes calopus. Clothes Moths: Case-making clothes moth — Tinea pellionella; Southern clothes moth — Tineola bisselliella; tapestry moth — Trichophaga tapetzella; carpet beetle — Anthreniis scrophularioe ; black carpet beetle — Attagenus piceus. House Crickets — Gryllus domesticus and G. assimilis. Roaches: American cockroach — Periplaneta americana; oriental cockroach — Periplaneta orientalis ; German roach, Croton bug — Ectohia germanica. Bedbug : Common bedbug — Acanthia lectularia ; blood-sucking cone- nose — Conorhinus sanguisuga ; kissing bug — Opsiccetus personatus Lice: Head louse — Pediculus capitis; body louse — Pediculus vestimenti. Fleas: Human flea — Pulex irritans-^ cat and dog flea — Ctenoceph- alus canis ; rat fleas — Ceratophillus fasciatus and Pulex cheopis ; chigoe, SPECIAL PROBLEMS OF INSECT CONTROL 155 burrowing flea (chiefly tropical) — Sarcopsylla penetrans ; hen flea (bur- rows into the eyelids of fowls), Southern states — Xestopsylla gallinacea. This group was formerly classed with the diptera but is now usually given as an order by itseK, the Siphonaptera (^siphon, '' a sucking tube " ; a, " without" ; pteron, '' wing" — " wingless bloodsuckers"). White Ants : Termites — Termes Jlavipes. These are not ants, but belong to another order, the Isoptera (isos, "equal"; ptei^on, "wing"). Destructive to wood of buildings and furniture and even to living trees. House Ants : Red ant — Monomorium pharaonis ; little black ant — Monomorium minutum ; pavement ant — Tetramorium caespitum. Beetles : Larder beetle — Dermestes lardarius ; drug-store beetle — silrodrepa panicea; meal worms — Tenehrio molitor and T. obscurus; Indian-meal moth — Plodia interpunctella. The above are only a few of the more important household insect pests. Many others may be found by searching the house, and can be identified, if they present interesting local problems, by reference to the books mentioned at the end of this chapter. The fact that no headway is made in the fight with these enemies is due chiefly to lack of organized coopera- tion. One family exterminates them and is reinfested from a neighbor who does the work at some other time. Insects Injurious to Vegetation Orchard Pests : Codling moth — Carpocapsa pomonella; tent cater- pillars (apple-tree) — Clmocampa americana ; fall webworm — Hypfiantria cunea] cankerworms (spring — Paleacrita vernatci] fall — Anisopteryx pometarid) ; yellow woolly bear — Spilosoma virginica ; curculio beetles, weevils (apple — Anthonomus quadrigibbus ; plum — Conotrachelus nenu- phar; quince — Conotrachelus cratcegi; grape — Craponius incequalis; borer beetles ; round-headed apple-tree — Saperda Candida ; flat-headed apple-tree — Chrysobothris femorata (also attacks the plum) ; pear-blight beetle — Xyleborus pyri ; pear-tree borer — ^geria pyri ; cherry-tree borer — Dlcerca divaricata; peach-tree borer — Sanninoidea exitiosa; apple-twig borer — Amphicerus bicaudatus); sphinx moths ("humming-bird" moth) (plum — Sphinx drupiferarum; green grapevine — Ampelophaga myron); 156 CIVIC BIOLOdY scale insects (oyster-shell scale — Mi/tilaspis pomorum ; scurfy scale — Chionaspis furfurus; San Jos6 scale, Chinese pernicious scale — Aspid't- otus perniciosus, the worst fruit-tree pest on the American continent; cottony cushion scale — Icerya purchasi) ; apple-tree enemies (yellow- necked apple-tree caterpillar — Datana ministra ; red-humped apple-tree caterpillar — (Edemasia conclnna ; apple sphinx, or hawk moth — Sphinx gordius ; apple maggot, " railroad worm " — Rhagoletis pomonella^ ; enemies of small fruits (strawberry crown borer, weevil — Tyloderma fragrarkv. ; strawberry root borer — Anar.sia lineatellci', currant borer, American — Psenocerus aupernotatus ; currant borer, imported — u'Egerla tipuliformis ; grapevine root beetle — Pr tonus laticollis ; grape-berry moth — Polt/chrosis hotrana ; grape, gartered plume moth — Oxyptilus periscelidactylus ; rose chafer — Macrodaetylus suhsptnosuft); plant lice (aphids, grape — Phyl- loxera vastatrix; woolly apple louse — Schizoneura lanigera: cherry louse — Myzus cerasiy Vegetable, Grain, and Cotton Pests : Colorado potato beetle — Doryphora 10-Uneata ; striped cucumber beetle — Diabrotica vittata ; as- paragus beetle — Crioceru aaparagi ; June beetle (May bug in the South) — Lachnoste?'na fusca and others; flea beetles — Halticinl', blister or oil beetles — Meloidcc, cutworms — Noctuldoi (larvfe of a number of owlet moths or noctuids) ; sphinx moths (tobacco. South — PJdegethontius sexta: tomato — Phlegethontius quinqueniacidata) ; cabbage worm, imported — Pontia rapcv ; cabbage looper — A utographer hrasslccc ; cabbage and rad- ish maggot — Pegomyia h'assicce ; onion maggot — Phorhia ceparum ; cotton worm — Aletia argillacea; boll worm (corn-ear and tomato worm of the North) — Heliothis armigera\ army worm — Leucania unipuncta\ Hessian fly — Meri^ius destructor-^ corn-root aphis — Aphis maidi-radicis : grain aphis or " green bug " — Toxoptera gramineum ; chinch bug — Blissus leucopterus ; squash bug — A nasa tristis ; grasshopi:)ers (Rocky Mountain locust) — Melanoplus spretus; red-legged locust — Melanoplus femur- ruhrum Forest and Shade-Tree Enemies: Gypsy moth — Ocneria dispar (one of our most diflicult problems) ; brown-tail moth — Euproctischrys- orrhea (a national problem) ; elm-leaf beetle — Gahrucella luteola ; white- marked tussock moth — Notolophns leucostigma] cottony maple scale — Pulvinaria innumerahilis. Most of the Hymenoptera are highly beneficial insects, but among them are a few so injurious and troublesome that every member of a community ought to know them. These SPECIAL PROBLEMS OF INSECT CONTROL 157 are leaf-eating sawflies, aiid many others of less importance are borers and gall insects. Currant worm or slug — Nematus ventricosus ; pear slug — Eriocampa cerasi', rose slug — Monostetjia rosfe. Insects attacking Animals : Botfly (ox warble) — llypoderma lineata ; sheep botfly — (Estrus ovis • liorse botfly — Gastrophilus equi : horn fly — Hoematohia serrata ; screw-worm fly — Compsomyia macellaria. Beneficial insects. As it is said to '' take a thief to catch a thief," so it often takes an insect to catch an insect. From the usual study of injurious forms the impression is likely to be given that almost all insects are injurious. Yet even species which cause considerable damage may perform good service in cross-pollination of plants. The honeybee, our most useful species for this purpose, has the distinct advantage of winter- ing a large force of workers ready to cover the fruit bloom early in the spring, before our native, solitary bees have begun to breed in numbers. The problem of the honeybee and fertilization of fruit trees about the home or in the neighborhood is one which may well repay study. The question is. Are there bees enough to do the work ? The stone fruits are said to depend entirely on insect cross-pollination in setting fruit, and if the cherry, plum, and peach trees are not humming at some time during the bloom, there will be little or no fruit. Apples of some varie- ties and most pears are greatly improved in quality when cross-pollinated. For at least one hour on a bright, warm day while the trees are in bloom, with watch in hand, time and count the number of blossoms visited by bees per minute. Do this for all the differ- ent kinds of fruit accessible. How many men would it take to do the work of one swarm of bees of fifty thousand workers? Are there enough bees to pollinate the flowers and gather the nectar in the neighborhood ? Can you find any honeybees working on red clover ? 158 CIVIC BIOLOGY Test the practical value of insect cross-pollination by cover- ing a twig of cherry, plum, or peach with wire gauze or mos- quito netting during bloom. Compare the fruit of this twig with a similar one on the same tree which was not covered. Is there any evidence that orchards near apiaries bear better than others ? What can you learn of the comparative merits of different races of bees in your locality ? National problems. In the above list three insects merit special emphasis as presenting civic problems of national im- portance. All are species of almost unthinkable destructive power imported from the Eurasian continent, and until re- cently, at least, without their natural enemies. The San Jose scale was imported into the San Jose valley, California, in 1868, and has since spread over almost the entire United States. During this time it has probably killed more fruit trees than all other insect pests combined, and is now the most serious menace to the home fruit garden. Minute as is the insect, one pair may produce 'in a season 3,216,080,400. This at once shows how little chance a tree can have and how futile any treatment is which leaves even a few pairs alive. After ten years of experimenting with the various spraying mixtures recommended, the writer is obliged to state as his opinion that nothing has yet been discovered which will ex- terminate the San Jose scale from a tree. Hence it is of the utmost importance for the class to follow all announcements of discoveries as to effective methods of dealing with this insect. Make a thorough examination of your home premises and learn the history of the San Jose scale on. the place. How much damage has it done from year to year? How much has been expended in fighting it? What and how many trees have been killed by it? In connection with the field and laboratory work search for natural enemies, fungus or insect. Make a list of food plants upon which the scale is SPECIAL PROBLEMS OF INSECT CONTROL 159 found in your neighborhood. Compare results of different methods of combating it. From the data obtainable can you foretell the probable result? Will the home fruit trees be killed and the fruit industry confined to commercial orchard- ists who will care for their trees ? Gypsy moth. This pest is a European species. It was in- troduced into this country in 1869 by a Frenchman who was Fig. 78. Outdoor laboratory work Class inspecting a local nursery for San Jose' scale attempting to improve our native silkworms. Through acci- dent the insects escaped, but although the fact was reported, the grave danger was not realized until twenty years later. From a single nest in Medford, Massachusetts, the pest spread, slowly at first, and then like wild fire, over the towns and for- ests of New England. Millions of dollars have been expended in its control, yet hundreds of acres of forest have been de- stroyed. A report of 1897 says, "At the present time there can be little doubt that the extermination of the insect is 160 CIVIC BIOLOGY possible and that it will be only a question of a few years " ; but now, nearly fifteen years later, it is still gaining ground. Since a large portion of the year is passed in the egg stage, this is the natural time for extermination. The egg masses are conspicuous dark yellow splotches, and in a badly infested region may be found anywhere, — - on fence or stone wall, under porches, among dead leaves, — although the first and most common position is the trunk and branches of trees. The rapid fire which is sometimes sent through woods and under- brush to destroy other pests has no marked effect on these eggs. Attempts to remove the egg masses by scraping have proved equally ineffective, for eggs become scattered in the process and hatch as readily as ever. Saturating the egg clusters with the following mixture : creosote oil 50 per cent, carbolic acid 20 per cent, spirits of turpentine 20 per cent, coal tar 10 per cent, is the method of extermination recommended by state authorities. It is applied with a small brush. This treatment must find every egg mass, and therefore must be begun the instant the presence of the insect is known. The insatiable appetite of caterpillars makes so omnivorous a creature as the gypsy moth even more dreaded, for when one feeding grojind is exhausted, a fresh one over the fence or across the road is quickly attacked. Thus the pest moves on, leaving every twig stripped behind it. Every effort must be made to keep the pest within its pres- ent limits. The female imago does not fly ; therefore distri- bution is effected by the caterpillars which frequently spin down from the trees and fall upon passing conveyances, or by egg masses which are overlooked on lumber or are carried in various ways. Brown-tail moth. The problem of the brown-tail moth is one of even greater importance to the country at large be- cause of the greater rapidity of distribution. Both male and female are strong, swift flyers, and eggs may be deposited at SPECIAL PROBLEMS OF INSECT CONTROL 161 great distances from the original colony. Windstorms also aid in furthering the flight, and steam cars and trolleys trans- port these pests. Besides the injury to orchard, shade tree, and forest, the brown-tail caterpillar inflicts serious pain upon many persons. This is caused by fine hairs which pierce the skin, the irritation becoming severe enough in some cases to cause illness. A free use of vaseline will give relief. The brown tail cannot be controlled by an attack upon the eggs, since they are usually on the leaves and for a short time only. Spraying is em- ployed to destroy the swarm- ing caterpillars, but the most effective method is destruc- tion of- the winter nests. These are conspicuous on the tips of branches between August and iVpril. They may then be cut with pole shears, and must be ear ef idly coUeeted and burned. Parasites. The great aim in the attempt at control of any pest is to discover its nat- ural enemy. In the case of insects like the gypsy and brown-tail moths, a series of para- sites is necessary, for the parasitic insects restrict themselves to one stage only in the development of their host. The insect which attacks the egg takes no notice of the caterpillar, and the insect which attacks the caterpillar is never found upon pupse. Several native parasitic insects are known to attack these pests, and many have been imported ; but as yet the series is not complete and has failed of effective control. Fig. 79. Brown-Tail Moths Four egg masses and two moths laying, July 10. Photograph by Katharine E. Dolbear 162 CIVIC BIOLOGY Comparison of Gypsy and Brown-Tail Moths Gypsy Moth Eggs. August to May. On the trunks and branches and every- where^ especially on undersides and inner surfaces of objects. Masses. Light brown, long, broad, about the size of a silver quarter. 300-1400 eggs. Caterpillar. May to August. On wnJerside of leaves. Night feed- ers. Cluster in shelter during the day. Winter form. Egg. Full-grown. Two and one-half to three inches long. Rows of con- spicuous spots on the back — blue near the head, red on posterior part of the body. Hairy tufts on the sides. Pupa. Late July. Found in some places as e^g masses. Dark brown female larger than the male. Moth. Female, white with brown markings. Spread of wing, from two to three inches. Never goes far from pupa case. Male smaller, brown. Brown-Tail Moth Eggs. July. Seldom on trunk or branch. Generally on underside of leaf. Masses. Smaller than the gypsy, more elongated, brighter, red- dish brown color. About 300 eggs. Caterpillar. Hatched in August. On upper side of leaves in clus- ters. Day feeders. Winter form. Caterpillar in nest. Nest four to six inches long, composed of leaves and silk, contains about 250 caterpillars. Emerge in April, attack bud, blossom, and foliage of fruit trees, and then move to others. Fulh-grown. One and one-half to two inches long. Broken white stripe on each side of back, two red spots near posterior end. Hairy tufts on the sides. Pupa. Late June. Five eighths of an inch long. Dark brown, with yellowish hairs. Moth. Pure white. Female slightly larger, with conspicuous bunch of brown hairs at tip of abdo- men. Spread of wing, one and one-half inches. Night flyer, attracted by light. t t f 3a 5a HCT Oliver, del. PLATE i\. ADULT FEMALiiS OF Fl\ K IMPORTANT TICKS* CHAPTER XV ARACHNIDS. PROBLEMS OF SPIDERS, MITES, AND TICKS Prices would be higher, the demand greater, and the odium attached to ticky cattle at the stockyards removed. Pure-bred Northern cattle could then be brought into the South to improve the native breed, without danger of death from Texas fever ; Southern cattle could enter the show rings of the North without restriction ; and the total cost of tick extermination would be far less than the amount saved in the first year after it had been accom- plished.— John R. Mohler, 1914 Closely allied to insect problems are those of the arachnids. This group includes scorpions, spiders, mites, and some of the ticks. Interesting as they are, scorpions and spiders are far sur- passed in economic importance by the insignificant mites and ticks. Among the latter are the cattle tick (carrying the germ of Texas fever), the sheep scab mite, mites which attack poultry, and the red spiders and harvest mites which infest vegetation. Since arachnids are often mistaken for insects, compare any common insect and spider, noting their similarities and dif- ferences. Make a diagrammatic sketch of each. Similarities. Both insects and araclmids are ringed or jointed aninials. Both are' tracheates, though a few of the arachnids, particularly spiders, have also pulmonary sacs. Differences. These will be found in the relation of head and body, the number of legs, presence of antennae, com- parison of palpi. * Five species are shown, enlarged and natural size. 1 and 1 a, adult female cattle (Texas-fever) tick ; 2, growth stages and variations in color of this tick ; 3 and 3 a, Rocky Mountain spotted-fever tick, adult female ; 4 and 4 a, female dog, or wood, tick ; 5 and 5 a, female European dog tick ; 6 and 6 a, female chicken tick. (Reproduced from plates issued by the United States Department of Agriculture and the United States Public Health Service.) 163 164 CIVIC BIOLOGY The larger arachnids, in spite of their bad reputation and terrifying appearance, are comparatively harmless. Even those of the poisonous varieties, tarantulas and scorpions, make no attack upon man un- less frightened or mo- lested. Their economic importance is not con- sidered great, though since they are insectiv- orous, they may be dis- tinctly beneficial. The smaller arach- nids, mites and ticks, cause great destruction of vegetable and animal life. They are charac- terized by an unseg- mented body, the abdo- men as well as the head being joined to the tho- rax. While we must not overlook the service of some species as scav- engers, we are con- cerned much more with them as })arasites upon living animals and plants. Red spider — Tetra- nychid(£i " four-clawed." This greenhouse pest is found both indoors and out, and on various plants and trees. It is one of the commonest families, containing sixty species. The red spiders are most trouble- some in times of drought and are found chiefly on the underside Fk 80. Ilarvestineii clearing the plant lice from a grapevine Photograph by the author PROBLEMvS OF SPIDERS, MITES, AND TICKS 165 of leaves. So minute are they that a smgle one is scarcely visible to the naked eye, and they are often not noticed until the plant is badly infested. They pierce the surface of the leaf and suck its juices, and very soon the plant begins to appear yellow and sickly. When it is practicable the garden hose will exterminate these pests. Under other conditions spraying with fish oils or soap solution is effective. Clover mite — Bryobia pratensis. As the name indicates, these mites are found chiefly upon clover, but also on apple and peach trees, cottonwoods and arbor vitse, and even on boards, stones, and fences. During the fall and winter they appear also on plum, almond, poplar, and elm trees, and frequently leave vegetation entirely and become very troublesome in houses. Of species found upon animals, there are some which can- not be considered a real menace to health, yet they are ex- tremely irritating and troublesome. The most common of these are harvest mites and wood ticks, the former being one of the smallest of mites, a mere pin point of red, and the latter one of the largest of ticks, reddish brown, a quarter of an inch in length and swelling, as it feeds, to the size of an olive. Harvest mite — Tromhidium holosericeum. When in the larval stage, these are the ''chiggers" of the Middle States. During early summer harvest mites will be found on grasslands and sandy slopes, or in the woods. They can be seen most easily in July, when the eggs are being laid, and that is the time also when they begin to attach themselves to any passing animal. The creatures of the woods, especially moles and hares, are sometimes literally infested with them, and dogs, cats, horses, and cows often show signs of intense itching from them. In some localities there are few people who have not felt their presence. Sulphur ointment or friction with a cloth dipped in benzine or strong alcohol will give speedy 166 CIVIC BIOLOGY relief, if applied soon after exposure and before the mites have become embedded in the skin. Itch mites — Sarcoptes scabiei (scabere, "to scratch "). These mites have long been a terror to man. They multiply at the rate of 15,000,000 from a single pair during the season, are easily passed from one animal to another, and are extremely difficult to control. There are many varieties of itch mites, differing in size ac- cording to the thick- ness of skin of the animal they attack. The pig, horse, wolf, goat, camel, sheep, dog — each has its own variety (de- creasing in size in the order here given) and the human mite is the smallest of all. The punctures made in the skin by mites are soon covered with a crust, the eggs bemg found beneath it. The human mite is best held in check by warm baths with free use of soap followed by an application of sulphur ointment. The same treatment is equally good for dogs. Sheep-scab mite. — Psoroptes communis (var. ovis). This para- site is distributed over the entire world and has proved so destructive that most countries have passed laws to prevent its importation or spread. With intelligent cooperation in the use of precautions and methods of treatment now understood, sheep scab could soon be eradicated. Fig. 81. Egg cocoons of spiders on burdock Photograph by Dr. J. P. Porter PROBLEMS OF SPIDERS, MITES, AND TICKS 167 The poultry mite — Dermanyssus gallince. This is a vicious- looking creature when seen under a microscope. In color it varies from yellowish white to blood red when fully gorged. Its presence is sometimes not suspected, for it is a night worker, and during the day it disappears into cracks, especially in the ceilmgs. If extremely numerous, adults may be found on the fowl, but generally not even the indications of their punctures are visible and only the condition of the poultry shows their existence. There is danger of this mite being carried to the stable, if near by, and the effect upon horses is sometimes serious. Absolute cleanliness in the henhouse is the price of freedom from this pest. The Rocky Mountain spotted-fever tick. — Dermacentor ve- nustus. The germs of spotted fever are carried from native wild animals to man by the bite of this tick. The life history of the tick consists of four stages — the egg, " seed " or larva, nymph, and adult — and occupies from one to three years. Failure to find a host during any of the three active stages results in death of the tick by starvation, and the discovery that earlier stages are largely dependent on the rodents of the region has resulted in a plan of cooperative effort to ex- terminate rodents and ticks together. Since most of the host species are destructive to agriculture, the work is doubly worth doing. " Cooperation by all landowners in a district is essential to success of any extensive campaign of rodent destruction." 1 It has also been observed that sheep rid land of this tick, and this suggests that they might prove useful against chiggers and other ticks. Cattle tick — Margaropus annulatus. The germ of Texas fever is now known to be carried by this tick. The loss to the South as a result of this disease has been estimated by the "^ Clarence Birdseye, " Some Common Mammals of Western Montana in Relation to Agriculture and Spotted Fever." Farmer'' s Bulletin No. 484. AVashino:ton, 1912. 168 CIVIC BIOLOGY govemmeiit to be |63,250,000 annually. Texas fever does not become established in the North, because the tick cannot survive the winter; nevertheless it frequently appears there. Northern cattle have been attacked by it as early as thirteen days and as late as ninety days after the tick-bearing cattle have passed tlirough the locality.^ Eight species of ticks have been found on cattle in this country, but only Margaropus annulatus carries the germ of Texas fever. It may be distin- guished readily from the other seven by its tiny reddish-brown head, contrasting with its dull yellow or even olive-brown body, and by its shape and size. The body is broadly oblong, sometimes reaching fifteen millimeters in length, and shows irregular markings of yellow. Notice differences between Margaropus annulatus and comparatively harmless ticks com- mon on cattle (Plate IV). Dog tick or wood tick — Dermacentor electus, Aristotle calls the wood tick, dog tormentor. Whoever has experienced one on himself knows well the firm grip which it takes, and appreciates the name. Force in removing the tick results either in pullmg away the body and leaving the head still attached, or in carrying away a bit of flesh with the head. The better way is to touch the tick with a drop of kerosene or turpentine. It then loosens its hold and is easily removed. These are only a few of the mites and ticks. Frequently one comparatively unknown is discovered to be the cause of some baffling disease or a possible check to some pest. Your observations now may assist in the future. Keep a record of each new parasite you find — insect or arachnid ; note name of specimen, date, locality, host (plant or animal upon which it is found), and any facts likely to be useful. 1 This necessitated drawing the quarantine line of 1891 across the conti- nent from southern California to southern Virginia. This line has been pushed southward since active tick eradication was begun in 1906, and coop- eration of stockmen must eventually relieve the entire South. The problem is one for serious study in all schools within or near tick-infested territory. CHAPTER XYI AMERICAN MAMMAL rilOBLEMS Each form of animal or plaiit .should be looked upon as an experiment in making a machine which shall best tit its environment and most effectively do the work required of it. The fit live ; the unfit are relegated to the bio- logical scrap heap, that is, become extinct. Care of offspring and protection from the elements are prime factors in fitness to survive. Mammals excel in both of these functions and characters, and while the feather is as light and perhaps more beautiful, hair is tougher and stands harder wear, and milk carried by the mother is a safer provision for the young than food packed in the shell of an egg. Above all, the intelligence which fashions adaptable protection from the elements, clothes and liouses, caps the climax of purely biological fitness. Mammals. This group, to which man himself belongs, ranks highest in the scale of animal life. Its various forms dominate easily sea and land and yield only to birds domhi- ion of the air. Every one knows a bird at sight, but, unlike this compact group, mammals differ extremely in structure from fishlike porpoises and whales to birdlike bats. In gen- eral, hair is as characteristic of mammals as feathers of birds ; and aside from a few freak forms, like tlie Australian duck- bill (^Omithorpichus paradoxus, '' bird -nosed paradox "), which lays eggs and incubates them like a bird, mammals agree in nourishing the young with milk. Among the more important problems relathig to American mammals are the following: 1. Extermination of predacious forms as the continent has been opened up to settlement — panthers, bears, lynxes and wild cats, wolverines, wolves, minks, skunks, and weasels. 2. Utilization of native wild animals — bison, elk, moose, deer, antelope, mountain sheep and goats, hares and rabbits. 169 OPOSSUMS AND KANGAROOS Fig. 82. Orders of nianiinals, with habitats 170 AMERICAN MAMMAL PKOBLEMS 171 These have been an important source of food during the early settlement of the country. 3. Trapping fur-bearing mammals — beaver, otter, marten, sable, badger, muskrat, moles, and others. 5. Efforts to prevent the total extinction of valuable species. This last feature of the American problem has been late in developing. Our destruction of animal game resources is commonly spoken of as wanton, and in many instances this is undoubtedly true. Still the problems are not so simple as they often appear ; for example, thousands of bison were shot for the mere sport of shooting, and the species is now practically extinct in the wild state. This seems a great waste, but it is impossible to use the same range for both bison and domestic cattle, and cattle are much more valuable. The bison herds swept the range cattle with them in their migrations and strewed settlers' fences over the plains. When full-grown they are not amen- able to ordinary means of control and probably could not be profitably domesticated. Even tame buck deer and bull elk are dangerous animals. Rearing the bison in specially fenced preserves is quite a different matter, and has proved — at, present fancy prices for robes and heads — a profitable indus- try. Both the United States and Canada have undertaken to thus safeguard the species from extinction, and the American Bison Society has been recently organized to make sure that the largest, and in many ways most picturesque, American mammal shall never entirely disappear from the earth. Those in charge of zoological parks and private forest preserves, as well as of the extensive national forest reserva- tions, are all making preservation of native animals a strong feature of their work. Many states are also beginning to legislate to prevent extermination of valuable animals. Sev- eral states derive considerable revenue from hunting licenses, and, in order to attract sportsmen, must maintain the supply 172 CIVIC BIOLOGY of game. Wild deer are beginning to be seen in eastern ]Mas- sachusetts, the state allowing but a single week for hunting them and paying all damage which they cause to crops. These damages are increasing, however, so fast that it is a serious question whether such an animal should be allowed to range at large in a state not possessing extensive tracts of waste land. State forest reservations, private hunting preserves, and spe- cial parks will probably solve the problem in such a manner that the species will be preserved and the people permitted to see and enjoy them in their native haunts, while promiscuous damage is prevented. The preservation of the fur seal has come to be an inter- national problem which is engaging in its solution the best ex- perts of England, Russia, Japan, and the United States. There is thus a good chance of saving a great industry to the inter- ested nations and a number of fine species of seals to the world. As the animals have been trapped off, the price of furs has steadily advanced, until the rearing of fur-bearing animals — notably the silver fox — is becoming a paying industry. At present prices it ought to be possible to rear many of our fur- bearing animals at enormous profit. " The beaver,'' says Pro- fessor Shaler, '' particularly the North American form, offers a most attractive opportunity for a great and far-reaching experiment in domestication. On this continent, at least, the creature exhibits a range of attractive qualities which is ex- ceeded by none other in the whole range of the lower mam- malian life.'' Here is a new field of biological interest, experiment, and human advance in control of animal life which ought to appeal to boys who live on farms affording opportu- nities for such work. Methods of caring for the animals in confinement or under control may be learned to advantage from zoological gardens ; and anything in the way of local " deer farming " or '' fur farming " should be studied and reported on by interested members of the class. CHAPTER XVII THE RAT PROBLEM The rat is the worst iiiaiiimalian pest known to man. Its depredations tliroughout the world result in losses amounting to hundreds of millions of dollars annually. But these losses, great as they are, are of less importance than the fact that rats carry from house to house and from seaport to sea- port the germs of the dreaded plague. — David Laxtz, ''The Brown Rat in the United States," p. 9. Bulletin No. 33, Biological Survey, United States Department of Agriculture The smell of mice shall be in their nostrils and they shall die. — Old saying To pay 11,000,000 for the last pair of rats on the North American continent, after the Panama Canal is cut through, and every harbor is properly sea-walled, might be money well expended. The warfare which has been going on for thou- sands of years might then be terminated in at least one conti- nent — and may not all good Americans unite in the hope that ours may be the first continent of which this is true ? The failure of all attempts to deal with this vile enemy may be traceable to lack of a vivid realization of what the " last pair " may do in the way of increase. The brown rat may breed five times in a season and have from 6 to 23 young at a litter. Allowing 8 young, the increase from a single pair in a season may amount to 880 ; and if we figure 10 in a litter, this number is increased to 1250. In three years with only 6 young in a litter Lantz has computed the possible increase at 20,155,392. From these data it is clear that any scientific method of dealing with this problem in any home or locality must catch the last pair, and also, under existing conditions, insure catching the first pair as soon as it comes. 173 174 CIVIC BIOLOGY Damage annually caused by rats has been figured for several countries as follows : Denmark $3,000,000 France 40,000,000 Germany 50,000,000 " England 73,000,0001 United States 100,000,000 2 This estimate of 1100,000,000 worth of grain is based on the amount actually eaten by rats, and Lantz maintains that they destroy and pollute " fully as much as they consume." But a Fig. 83. Common brown rat and mouse Photograph by the author damage tax of |200,000,000 levied annually on cereal crops is by no means the whole story. The poultry industry yields 1600,000,000 annually, and rats take an enormous toll of eggs and young chicks. " I have known them to take nearly all the chicks on a large poultry ranch, and in the same neighbor- hood and over a large territory, to destroy nearly 50 per cent of the season's hatching " (Lantz). The writer learned of an instance of a large rat killing and carrying away an entire brooder lot of over two hundred newly hatched chicks in a single night. Ducks, turkeys, pigeons, game, and song birds 1 Great Britain and Ireland, rural damage, and does not include losses in towns and cities and that inflicted upon shipping. 2 For destruction of grains only. THE RAT PEOBLEM 175 suffer likewise from their attacks. Finally the rat is the primary boast of trichina which causes so much damage and loss in the raising of swine. One of the prime requisites in all such industries, if they are to be conducted with safety and success, is rat-proof construction. The depredations of rats on fruits and vegetables, bulbs and seeds of all kinds, and all manner of merchandise, meats, and stored provisions are too well known to require more than passing mention.. Buildings are damaged, water pipes gnawed Fig. 84. A small night's work for a rat Eleven chicks have been killed and dragged into the hole and three bitten so that they died. Photograph by the author and buildings flooded, the insulation of electric wires de- stroyed, which, together with matches carried into their nests and ignited, cause numerous fires. " It is conservative to place the entire yearly loss to the people of Washington from rats and mice at $400,000 " (Lantz). For Baltimore, Lantz esti- mates the yearly damage at $700,000 ; and for cities in the United States of over 100,000 inhabitants these studies would indicate an annual loss of |20,000,000. Black death, the bubonic plague, beginning in China in 1334, swept westward over Europe, and in that single epi- demic killed, it is estimated, 25,000,000 people in Europe 176 CIVIC BIOLOGY alone. One half the people of Italy were killed by it. Whole villages and towns were left without a livuig inhabitant, and cattle ranged at will among the unharvested fields. In the recent epidemic it is estimated that the plague has killed hi India, up to 1907, no less than 5,250,000. It has gained a foothold in this country, but San Francisco, hi the most thrill- ingly interesting civic effort ever recorded in human history, and with the best assistance the national government could give, stamped it out after taking a meager toll of seventy-seven lives. " He died of the plague and all my family with him. I have no home or wife or relation to go to so I will take no leave this year." — Keply of a native sol- dier in India to a question about his brother. Bubonic plague in man is entirely dependent on the dis- ease in the rat. The infection is conveyed from rat to rat and from rat to -Lantz, quoted from "Etiology Fig. 85. Lead pipe gnawed by rats This flooded a house and fortunately caused only $7 damage man solely by means of the rat flea. and Epidemiology of Plague," p. 93. Calcutta, 1900 Thus a bacterium, an insect, a mammal, and man are bound together in a biological relation which has cost the world hundreds of millions of human lives and centuries of misery and horror. At last modern biology has discovered this relation, and the fact that an intelligent people can learn and realize its truth and act together for the common good has made the difference between the San Francisco epidemic and that of India— 77 hves to 5,250,000. If the rat did no other damage, is not this sufficient reason to induce every citizen of a civilized community to exterminate rats from his premises ? THE RAT PROBLEM 177 It lias l)eeii said that " of all liigliways a rat loves a drain the best." Ovir whole sehenie of sanitation depends apon the principle of washing all filth and disease germs into onr sew- ers. Here then we have an animal which wallows and crawls and swims in this filth and nightly distributes it over exposed foods, merchandise, markets, and homes. In this way rats are often responsible for persistent local epidemics of any disease whose germs are washed into sewers, — typhoid, diphtheria, scarlet fever, and many others. These facts, together with common decency and intelligent cleanlmess, are again suffi- cient reasons for extermination of such filthy pests. On all three counts, therefore, — general destrnctiveness, carriers of Black death, distributers of disease and filth — rats deserve absolute extermination. They were formerly con- sidered valuable as scavengers, but modern methods of sani- tation are thwarted by them, and these have rendered their further services in this line doubly undesirable. The simple duty of every citizen is to exterminate the rats from his own premises. Modern methods — traps, poisons and poisonous gases, concrete and rat-proof construction — render this entirely possible, and at a fraction of the cost which the presence of the pests yearly entails. All methods of driving rats away, scattering them among the neighbors, accomplish no real good and are besides uncivic. Trapping is at once the safest and, for boys, the most edu- cative method of keeping a home free from rats. It is no more expensive and much more interesting to keep traps set all the time than to allow them to be lying idle. If we could fire a pistol that could be heard across the continent, and from that day on have all the boys of the country keep all the idle rat and mouse traps set and baited in the most likely places about their homes all the time, the battle would be nine tenths won. Stores, mills, stables, factories, depots, and wharves could then deal with their own problems effectively 178 CIVIC BIOLOGY and not have the constant stream of rat and mouse immiscra- tion from surrounding homes. To work for days and finally outwit a wise old rat and catch him often gives one a game and a story almost as instruc- tive in animal cunning as that of old Lobo Rex Currump?e. Being chiefly nocturnal, and living, as they do, in the total darkness of burrows and drains, rats sense danger mainly by smell, and the smell of man, his archenemy, will scare a rat away from a trap recently handled. But leave the trap, care- fully covered with earth or bran or loft sweepings, in a natu- ral runway or at the mouth of a burrow a week, the man scent disappears, the wisest old rat has a moment of absent-mindedness, and the last one " puts his foot in it." A study of rat traps is interesting, but is apt to suggest that their manufac- turers are chiefly concerned with making something which will not exterminate their business by catching rats. All authorities to the con- trary, notwithstanding, the writer, after ten years' active study of the problem, would discard all rat traps which depend upon being baited, except the cage or box traps to be described below. Give him an old-fashioned steel spring trap, and, by keeping it set year in and year out, he will guarantee, with the aid of other methods to be described, to catch the last and the first rat on any home premises. This does not apply to mouse traps which require baiting, and which, if kept baited and set all the while, insure catchmg the last and first mouse in any house or barn. If the focal method described below cannot be adopted, a French cage trap may prove of some use about a home, if it is Fici. 86. A durable and effective trap THE KAT PROBLEM 179 kept well baited all the time, and open. As soon as it is noted that the rats are feeding in it freely, close the trap end and make a catch. Poisons are rather " unbiological " and require some care in handling. The Department of Agriculture has recommended barium carbonate as the cheapest and safest poison to use for rats and mice. It is tasteless, and in the small quantities used is not dangerous to domestic animals. Another advantage is that it is slow in acting and the vermin leave the premises to die. Mix oatmeal with one eighth of its bulk of the poison into a stiff dough with water, and place a teaspoonful in a Fig. 87. A good design for a runway trap These traps were so poorly made that they were likely to fly to pieces when snapped, and never caught a good-sized rat for the author until he had put in a row of tack points along the end of the bottom board plate about likely places. Or moisten a slice of bread and rub in a quantity of the barium powder on both sides, spreading butter over it ; cut into inch cubes and place in the runways. Or mix two teaspoonfuls of the barium with an egg, thicken to a stiff paste with oatmeal, corn meal, or bread crumbs, and distribute as before. Pieces of raw Hubbard squash with the poison rubbed well into all the cut surfaces, and with cuts made in the flesh and filled with it, make excellent baits. It is well to change the kind of bait and at first to feed freely with the same material unpoisoned, and even then, according to the writer's experience, you will not succeed in fooling the 180 CIVIC BIOLOGY last old wise ones. Above all, use clean scalded dishes and utensils and avoid all possible taint of man-smell on the bait. Arsenic is one of the most common ingredients of rat poisons and has the advantage also of being tasteless and of causing intense thirst so that the animals leave the premises m search of water. It may be used in combhiation with any of the baits described above. In mixing with corn or oatmeal take one twelfth by weight of the poison. In putting the above poisons in houses or barns be sure to have no water accessible inside the buildings ; but leave doors and windows open, and, if a pan of water is sunk in the ground in the yard, rats and mice Fig. 88. The poison box The inner box, where the bait is put, should he about 4-6 inches smaller in hori- zontal dimensions. The strip (^ + X 1 inch, is nailed all around the bottom of the larger box to prevent scattering of iwisoned material. Bait with pieces too large to be carried out. Leave holes in lower corners small for rats to enlarge in numbers may be seen dying and dead around it. Tliey even lose all fear of man and crawl to the water to drink in broad daylight, and commonly remain at the water until they die. To destroy rats on farms. Each evening when tlie cows are milked l>lace a little fresh milk in a shallow pan where the rats can get it. C'ontinue this for a week or more until the rats get bold and impatient to get at it. Then mix arsenic with the milk and await results. This plan is said to entirely clean a barn of rats. — Quoted by Lantz from E. H. Reihl, in Colman's Rural World, January 29, 1908 Strychnine acts so quickly that there is danger, when used about buildmgs, that the animals may die in the walls. In THE RAT PROBLEM 181 other places it may be used very effectively, and still, on account of its intensely bitter taste, it seldom catches the sly old ones. Stryclmized grain used in poisonmg sparrows is equally effective for rats and mice (|^ oz. strychnia sul- phate dissolved in l pint of boiling water, thoroughly stirred into 2 quarts of cracked corn or wheat, dried and labeled and stored safely for use). The writer has been told of clearing a barnyard and large stable by first feeding the rats with raw, unbroken eggs, then substituting eggs heavily charged with strychnine, the crystals of the poison being pushed through small holes in the shells. The ground near these eggs was described as '' strewn with dead rats." Phosphorus pastes commonly sold as rat and mouse poisons cannot be recommended, as they are too likely to cause fires. The other ingredient, glucose, is likely to be leached or w^eath- ered away, leaving the phosphorus strong enough to ignite spontaneously, and lumps of the material may be carried by rats from perfectly safe places — in a cemented cellar — up into the nests anywhere in the building. Even fields of grain have been fired in this way. Fumigation with poisonous gases is perhaps the most effec- tive method of dealing with vermin that burrow. It is such sport to absolutely exterminate rats from fields, dumps, poultry yards, and cellars that the game is worth the expense. C arbon bisulphide is the agent most commonly u sed. Moisten a tuft of cotton or a rag the size of an egg with about a table- spoonful of the bisulphide, push it down the hole, and tamp tightly with earth. If the hole is dug out, and remains inhabited, — which can be ascertained by filling the mouth with earth a few times, — repeat, using a double dose. Carbon bisulphide is poisonous to breathe and is not only highly inflammable but very explosive ; therefore keep all lights away while using. What we have called the ** focal " method of dealing with civic pests consists in discovermg something which attracts 182 CIVIC BIOLOGY them above everything else. This is a method of attracting (focusing) all vermin to a particular place, and is diametri- cally opposite to all the common devices for " driving away " or scattering our pests among our neighbors. When we find something which will attract every fly, mosquito, flea, rat, English sparrow, stray cat to a certain spot and catch and kill them there, the work of control or extermination will be easy. A dog is a natural focus for every flea about the premises. Lather him with soap daily or once a week for a few weeks and every flea will be exterminated. The natural focus of any animal is its preferred food, and for rats and mice about the home this is the granary, feed room, pantry, or storage cellar. It is only necessary to make these absolutely rat and mouse proof, — easily accomplished now with cement, sheet metal, or wire net, — and then leave no food exposed outside these places, and, to all practical intents and purposes, we have our premises rat proof. We can then easily establish a focus which will catch or kill every rat or mouse which comes to us for food. Take the example of a home which has a horse and cow and poultry. Each place will present its own problems, but the following "scheme will apply to all sorts of conditions. If possible, have all feed for poultry and stock kept in a rat- and mouse-proof feed room. The wall of this room is tight, preferably steel lath and cement, except a space six inches high by one foot long in one of the corners against the outer wall of the barn. This space is closed by both heavy wire net of one-quarter-inch mesh to exclude all rats and mice, and also with fine wire gauze to keep out all in- sects. Rats and mice seek their food by smell, and this opening will focus to that place all the animals as they come to the premises, if no other food is accessible anywhere else. Keep the bag of Spratt's dog biscuit and the poultry scrap meat and a bag of sunflower seeds near this hole, and if rats THE KAT PROBLEM 183 and mice are coining in rapidly, as they often do in the fall, keep and feed well for a while a female rat in a wire cage against this opening. Now bore a hole through the side of the barn close to this corner. It is well to make this hole one inch in diameter and allow the rats themselves to en- large it so that it will be an actual " rat hole." Fasten securely a cage trap so that all rats and mice which enter the barn must do so through this trap. If all doors and windows are properly screened and kept closed and all holes are stopped up, this will insure catching the first rat or mouse that comes and thus prevent even the beginning of breeding foci about the premises.^ Possibly enough expense is incurred annually in many towns and cities and enough effort expended to effectually exterminate rats and mice, but the work is not organized. A may exterminate the pests from his place in October, B from his in November, C from his in April, and all three of their premises be infested again for the season's breeding, the work of one driving the old cunning rats over to neighbors. We have effective methods enough to accomplish the com- plete extermination with a small part of the effort and ex- pense wasted by our communities annually. What we lack is effective organization. Rats and mice tend to leave buildings in the spring and migrate back to them in the fall. Since our experience with rats and the plague in San Francisco, and in view of the fact that other cities or even towns may be called upon at any time to fight the plague, every home ought to do its part, and every community ought to be able to extermi- nate its own rats. The disease to-day is widely distributed, 1 An even more serviceable trap which will set itself and thus catch a continuous stream of animals may be made by any ingenious boy, possibly in connection witli the manual-training work. If vermin are likely to gain access to the building by other openings, it is well to have an entrance to the trap inside the building as well. 184 (^IVIC^ BIOLOGY and no one can tell where some migrating rat will carry it next. Thus while other considerations of damage and general public health make this Avork expedient, danger from plague renders it imperative. People who do not know have no right to opinions in such vital matters, and the time must come when the ignorant and negligent shall not continue to vitiate the best civic efforts of our towns and cities.^ Cannot the biology class in the high school or local acad- emy, assisted by the boys of the upper grades, supply the intelligence and generalship, and bring about the cooperation and organization of the civic effort to render the work of extermination effective — even to the last pair in the town, or the lirst pair that migrates to it ? Might not this work alone go far toward repaying to the com- munity the cost of public education ? Mice should be dealt with as thoroughly as rats in all these campaigns, and they possess so little cunning that they can easily be extermmated from any premises. Aside from nuisance and damage caused by mice the theory has been advanced that germs of pneumonia become more virulent on passing through the mouse, and thus cause severe and often fatal infections. Fiii. bU. I'lit^ only rat this trap cauglit A poor design — wholly dependent on bait 1 The thing to do, brothers, is to get together; cooperate with the health officers ; lend them your moral support as freely as you have your material aid ; and, above all, do your part in suppressing the scoffer, the man who laughs in his ignorance, and who in that ignorance wants to trifle with a situation like this. Remember, in these matters each one of us is in a measure his brother's keeper, and let us show this man that if he is not willing to do his part, we are not only willing to do ours, but we are going to see that he does his, whether he wants to or not. — San Francisco Report, 1909, p. 254 THE RAT PROBLEM 185 Practical Problems The practical laboratory work of this section shall consist in actually exterminating rats and mice from your home premises. Make a complete survey and locate every rat hole in the ground and in the walls of buildings, and draw a careful diagram with all holes located. Stop all holes with earth and mark on your diagram in red ink all that are reopened. Locate on your diagram also rooms or buildings of rat-proof construction. Make as complete a collection of rat and mouse traps as the neighborhood affords. It will be well to have each member of the class bring in all the traps he has used at the end of this campaign, and compare and discuss the merits and demerits of different traps. Devise and construct a better rat trap than any used. Write a brief statement of your own experience in clearing your home of these pests. CHAPTER XVIII FUNGI : BACTERIA, YEASTS, MOLDS, MILDEWS, RUSTS, SMUTS, AND MUSHROOMS Although the great mass of material phenomena elsewhere had been brought into apparent orderliness and system, here was a region in which the unscientific imagination rioted in mystery and extravagance. The pene- tration of this realm of obscurity by the discoveries of bacteriology gave the human race for the first time in its history a rational theory of disease, dispelled the myths of spontaneous generation, and set the process of decay and kindred phenomena in their true relation to the great cycle of living and nonliving matter. The new conception of the microscopic underworld which bacteriology brought into biologic science must be reckoned as a conspicuous landmark, and, in so far as it has changed the attitude of man toward the universe, should be regarded as one of the most important triumphs of natural science. — Jordan, "General Bacteriology," p. 23 The role of fungi in the life of the world. Saccardo's " Syl- loge Fungorum" has described to date 66,615 species of fungi. This means that somewhat more than one fourtli of all the plants known to science belong in this group, and over 1000 new fungi are being described each year. Food supply is the vital problem of plants, animals, and man, and in order to appreciate the position of the fungi in nature we must study the continual flow of food material and try to understand how the world is fed. Fungi lack chlorophyll ; hence they are dependent for food upon other plants and upon animals. Some tend to be omnivo- rous, like the common molds of the household, and take almost any food that comes their way, while others are close feeders, living on some one animal or plant or even upon certain organs, tissues, or substances produced by their necessary 186 FUNGI 187 host organisms. The great work of fungi in nature is thus to break down organic matter and return the elements to Mother Earth, that they may be caught up in the circle of food supply and live again. Without this beneficent work of the fungi all the animals and plants that have died since the beginnings of life in the world, if they had not been eaten or burned, would still cumber the earth ; that is, the food of the world would be locked up in dead forms. Burning returns the nitro- gen to the air, — a most wasteful process, — while the decay of the dead bod- ies and waste matters of animals and plants caused by fungi holds this most precious of all foodstuffs in chemical combination as nitrates, ready again to be built up into the grains, seeds, fruits, and other food products of green plants (see Chapter IX). Thus, in burning wheat straw the farmer may rob his land of twenty-five pounds of nitrogen in combination, worth |3.75 per acre per year, and an acre of corn stover or cotton stalks may contain respec- tively $7.50 and $15.30 worth of nitrogen. Where it is cus- tomary to burn these materials is it any wonder that the wheat, cotton, and corn fields are worn out? NITRATES Fig. 90. Circulation of protein food materials in nature Nitrogenous food (protein) is the one essen- tial food of both animals and plants. The green plants build up this entire food sup- ply from the chemical elements by the energy of sunlight working through leaf green, or chlorophyll; nn represents free nitrogen from the air, drawn into combi- nation by symbiotic bacteria in the root tubercles of clovers, beans, etc. The non- nitrogenous foods — starches, sugars, gums, fats, and oils — are built iip along with the proteins and are finally oxidized to carbon dioxide and water, whether in the animal or plant body or by rotting or burning 188 CIVIC BIOLOGY Functional subdivisions, saprophytic, parasitic, and symbiotic fungi. Saprophytic fungi are those that hve upon the dead bodies or waste matters of animals or plants. Parasitic fungi attack living animals and plants and injure or kill them. They are the causative agents in the larger part of contagious or infectious animal and plant diseases. Symbiotic fungi live with other organisms, to the advantage of both. Bacteria in root tubercles of the legumes are familiar examples. While convenient, these lines of classification are not hard-and-fast, because it may be difficult, or even impossible, to tell whether an organism, or any part of it, is really dead or alive. The rough bark and the heartwood of a living tree are as dead as they ever will be,- so may be the hair or cuticle of a living animal, or the rind or pulp of a ripe fruit, or the food material of a seed or egg. Who can say whether the sap of a plant or the blood or milk of an animal is dead or alive ? So there are all degrees of liveness or deadness, and a usually beneficent saprophyte may attack a half-dead plant or animal, which we would call alive, but the fungus may know better. Accord- ingly we have hemiparasitic and hemisaprophytie,, or, so-called, facultative parasitic or saprophytic, fungi that attack the living or the dead according to degrees of vitality or variations of external conditions. Botanical position of fungi. All fungi are devoid of chloro- phyll, but not all plants that lack " leaf green " are fungi. Dodder and the Indian pipe are flowering plants that have adopted the parasitic habit, and with this degenerate life they have lost the mechanism and the power of making their own food. So we find from a study of their ways of growth and methods of reproduction that fungi have developed from the alga?. Flowering plants reproduce by seeds^ which are embryo plants provided with food for the start in life. The ferns, mosses, algae, and fungi reproduce by spores, which, compared with seeds, are almost inconceivably small. Many seeds are FUNGI 189 provided with hairs or wings to carry them in winds, and many float in the water in order to be widely scattered ; but the spores of the fungi are so light and small that they float invisible in either air or water, and so they far outstrip in dis- tribution the best devices of the higher plants. As a result, while the flora of seed plants is very different hi different countries, the molds and mushrooms, yeasts and bacteria, are more likely to be the same species the world over. Compare seeds and spores as to size and numbers pro- duced. For spores use the dust from a patch of mold and from a puffball, and try to see, feel, smell, and taste tliem. The finger tips may be black or green with millions of mold spores, but how much can we feel them? We can see the cloud of " smoke *' from a puffball, but as the spores scatter, can we see them in the air (unless in a ray of sunlight in a darkened room), and have we ever tasted them iii food ? Some people enjoy the tastes of certain molds and bacteria hi cheese, — Camembert, Roquefort, Stilton, Lim burger, — and they may be as wholesome as any other vegetable. How do the different kinds smell? How many spores may we be breathing in with every breatli in a musty room ? How does the number of seeds of a grain plant or weed compare with the spores produced by a puffball ? Size and power of growth. A baby grows to double its weight at birth in five months. A yeast plant or bacterium may double in size in twenty or thirty minutes. The fungus thus has from seven to ten thousand times the power of growth of the baby. Why this difference ? Food, again, is the basis of growth. To dissolve, digest, absorb, circulate to every part of a large body, assimilate (that is, build over the foreign matter into the particular pro- toplasm of the species) are slow and laborious processes. Solu- tion of food substances, especially the proteins (white of egg, gluten, casein, lean meat), is difficult, and absorption through 190 CIVIC BIOLOGY ^~" fi^ y p / z^ 2£ zf: / ^ — — / ■ h / i / L . , / / — / ___ ^ l— — , .^ _ zy the cell membranes is slow. The amount absorbed is pro- portional to the absorbing surface exposed to the solution. With these points in mind we may understand why the ac- tive mechanisms in living things are so minute, for only in this way are they able to present the largest possible sur- face for both the escape of waste matters and the absorption of food. The diagram on this page presents these relations in sim- ple form. A one-inch cube is seen to have six square inches of ab- sorbing surface, while in a ten-inch cube each cubic inch has only six tenths of one square inch of surface. The rate of absorption be- ing the same, the smaller cube could absorb ten times as fast as a similar bulk of the larger cube. So we see why the small- est organisms may be the most efficient in ab sorbing food and have the greatest power of growth. It is estimated that a bacterium jq^q^ of a milli- meter in diameter, which can double in size in twenty min- utes, given food and suitable conditions, might grow to a mass the size of the earth in about five days. A yeast plant, which is much larger but which can double in thirty minutes, might grow to a similar mass in about two weeks. How Fig. 91. Diagram to show relation of surface to bulk in large and small organisms The law is: Bulk increases as the cube, while surface for absorption increases only as the square. Since bulk so rapidly outstrips surface, this relation tends to limit the size of organisms, and suggests one of the fundamental reasons why minute organisms possess such phenom- ^enal powers of growth and reproduction FUNGI 191 long would it take a pair of elephants to multiply to a mass of the same weight ? Size. As we have seen, mere size counts for little. Bac- teria, the smallest plants known, are infinitely more powerful than sequoias or whales. Fungi range in size from the giant puff ball (the fruiting body of which may grow to three or even four feet in diameter) to microscopic bacteria, and some of these are quite possibly too minute to be visible under our best microscopes. In the fruiting portion of a large mushroom we see but a small part of the whole fungus. This consists, as we shall see later, of a feltwork of microscopic threads (the A ^^ B Fig. 92. Size of microscopic fungi Comparative size of : A, a, molds ; h and c, yeasts ; d, bacteria equally magnified ; B, e, minute particle of dust ; /, point of finest cambric needle ; g, bacteria under less magnification. After Conn feeding, or vegetative, portion), which permeate the soil, leaf mold, wood of a tree, or other substance in which the plant is growing, possibly for many feet in every direction. Yeasts {Saccharomycetes, the sugar fungi — saccharon, "sugar " ; myces, "fungus"). Yeasts are the "sweet tooth" fungi, and their work in nature is to break down sugars by the process known 2^'^ fermentation. The end products are alcohol, carbon dioxide, and various oils and flavors characteristic of different species of yeast. The process of fermentation is represented by the following simple chemical equation : 2C0„ Sugar 2C,H,0 , Alcohol Carbon Dioxide Size and color. Common yeast plants are spherical or ellip- soidal bodies about g^^Q of an inch in diameter; a cake of 192 CIVIC BIOLOGY compressed yeast contains approximately 10,000,000,000 of them. In order, once for all, to gain a notion of the minuteness of microorganisms, perform the following simple experiment : Sharpen tlie point of a teasing-needle to a tine knife blade ; take a bit of moist compressed yeast, the size of a large pinhead, on a piece of clean, polished glass (a microscope slide) and cut the lump in halves. Throw away one half and repeat the operation and continue as long as you can see to divide the particle. At the last division carefully plant one half in a vial half full of filtered, boiled molasses and water (a table- spoonful of molasses in half a pint of potato water makes a good cul- ture fluid), to watch it grow from day to day. Then, with the point of a clean needle, on a perfectly clean part of the glass, cover the other half with a minute droplet of water. Cover with a per- fectly clean cover glass ajid try to count the tor- ulaB (yeast plants) in the speck that you can just see with the naked eve. Fig. 93. Yeast plants, highly magnified, show ing successive stages of growth by budding After Conn In color most of the common yeasts, when seen in mass, are whit- ish or slightly yellowish gray, the color of a fresh yeast cake, but a few species are pink, red, or black. Distribution. Yeasts are everywhere ; so the question is not. Where shall we go to find them, but. Where go to escape them ? We eat them by billions, baked, in our daily bread ; Ave drink them by millions, alive, in our cider, beer, or wine ; we breathe them in, alive, with every breath, and drhdv them, alive or dead, according as the Avater is raw or boiled, with every drink of water we take ; they are all over us all the time, in our hair, on our skins, in all our clothes, and we cannot possibly l)eat them out, brush them off, or even wash them away — the harmless, useful, patient, persistent, omni- present little sugar-hunting yeast plants. We might suck EUNGI 193 most of them out of our carpets aud homes with a vacuum cleaner, but this would not be worth our while if it were not for the fact that they are associated in the dust with less reputable bacteria. There is just one point that we should learn in a way Ave can never forget. The skins of fruits, of course, are covered Fig. 94. Experimeiit.s in growing yeast. 1, yeast planted in molasses 1 part, water 5 imrts, kept at room temperature; 2, same, kept in dark; 3, planted in filtered, boiled, or distilled water; 4, same as 1, not planted : T), same as 1, kept in cracked ice with yeasts and with spores of molds. This fact is related to one of the large industries of the world — the picking, hand- ling, and marketing of fruits. Experiment 1. Have the class collect a number of the fruits avail- able at the season. Scrape the surface lightly with a sharp, clean scalpel point or knife-needle (or wash with a fine brush into a drop of water on 194 CIVIC BIOLOGY a slide). Mount scrapings in a small droplet of water and examine under a microscope. Be particular to scrape especially in the little crack around the stem. Can you see from results why stems should not be pulled out in picking fruit ? Experiment 2. Pull out the stems and make slight punctures and scratches through the skins of a number of apples or pears, set them aside with an equal number of perfectly sound fruits, and examine from time to time for signs of decay. Experiment 3. Plant scrapings from the skins of the various fruits in vials of dilute fruit juice (filtered cider, the juice from canned fruit, diluted with half water if too sweet), plug with cotton, and examine later for growth of yeasts and molds. If microscopes are not at hand. Experiments 2 and 3 can be done perfectly well without them. What do these experiments mean with reference to honest hand picking and packing of fruits ? If one decayed fruit wets or touches another, what is likely to happen? Contagion? Uses. In making bread we use the carbonic acid which the yeast plants give off to form bubbles in the dough. These bubbles are hardened in baking, the alcohol is driven off, and the bread remains light. In making alcohol we use the sugar of fruits or the starch of potatoes, barley, corn, rye, which has been changed to sugars by digestive ferments; then either the wild yeasts that were on the fruits or the pure-culture yeasts that we add to the fruit juice mash or wort ferment the sugars, and the alcohol may be distilled off by heat. If the yeast fermentation has been too slow, or if the mate- rial is allowed to stand after alcoholic fermentation is complete, other microorganisms, with which yeast is always associated, begin to turn the alcohol into acetic acid, and we have sour bread, sour beer, and vinegar. This process may be roughly represented by the equation Alcohol Oxygen Acetic acid Water Then if vinegar is exposed to the air, another organism may change the acetic acid further into carbonic acid and water, and the decomposition of the starch or sugar is complete. FUNGI 195 Experiment. To a quart of warm potato water, not filtered, add a half pint of molasses and a yeast cake, previously mixed to a smooth cream in a gill of fresh milk. Keep in a dark place at between 75° and 90° F., and observe from time to time. When bubbles are rising rapidly, conduct the gas into a vial of lime water, as shown in Fig. 95, noting that the same change takes place that occurs when we expire into limewater : CaO + CO2 = CaCOg Liine Carbon Chalk or dioxide limestone Test the liquid by odor and especially by taste. As soon as fermentation is complete (that is, when the sweet taste has dis- appeared), pour out half a pint into a flat dish and set in a warm place, protected from dust, to study the formation of vinegar. With the remainder attach the flask to a small still, heat care- fully, and test the first gill for alcohol by taste, smell, and by burning. In doing this experiment dif- ferent members of the class, or different class groups, may use different materials — fruit juices, potato, corn or rye mashes, malt decoction — and thus add to the interest. Pure cultures. Before reading the next experiment try hard to think how you would make a pure culture of a plant 3 o'o^o" ^^ ^^ ^^^^ ^^ "g^oioo" ^^ ^^ ^^^^ ^^ diameter. Let each member of the class write out his method and then compare ^is result with those of the rest of the class. This is a test and measure of power to think, imagine, and reason. When Louis Pasteur first thought this out, he marked the greatest epoch in control of disease that history records. Pasteur did this first with the yeast plant in 1856. Up to this time Fig. 95. Testing the gas from yeast, fermentation with limewater 196 CIVIC BIOLOGY fermentation was supposed to be a purely chemical process, and accordingly brewers and vintners had employed chemists to try to relieve them from the great losses caused by diseases of wine and beer. We now know that these were caused by wild yeasts and otlier microorganisms, and the problem is a logically simple one of weeding them out of the cultures. The first requisite is to isolate and study the different organ- isms involved, in pure cultures, and this is equally true of any germ disease of plants, animals, or men. Experiment 1. First necessary step: Get the yeast plants single; that is, make a uniform suspension in water. To do this make a dilute, well-rubbed-up suspension in a slender test tube or straight vial, and force down through this a tight, hard plug of sterilized ab- sorbent cotton. The liquid above the cotton will be pretty sure to contain noth- ing but single yeast plants. Experiment 2. Second step : Get the single plants far enough apart so that we can work with them ; that is, dilute the suspension. Add a drop to, say, one quart of boiled, filtered water, and shake thoroughly. (If too many plants are still present, we may have Uy repeat the dilution.) Experiment 8. Third step: Plant a drop or a few drops (according to the dilution) in some medium solid enough to keep them from flow- ing together and getting mixed up, and clear enough so that we can see them after each one has grown sufficiently to forui a visible colony. Starch jelly made with sweetened water (or potato water filtered) makes a good mediuui foe yeasts and molds. Stir the drop of sus- pension thoroughly into a tablespoonful of the jelly as soon as it is cool enough not to injure the yeast (when it feels neither cool nor warm to the hand), and pour in a thin layer into a Petri dish (or on a clean piece of glass which can be covered securely from the dust). Keep in a warm place away from the light, and in a day or two whitish specks begin to appear, if the work has been carefully done, scattered Fig. 96. A lifter, cut from tin, or, better, from thin sheet aluminium It is sterilized by holding the end in a flame for an instant, giving it only time to cool befoi'c using, a, sheet of metal indicating how the lift- ers are cut. (One half natural size) FUNGI 197 evenly through the mass. If a speck is spherical and clearly distinct from all others, we may pick it out with a sterilized lifter and be reasonably sure that we have yeast plants all descended from a single parent plant — that is, a pure culture. Diseases caused by yeasts. Quite naturally one species of yeast causes blight of sorghum, and another, a disease of the crocus, and one or two others attack animals and man. Molds and mildews. These are the most troublesome fungi of the household. They take everything in the way of food or clothing, carpets, linen, and even books, that they can get their spores on, if conditions, especially of moisture, .favor their growth; and since they always can get their spores on everything that tlie air touches, it behooves the home-keeper to see to it that nothing of value is left where dampness, air stagnation, and darkness may permit growth of these little robber plants. Conn's statement is : " If the air of a room becomes damp or ' close,' as we say, it is almost certain that molds will begin to grow upon any organic substance." While in common household parlance molds and mildews are sup- posed to be distinct, the microscope reveals them as identical, the only difference being that they grow less luxuriantly on leather, cloth, and paper than they do on richer and moister foods. Botanical position and structure. The word "mold" is merely a popular designation for a variety of different kinds of plants. The term has no botanical standing, but is so firmly fixed in common usage that we cannot improve upon it to designate the somewhat similar felt-like growth that is likely to cover everything damp.* This growth is tech- nically known as the mycelium of a fungus, and when we examine it we find the key to understanding the growth and structure of all the higher fungi, molds, and mushrooms — that is, those above the bacteria and yeasts, and some of these form similar mycelia. The single element is a microscopic 198 CIVIC BIOLOGY thread, the hypha, which in some fungi is tubular and in others is septate, that is, composed of cells end-to-end. Hyphee branch continually and seek the cracks and minutest pores, and so are able to burrow and digest their way into all sorts of apparently solid substances. The hyphse are functionally of two kinds : first, the threads that burrow and feed in or on Fig. 97. Two common molds in different stages of growth A, B, C, a common blue mold, Penlcillium ; A, spores germinating; B, as seen growing in vial of liquid ; C, aerial (or fruiting) hyphte more highly magnified ; D, E, F, similar stages in the growth of a black mold, Rhizopus the food material — the vegetative hyph?e ; and, second, the fruiting hyphse, which grow out of the mass into the air (or water in case of the water molds) to form the various kmds of spore-bearing organs. These ideas are fundamental to control of fungi, and we should be sure that they are entkely clear in working out the following experiments. As we aim to destroy weeds before they go to seed, so we must adopt meth- ods to prevent our fungus enemies from ripening their spores. FUNGI 199 Observations and experiments. 1. For at least one hour in preparation of this lesson have each member of the class hunt over his home premises and collect specimens of everything he can find that appears to be moldy. Compare these, to try to see how many different molds we have. The mycelium of nearly all molds and mushrooms is white, but the spores and sporing organs may be any color — white, red, green, gray, brown, or black. Note particularly the kinds of places in which molds are found growing best, with especial reference to damp- ness, lack of light and direct sunshine, and lack of ventilation. 2. Select tyi3ical specimens and arrange in jelly tumblers (or even in straight-necked vials) for further study. Keep covered when not in use. 3. Make a series of mold gardens in small vials, trying to have as pure cultures as possible. Use all sorts of materials — foods and even linen and cotton cloth. Plant spores from No. 2 by touching a patch of mold with the point of a needle and then touching it to a single point in the material in the vial. Watch it grow from day to day, noting particularly how long it takes to begin to produce spores. To insure dampness the vials should be covered or corked tightly (heavy tinfoil pressed over the mouth of the vial makes a convenient cover), and should contain a little water. The material may be held out of the water on a bit of glass.' Stand some of the vials in bright sunlight, and keep the rest in the dark, noting differences in growth. Keep some on ice (cold storage) and compare. Keep some protected from dust in a dry air, not covered tightly, and note influence of dryness on growth of molds. In order to see the growth clearly, make a series of mold gardens ^ in a perfectly transparent liquid medium. Fruit juice, diluted with one half water, filtered, serves the purpose well. Plant spores from the different molds on the surface, study from day to day, make careful drawings, and note especially the time required for spores to begin to form. 4. Sketch a plan by which you would keep a home as free as possible from molds. 1 Hodge, "Nature Study and Life," p. 4-57 ff., describes and figures mold gardens. CHAPTER XIX FUNGI CONTINUED : MUSHROOMS, POISONOUS AND EDIBLE To know several different kinds of edible mushrooms, which occur in greater or less quantity through the different seasons, would enable those in- terested in these plants to provide a palatable food at the expense only of the time required to collect tliem. To know several of the poisonous ones also is important, in order certainly to avoid them. — Atkinson, '' Mushrooms," p. iv General. Persistent search extending through a series of years in any favorable locality would reveal the presence of about 1000 species of these our largest and most conspicuous fungi. In one season one might expect to find from 200 to 400 species. Of the entire number, according to Mcllvane, nine species (all amanitas) are deadly poisonous, about a dozen contain minor poisons, and are rated as suspicious or dangerous, 735 are edible, while the rest have either not been tested or, on account of woodiness, disagreeable taste, small size, or extreme rareness, are of interest only to the specialist. Form and structure. Mushrooms, like other fungi, are active in causing decay, chiefly in waste matters of plants and ani- mals, but a number attack the roots and wood of trees, and, naturally timber and wooden structures. From our knowledge of the molds it is an easy step to the life history of a mushroom. Both organisms begin as spores ; in both, these sprout and grow to form a mass of food-absorb- ing mycelium. In mushrooms this may extend many feet in the soil, in leaf mold, or in the wood of a tree. In both, some of the mycelial threads finally grow out of the food substance and complete the life cycle by producing the spores with which 200 FUXGI 201 we started. The conspicuous part of a mushroom is 'thus a small fraction of the entire plant — the spore-bearing organ, or sporophore. Combme the collecting of mushrooms with the field work with birds, insects, and trees in the early fall. In fact, this is the most favorable part of the school year for all forms except the morels, whose season is May or June. Preserve Fig. 98. Growth stages of a mushroom A, mycelium with forming buttons, drawn from Agaricus canipestrls. The other figures are from Amanita phalloides (the deadly amanita) and show : B, a button bursting the volva (or sac) ; C, the same in longitudinal section ; and D, a mush- I'oom showing a, the pileus (or cap), 6, the velum (or veil), which has torn from the margin of the cap and remains as a ring around the stem, and c, the remains of the volva, which forms a cup the mushrooms collected for winter study by drying ; even many of the softer ones may be preserved in this way if they are dried^in a current of hot air. Amanitas. Before collecting mushrooms, fix clearly in mind the characters of the deadly genus Ammiita. Other varieties of fungi may interfere with digestion, but to the Amanitas all deaths from toadstool poisoning are traceable. Its subtile alkaloid is absorbed by the system, and in most cases lies unsuspected 20-2 CIVIC BIOLOGY for from six to twelve hours, then its iron grip holds to the death. For centuries it has defied all remedies. — McIlvane, p. 5 The amaiiitas are the most conspicuous, beautiful, and, too often, the most abundant mushrooms to be found in the woods from frost to frost. Of the twenty-eight species nine are deadly, ten are doubtful, and nine are considered edible. The three characters which infallibly mark an amanita are white spores, a ring, and a volva, or cup. In order to understand these terms and others that we need to know, study an amanita as a type. Fig. 98 shows all the constituent parts and all the characteristic stages of growth of Amayiita phalloides. The parts in order of growth and formation are Mycelium : extremely fine white threads, uniting here and thereto form larger strands — the nutritive, or vegetative, part of the fungus. Buttons : white knots or balls in the mycelium, the beginnings of spore-forming bodies (mushrooms). One button cut lengthwise shows the parts, which will be more clearly differentiated later on. Note especially that the mushroom proper at this stage is completely enveloped in a sac. Not all mushrooms have this sac. Sporophore, consisting of 1. Stem: the part which springs directly out of the mycelium and supports the pileus. 2. Pileus^ or Cap : the umbrella-shaped part which carries, on its under surface, radiating, leaf-like structures — the gills. 3. Gills : the organs from the surfaces of which the spores are set free. The shape that the spore-forming surface assumes is a prime character in classification. It is produced into gills in the Affaricacece, into spines in the Hydnacece, into tubes in the Boleti, and into fine pores in the Polypori. Spores ; Place a cap from which the stem has been removed, gills down, on a piece of white or black paper, and cover tightly with a tumbler or bell jar. Leave for an hour or so, and examine the spore print and, if a microscope is available, the spores. VoLVA, or Sac : the membranous sac which may envelop the entire sporophore in the button stage ; also applied to the portion which, after rupture, remains as the cup at the base of the stem. FUNGI 203 Warts : irregular flecks, or patches, on the surface of the cap, formed if the volva ruptures about the equator and the upper portion is carried up and remains adherent to the growing pileus (not the case with Amanita phalloides). Velum, or Veil : a membrane which, in some forms, attaches the margin of the pileus to the stem. When, in growing, the cap tears away from the velum around its margin, the velum re- mains attached to the stem as the annulus, or ring. The presence of the three characters, white spores, ring, and cup (which may be reduced to a scaly, bulbous base to the stem), mark the specimen as an amanita. In collecting, why should we be sure to have the base of the stem complete? Why should we never mix buttons with edible mushrooms ? Classification. Sort the mushrooms collected, using the outline given below. If you place the dried specimens in a jar packed with wet paper the day before beginning the work, many of them will absorb moisture and become approximately like fresh specimens : 1. All forms with gills underneath the pileus may or may not have stems — Agaricacece. 2. Hedgehog mushrooms : forms whose spore-forming surface is pro- duced into spines which hang downward. They may be umbrella-shaped or irregularly tuberculate or branched — Hydnacece. 3. Mushrooms with a honeycomb structure of tubes in place of gills ; soft and with the tubes readily separable from the cap — BoletL 4. Fungi with fine pores underneath the pileus. Many species become corky or woody, the bracket fungi of the woods — Polypori. 5. Coral mushrooms : may be simple, erect clubs or large, branching masses, the branches being erect. The spores are produced over most of the exposed surface — Clavariacece. 6. The morels and cup fungi. Some of these have stem and cap, but produce the^^ores in pits or irregular depressions on the outer surface of the conical or cylindrical cap. Other forms are cup-shaped or saucer- shaped — Discomycetes. 7. Puffballs and earthstars : mushrooms in which the spores are pro- duced within a closed cavity, which may open by an apical pore or by the irregular breaking of the wall (peridium) — LycoperdacecE. 204 CIVIC BIOLOOY 8. Stinkhorns, mushrooms which, once smelled, can never be mistaken for anything else or forgotten. The immature plants, known appropri- ately as witches'-eggs, resemble puffballs externally ; but as one matures, out shoots a long, hollow stem bearing pendent from the tip a small j)ileus, and this carries the spores in reticulations of its outer surface — Phalloidect. 9. Trembling mushrooms : soft, gelatinous fungi (witches'-butter) in. color varying from white to orange, red, or brown, generally found grow- ing on wood or parasitic on other fungi — Tremellacefv.. The first purpose of these lessons should be to learn to recognize the deadly genus Amanita. Then let each student acquaint himself with as many as possible of the abundant edible mushrooms. An excellent plan is to have the class unite in making a neat card catalogue of the most abundant and valuable mushrooms found growing in the locality — this catalogue to be left in the laboratory as part of its biological equipment during the year. A sample card might read about as follows : ORDER: AGAlilCACE^ Genus : Lactarhis Spkciks : (leliciosus Spohks : White Delicious Milky Mushroom Edible, excellent (first taste a little acrid) Space for Color Picture 3-10 cm. high ; 5-13 cm. broad ; funnel-shaped. Color : orange, in concentric darker and lighter zones around cap ; becomes lighter, often green^ ish, with Bjge. Gills : decurrent, saffron yellow. Milk at first reddish orange, quickly turning to dull greenish — char- acteristic of every part of plant when bruised. Odor: aromatic. Taste : delicious. Habitat : damp coniferous woods. Season : July to October. Notes : Have found it abundant since our first field work — Sejv tember 10 up to October 23. FUNGI 205 Table of Gkneka of Agaricace.e (Gill-bearing Mushrooms)^ I'lLKfS DISTINCT FROM FLESHY STEM SrouES Leucospob.ic (White) RnoDospoRx (Pink) OciinospoRjF. (Yellow-brown) Porpiiyrosporm: (Purple-brown) ME[.AKO!IPOR.f: (Black) Ring and volva Amanita^ Volva, no ring Anianitopsis* Volraria^ Acetabulana Chitonia Ring, no volva Lepiota* Agaricua * CoprinuH * No ring Piute us Bolbitius Pilosace PI LEI S CONTINUOUS WITH FLESHY .STEM King Armillaria * Pholiota* C'ortiuarius* Stropharia^ Gomphidius Sinuate gills Tricholorna * Entnloma^ Hebeloma ' Hypholoma* Panseolus 3 LactaHus^ (milky) liussula* (brittle) Inocybe Anellaria Gills often decnr- rent Cantharellus * Xerotus Nyctalis Clitoj/ilus* Flammula Paxillus* Growing on wood. Stem usually ec- centric, lateral , or wanting Lcnzites Lentinus ' Pleurotus * (fleshy) Panus (leathery) Trogia (gills crisped) SchizQphyllmii^ Claudopns Crepidotus PILEUS DISTINCT KKOM CARTILAGINOUS STEM Margin of pileus inroUed in young plant Collybia^ Leptonia Xaucoria Psilocybe* Marasmius* Heliomyces Margin of pileus straight in young plant Mycena Hiatula Nnlanea Pluteolus Galeru Psathyra Psalhyrella Gills decurrent, pileus usually um- bilicate Omphalia \ Krcilia Tubaria Deconica Montagnites 1 Arranged by Theodate L. Smith, Ph. I). ^ Contains deadly poison species. No species of Amanita should be eaten without Mentijication by an expert. * Contains suspicious species or tliose having minor poisons. * Contains edible species and none known to be poisonous except those given below : Lepiota morganl has green spores ; it is one of the finest edihles, but makes ill about one person in six. Russula emetica causes nausea in some people, but is harmless for others. Tricholorna sulphure\is smells like illuminating gas and is reputed poisonous. Hygrophorus conictis is reputed poisonous. Clitocyhe illudens smells and tastes like soap and is reputed poisonous. 206 CIVIC BIOLOGY The table on the precedmg page will enable the beginner to place any agaric in its proper genus, and indicates the genera that contain edible species. The other families, espe- cially the puffballs, morels, boleti, coral and hedgehog mush- rooms, also contain many edible species. In fact, almost all of them that are agreeable to the taste are perfectly safe if taken in prime condition. All the soft-skinned puffballs, if perfectly white to the center, are free from suspicion, as are all the morels, all the hydnums, and all but one of the coral mush- rooms — Clavaria dichofoma, a rare, pure-white form, in which all the branches fork regularly. Among the boleti the group luridi, characterized by red mouths of the tubes, contain species that are rated as poisonous. Raising mushrooms is a growing industry. Can members of the class visit local mushroom cellars and report on methods employed ? If none are grown locally, cannot a committee of the class try the experiment as an industrial project ? Several of the state experiment stations and the United States agri- cultural department publish bulletins that will give the neces- sary information. As a people we are permitting a considerable food supply to go to waste. As we study the matter, can we estimate the amount and value of the mushrooms that grow annually on our home premises and in our gardens, lawns, woods, and meadows? What might these figures be for our township, county, and state? CHAPTER XX FUNGOUS AND BACTERIAL DISEASES OF PLANTS Estimates which have been placed upon the damage caused by preva- lent plant diseases during a single season amount frequently to a very con- siderable per cent of the total value of the crops. In the United States alone the destruction wrought by fungous diseases is sometimes not far from half a billion dollars. — Duggar, "Fungous Diseases of Plants,^' pp. 7-8 Civic aspects. Line fences of farm or city lots offer no barriers to clouds of fungus spores in the air. So the spores Fig. 99. Mummied plums destroyed by brown rot (Sderotinia fructigena). At left, tumor on branch, caused by black knot {Plowrigfdia morbosa) of rusts and smuts of grains may sweep over the fields from Texas to Manitoba, or they may live unseen on seeds and thus be distributed the world over. The spores or myce- lium, as is the case with smut of corn and onion, scab and rot of potato, and clubroot of cabbage and turnip, may re- main alive in the soil from year to year. Such fungi can be controlled only by strict rotation of crops. We thus be- gin to realize the size of our problem in its world-wide 207 208 CIVIC BIOLOGY scope, and may be prepared to conclude that its final solution must depend on intelligent, world-wide cooperation. Irish famine. It was the great famine in Ireland in 1845- 1847 that opened the eyes of the whole world to what a fungous disease of a plant might mean to a people, and the awakening that followed marks the beginning of modern plant pathology. * The case illustrates, too, the apparent suddenness of the attack, and also the total destruction of the crop the second year if rotation is not resorted to. Ireland had become densely populated, a large part of the people were almost wholly dependent on the potato for food, and the fungus that caused the famine was the late blight, or rot, of the potato — PhytopTithora irifestans. The harvest of 1845 [»roiuised to be the richest gathered for many years. Suddenly, in one short month, in one week it might be said, the withering breath of a simoom seemed to sweep the land, blasting all in its path. I myself saw whole tracts of potato growth changed in one night from smiling luxuriance to a shriveled and blackened waste. A shout of alarm arose. But the buoyant nature of the Celtic peasant did not yet give way. The crop was so profuse that it was expected the healthy portion w^ould reach an average result. Winter revealed the alarming fact that the tubers had rotted in pit and storehouse. Nevertheless the farmers, like hapless men who double their stakes to recover losses, made only more strenuous exertions to till a larger breadth in 1846. Although already feeling the pinch of sore distress, if not actual famine, they w^orked as if for dear life ; they begged and borrowed on any terms the means whereby to crop the land once more. The pawn offices were choked with the humble finery that had shone at the village dance or the christening feast ; the banks and money- lenders were besieged with apjwals for credit. Meals were stinted, backs were bared. Anything, anything to tide over the interval to the harvest of "Forty-six." O God, it is a dreadful thought that all this effort was but more ' surely leading them to ruin ! It was this harvest of Forty-six that sealed their doom. Not partially but completely, utterly, hopelessly, it perished. As in the previous year, all promised brightly up to the close of July. Then, suddenly, in a night, whole areas were blighted; and this time, alas! no portion I FUNGOUS AND BACTEKIAL DISEASES 209 of the crop escaped. A cry of agony and despair went up all over the land. The last desperate stake for life had been played and all was lost. The doomed people realized but too well what was before them. Last year's premonitory sufferings had exhausted them and now? — they must die. We raised a public subscription, and employed two men with horse and cart to go around each day and gather up the dead. One by one they were taken to a great pit at Ardnabrahair Abbey and dropped through the hinged bottom of a trap-coffin into a common grave below. In the remoter rural districts even this rude sepulcher was impossible. In the field and by the ditchside the victims lay as they fell, till some charitable hand was found to cover them with the adjacent soil. — Lord E. Fitzmaurice and J. R. Thursfif.ld, in Lamed's "History for Ready Reference," Ireland, 1845-1847 Here we have our problem in the large and m concrete form. An enemy has killed by starvation nearly a million people.^ What is this enemy ? Who saw it come or go ? How does it operate ? Why did it do this ? How can we prevent future calamities of this kind ? The world had to await alleviation of fears and superstitions, discoveries in many fields, and growtli of the science of botany before many of these questions could be answered. Nothing can surpass in human value and interest, however, the quality of mind that works out solutions for such problems. In the light of the Irish famine, what may be the human value of such discoveries ? I'o get an insight into growth of knowledge in this field, call for at least three volunteers. Let number one read up the story of this famine further and report to the class. This is to develop a feeling for the need and motive for such study. Let number two look up and report -on the story of discoveries leading up to determining' and naming the fungus and devising methods for its control.^ Number 1 Returns to date (September 15, 1915) give total losses, killed, wounded, and missing in the British army, after more than a year of the great war, at less than 400,000. 2 See work of Dr. Berkeley (1846), Louis Pasteur (1856), especially De Bary (1861 and later), and Millardet, discoverer of Bordeaux mixture (1883). 210 CIVIC BIOLOGY three may collect specimens showing all stages of infestation of leaves and tubers for actual demonstration, make pictures of the fungus and diagrams showing how it attacks the potato plant, and finally give the best methods for its control. Infection. The process of infection is as simple as that of planting seeds in a garden plot and raising the particular kind of flower or vegetable or of inoculating mold spores in any sort of food cultures. The spores of the parasite germi- nate in contact with their host plant, and the hyphse enter through wounds or stomata or actually eat their way through the cells of the surface. In order to develop perfectly clear ideas, perform all sorts of in- oculation experiments with fungi that happen to be available. Let members of the class use different kinds and demonstrate methods and results. Use any of the following, or others of local importance. Inoculate by touching point of pin to spores and pricking surface : A potato tuber or leaf with spores of blight or scab ; Seedlings of corn, or other grains, with smuts or rusts ; Lettuce plants with spores of "drop" (Sclerotinia Ubertiand) if locally important ; An apple with spores of bitter rot ; A plum, peach, or cherry with spores of brown rot (Sderotima fructigend), always at hand everywhere ; Bean seedlings with germs of bacterial blight (Pseudomonaa phaseoli) or spores of pod spot or anthracnose (ColletotricJium lindemuthianum^. In these days of quack nostrums, illogical thinking, and even hysterical denial of cause and effect in matters of disease, these lessons wdth plants, which are not subject to fears and perverted mentality, may help to keep us sane. Wound infection of trees. A search through the orchard or wood lot is all too likely to show trees with mushrooms of different kinds — polypori, hydnums, oyster and honey mushrooms — growing upon trunks or roots. Inspection seldom fails to reveal the wound in the bark through which the fungus entered the wood. It is probable that these rUKGOUS AND BACTEKIAL DISEASES 211 parasites destroy more timber annually than do forest fires. The visible portions, the sporophores, of these tree-destroying fungi are pushed out at certain seasons, or during certain weather conditions, and pour clouds of spores into the air to infect surrounding trees. These disease breeders should be the first to be made into firewood in annual cutting from the wood lot. The sporophores should also be destroyed as soon as they appear. By a little intelligent cooperation a commu- nity could bring these pests under control, and however valuable the trees may be in themselves, the study will be worth while as an example of spread and preven- tion of disease. Koot rot of fruit trees is a matter that will call for special attention in certain sections. Two con- spicuous mushrooms, Cli- tocyhe parasitica and the common honey mush- room (Armillaria mellea), show strong parasitic tendencies when .brought into contact with the roots or crowns of apple, peach, or cherry trees. In clearing land for orchards it is advisable to remove all stumps and roots that are likely to harbor these fungi. Invite the local forester or tree surgeon to discuss these problems with the class. Learn from him the best treatment for tree wounds. (Wounds of any size made in pruning should be sealed with paint or gas tar.) As laboratory work let the class, in convenient groups, make some experiments in tree surgery where most needed about homes, school yard, or streets. Civic types for study. Duggar describes, or mentions, in his book " Fungous Diseases of Plants," 238 fungi that attack the common plants and trees of forest, orchard, garden, and field. He also gives a most useful Host Index Fig. 100. Apple inoculated, at pin, with spores of brown rot from mummied plum. Control apple As instructive as a case of smallpox 212 CIVIC BIOLOGY (the host is the organism that supports a parasite), iii which he lists 174 plants, with the fungi that attack each. From this we see that everything we try to raise has its fungus enemies : alfalfa has anthracnose, leaf spot, root gall, European root disease, and root rot ; the apple has 24, among them anthracnose, or bitter rot, fire blight, crown gall, rust, and scab ; beans have 7 ; corn, 6 ; cotton, 9 ; the grape, 9 ; potato, 6 ; tomato, 8 ; wheat, 7 ; violet, 6 ; pine, 6 ; oak, 7; and so on through the list. The following bacte- rial diseases are common : Pear and apple blight. Leaves turn brown as though burned with fire. The germ was supposed to be carried by bees to the blossoms, but it is probably inoculated by aphides. Limbs that show symptoms of the disease should be cut below traces of the blight and burned. Wilt disease. This disease affects tomatoes, cucumbers, melons, cotton, and Irish potatoes, and causes the plants to wilt rapidly and die. Black rot of cabbage. The germ attacks cabbage, turnips, rutabaga, and cauliflower. Leaves turn black and the plant dies. This disease is common in America and Europe. Try, at least, to make a preliminary survey, and then choose for intensive study the local types that are most im- portant, and especially those that require general knowledge and united effort of the com muni tv to control — the civic Fig. 101. Loose smut of oats {Ustilago avencB) and normal heads FUNGOUS AND BACTERIAL DISEASES 213 types. It may be possible for each pupil to make a table giving for each fruit, vegetable, and farm crop the loss caused by fungi — that is, to answer the question, What part of the half -billion-dollar tax does my home pay? A suggestion for such a table is given below. Losses Caused by Fungi on a Gkain Farm of 320 Acres ^ ! Number j OF Acres Yield in Bushels Per Cent Injured Price Price of Smutted Total Loss Wheat . . Oats . . Corn . . Potatoes . Orchard . 280 40 . 1 10 • ! ^ 4 47 30 75 48 17 10 7 75 11.30 .40 .75 .50 #.85 $8,843.80 140.80 42.00 144.00 26.50 2 Total . • ! $9,197.10 National and world problem. The general situation is aptly expressed by the complamt heard on every hand: The world is not fit to live in any more, and it 's getting worse and worse every year. We never used to hear about all these new-fangled diseases all the time, and everything didn't use to rot and smut and blight when I was a girl back on the old farm. This is literally true and for several good reasons. People (lid not then know what was eating them out of house and 1 Wheat is supposed to be affected with stinking smut, which Duggar says sometimes takes "from one half to two thirds of a crop" of some sections. Loose smut, corn smut, and early blight are the fungi supposed to have attacked the oats, corn, and potatoes respectively. Estimates are not ex- cessive. The percentages for the wheat, oats, and corn are figured by count- ing 100 stalks taken at random in ten different parts of the field. (Save several of these bundles of wheat or oats for demonstration in the labo- ratory and at neighborhood meetings.) The potatoes are estimated from usual results in case of sprayed and unsprayed field plots. The cost of treating the wheat and oats with formalin would have been a trifling insurance against the loss incurred. ^ Cost of three sprayings and one pruning for blight, bitter rot, etc. 214 CIVIC BIOLOGY home. They called it Providence and did not talk about it. Again, modern commerce and travel are rapidly mixing Fig. 102. Tree (on the right) infected with peach yellows Peach yellows is a contagious disease, exterminative of the peach in northeastern United States, that has baffled all attempts to discover its cause. The tree shown on the right is in the last stages of the disease ; the one on the left is healthy the bacteria, fungi, and insects of all the world, and these are the forces that have often determined both the floras and the faunas of continents. More American Indians have been FUNGOUS AND BACTERIAL DISEASES 215 killed by European bacteria than by bullets. Measles struck the Fiji Islands like a deadly pestilence. So we inspect and quarantine against the importation of such germs as those of bubonic plague, Asiatic cholera, and foot-and-mouth disease, but they slip by in spite of all precautions. The canker, or chestnut-bark disease, appeared about ten years ago, coming probably from Japan. Working as it does, between wood and bark, it cannot be reached by sprays, and there are not men enough available to prune and burn the diseased trees. It is said to have destroyed over $30,000,000 worth of chestnut trees, and predictions appear to be well founded that it may not leave a single one alive in eastern North America. 1 A third reason is that we are planting large areas to the same crop, with field against field. This is like piling up kindling for a fire, when a disease gets a start. Control measures. Methods are improving continually, and the only safe course to pursue in this field is to correspond with our nearest experiment station and secure their latest spray calendars, take the monthly list of publications, and keep abreast of discoveries. The underlying principles, how- ever, should be generally understood. 1. Be sure to plant healthy, uninfected, free-from-disease seeds, tubers, bulbs, or nursery stock. This refers to germs of disease inside the seed, tuber, or stock, and applies, of course, to buds and scions. Peach yellows, while the germ has not been discovered, is known to be transmitted from diseased trees in seeds, buds, or scions. Wilt dis- ease of sweet corn, or Stewart's disease, sometimes destructive to from 80 per cent to 100 per cent of the crop, is transmitted on, and prob- ably in, the seed. Seed should not be saved, or distributed to uncon- taminated land, from infected fields. The same is true of anthracnose of beans and cotton ; bean blight ; bacterial blight, or wilt, of potato ; 1 The species might be saved to the continent if nuts from sections as yet uninfected could be sent to suitable places on the Pacific coast and planted and reared beyond probable reach of infection. The United States Bureau of Forestry would probably be glad to supply safe seeds to biology classes that would agree to follow out directions for planting and culture. 216 CIVIC BIOLOGY late blight, or rot, and dry rot, or stem blight, of potato ; and crown gall of grapes, berry bushes, and fruit trees. 80, too, pear and apple blight have often been scattered broadcast from nurseries because disinfec- tion of pruning tools was neglected. In general, disiease shows u}) clearly in the nursery or field, W'hile it would require bacteriological and microscopic methods to find the germs within the seeds or stocks. Go out and hunt over local nurseries or seed farms. Ask experts from them to come in and demonstrate and discuss their methods. All W'ho Fig. 103. Corn smut {Ustilago zece) l)ropose to distribute these important supplies to the public ought to know their business by this time. The best firms employ trained ex- perts to see to it that stock is free from disease, and then they may send it to branch farms, far away from any possible contamination, to have it propagated for the market. 2. If spores are alive on the seeds or tubers, ready to attack the embryo plant when it germinates, kill them before planting. Scab of potatoes and smuts of grains are examples. Soak seed potatoes for two hours in formalin solution (1 ounce to 2 gallons of water) or in mercuric chloride (corrosive sublimate) solution (1 ounce to 8 gallons of w^ater). External spores of the smuts on wheat, oats, and barley are killed by soaking for from ten to twenty minutes in formalin solution (1 pint to 30 gallons of water) or by warming up the seed in water at 110°-120° and then holding it for ten minutes in water at 132°-133° F. FUNGOUS AND BACTEKIAL DISEASES 217 'i. If living spores arc coiitiimally sifting down from the air, we must keep the surface of leaf or fruit covered with something that will kill them as they germinate. If we wait till they get in, the crop will be ruined. Various Bordeaux solutions and lime-sulfur washes are effective for this purpose, and, naturally, while leaves are unfolding rapidly or fruit is growing, we must spray every few days. 4. If the spores are alive in the soil, there is nothing to do but rotate. Plant something they cannot grow upon — something that will starve tliem out ; there is no other way of killing them out of the ground. 5. Seek continually for resistant varieties and strains. With every- body on the lookout for these valuable variations, we may hope for more rapid progress in the control of fungous diseases of plants. 6. Observe general soil and plant hygiene. With the soil mellow and well drained we may minimize danger from root rots and damping-off fungi ; with plants well spaced to let in sunlight and allow free circu- lation of air, or pruned with this in view, and witli fruits thinned so as not to touch, we may greatly reduce danger from air-ltorne spores. Every cominuiiity organization, rnral or suburban, ougbt to have a committee on fungous diseases of plants aiid their practical control. The local class in biology might well be the laboratory right arm of such a committee. By working out cooperative plans, thoroughly agreed upon, which might spread from neighborhood to neighborhood as they were de- veloped and perfected, many of our. Avorst fungus enemies might be completely stamped out. No real estimate of the loss caused by them has ever been even attempted. We do not know enough about them. Duggar's guess of 1500,000,000 a year is very low, and, while it might approximate the losses to tlie large markets and channels of trade, we must certainly add to this all the damage to the home garden and orchard, with the labor and expense of fighting fungi in them. The class in civic biology which gives us even a first attempt at a detailed account of the expenses and losses chargeable to fungous diseases of plants in any community will mark a distinct forward move in tliis field. CHAPTER XXI BACTERIA Size. Bacteria, the smallest plants known, range in size from ultramicroscopic to 6 microns thick by 80 microns long. Even the largest single bacterium known is far too small to be seen with the unaided eye, and for the smaller species, like the germ of grippe. Bacillus influenzce, which is .3 />«, thick by .75 fjb long, we might have 2,867,417,289 spread in a single layer over one square inch of finger tip, and the smear might be even 100 germs deep, that is, contain 286,741,728,900 bacteria, and still be invisible to the eye and too thin to feel. Form. Bacteria appear under the microscope as spherical (the micrococci), as slender rods (the bacilli), and as forms bent like commas or twisted into spirals (the spirilla). Humorously they are said to resemble " balls, cues, and corkscrews." Distribution. Bacteria are everywhere in nature except in the air at high altitudes, over perpetual snows and over mid- ocean, in the deeper layers of sand or clay soils (they may be carried to almost any depth and almost any distance by streams in crevices of rocks), and, most important of all, in the blood or sap and internal tissues of healthy animals and plants. Bacteria of the air. Bacteria are blown about as free dust with every current of air. The table on the next page, made in France from data collected monthly for ten years, shows the variation in number of bacteria in the air of city and country at different seasons of the year. 218 BACTERIA 219 j Country Bacteuia City Bacteria Winter Spring 170 295 345 195 250 4,305 8,080 9,845 5 6H5 Autumn Average 6,975 Bacteria of water. Streams ordinarily contain about 500 bacteria per cubic centimeter, collected from the air and soil over the area drained. The river Seine, as it enters Paris, has about 300 bacteria per cubic centimeter, but after it receives the sewage from this city it contains 200,000 bacteria per cu- bic centimeter. The supposed self-purification of streams is found to be mainly due to dilution. Experts are impounding running water in reservoirs previous to supplying cities, since bacteria disappear from still water. JNIicroscopic organisms (plankton) upon which young fishes feed are found in greater abundance in quiet water, and it is thought that they in turn feed upon bacteria. Water in wells varies greatly in number of bacteria. Arte- sian wells are practically free from them ; ordinary wells may contain from 1000 to 8000 bacteria per cubic centimeter. Ice varies in number of bacteria according to water from which it is taken. Clear ice from the Hudson River contained 398 bacteria per cubic centimeter, while its snow ice contained 9187. Why ? Bacteria of the soil. The number of bacteria of the soil varies with the amount of moisture and organic debris. Su- perficial layers contain from 10,000 to 5,000,000 bacteria per gram; if polluted with organic debris, they may contain as high as 100,000,000 per gram. The number of bacteria di- minishes rapidly as we pass down into the earth ; at a depth of from ten to fifteen feet few if any can be found. This is the reason that in many cities water is passed through sand filters before it is used for drinking purposes. 220 CIVIC BIOLOGY Reproduction in bacteria. Bacteria multiply by division, which is even more simple than the budding of yeast. The cell, when mature, divides transversely into equal halves. Under favorable conditions a bacterium may divide every twenty minutes to half an hour. Can you calculate the progeny of a single bacillus for twenty-four hours ? Bacteria do not grow and reproduce without food, and their astonishing power of multiplication helps us to understand the altered condition of milk and meat if kept in a warm place for even a few hours. Some species develop spores within the cell and these are much more difficult to kill than the bacteria themselves. Conditions favorable for the multiplication of bacteria. Like other plants, bacteria demand food, moisture, oxygen, and warmth for growth. Remove any one of these conditions and they will either cease to multiply or die. Moisture. Bacteria grow only in liquids or moist sub- stances. Dry foods and those containing less than 20 or 30 per cent of water they cannot attack. Drying weakens and kills many bacteria. Spores, however, are much more resis- tant to continued drying than the vegetative or growing cell. Why should houses not be allowed to become damp? Why is meat salted and dried? Why is canned fruit sealed? AVhat influence has sugar in preserving frtiit? Why are such foods as molasses, condensed milk, flour, seeds, and grain bacteria-proof? Temperature. Temperature affects growth of bacteria. As in higher plants, there is a temperature known as the optimum at which each species thrives best. A tubercle bacillus grows within a range of 5 degrees, while a few other species can grow anywhere within a range of 50 degrees. Bacteria do not multiply during the time they are exposed to low temperature, but their vitality is not affected ; the tu- bercle bacillus has been exj^osed to a temperature of liquid air BACTERIA 221 (—190° C.) for periods varying from six hours to forty-two days without kilhng it. The retardation of bacterial growth in low temperature is of importance from the public-healtli standpoint, since it makes possible the shipping and temporary preserving of perishable foods in cold storage. Heat in sufficient amount kills all bacteria whether in the spore or vegetative state. Steam heat is more effective than dry; a few minutes of steam heat at 120° C. will kill spores that would take 180° C. of dry heat to destroy. Light. Contrary to the effect produced upon green plants, light has an unfavorable action upon bacteria. Bright sunlight serves to kill the vegetative cell and weakens the spores ; diffuse light retards growth ; in the absence of all light they grow best. This destructive action is intensified by moisture and fresh air. Oxygen. Pasteur was the first to demonstrate that some bacteria live without free oxygen. He divided all bacteria into three classes : aerobic, those species that can grow only in the presence of air; anaerobic, those that can grow only in the absence of air ; and facultative, those that can grow either with or Avithout air. Bacteria that, grow in the inner tissues of the body of a plant or animal are examples of anaerobic species ; they do not grow without oxygen, but get a supply by breaking down organic substances that contain it. The majority of bacteria are aerobic, as evidenced by the many cases of decay which begin on the surface and work toward the center. Work of bacteria. Like other fungi, bacteria are parasitic (attacking living plants and animals), saprophytic (feedhig upon dead or waste animal or plant matters), and symbiotic (living in plants to the mutual benefit of bacterium and plant). Because some species can attack living tissue and produce disease, all bacteria have come to suggest disease to the popular mind. This reputation is as unjust to the 222 CIVIC BIOLOGY saprophytic bacteria as it would be to condemn all higher plants because a few of them are poisonous. In general, sap- rophytic bacteria do no more harm than dust if breathed, or than vegetables if eaten. Nitrifying bacteria. Certain bacteria of the soil are symbi- otic upon the roots of leguminous plants, such as clover, alfalfa, beans, and peas, and cause tubercles to form. These bacteria gain entrance through the root hairs of the plant and cause smooth young roots to as- sume a nodular appear- ance (Fig. 104). Experiment shows that if a legume, notably clo- ver, is grown upon soil of known composition, a part of which has been ster- ilized (baked), the crop upon the un sterilized soil will be notably larger and the soil will have nitro- gen added to it. .These bacteria are important, since they can fix the free nitrogen of the air and give it to tlie soil in the form of nitrates. The benefit to the soil result- ing from clover cropping was discovered and practiced by farmers long before the cause was known. Much experimental work is being done with these nitrifying bacteria, and pure cultures are being sold to inoculate soil that does not contain them. To prevent extravagant and mis- leading claims of dealers, the United States government has issued the following statements ; " No beneficial results can be Fig. 104. Clover plant with many bacterial nodules on roots BACTERIA 223 expected for a particular crop if the bacteria for the crop are already in the soil. But little, if any, benefit can be expected from the use of these bacteria if the ground is decidedly in need of other fertilizers, such as phosphates, potash, and lime. But little, if any, benefit can be expected from inoculation if the soil is already rich in nitrogen." Carefully wash the roots of different clover plants. Are the nodules of nitrifying bacteria present? Are they found upon alfalfa and peas in your region? Are pure cultures of these bacteria sold in your state? Read the state and government bulletins upon these bacteria. CHAPTER XXII BACTERIA CONTINUED: LABORATORY METHODS Apparatus and material. To grow bacteria in the labora- tory the following apparatus and material are necessary : a steam sterilizer, hot-air sterilizer, two platinum needles^; test tubes, Petri dishes, absorbent cotton, litmus paper, sheet gela- tin, agar-agar, extract of beef, potatoes, caustic soda solution, and hydrochloric acid. Gelatin medium. Dissolve in 1000 cubic centimeters of distilled water 10 grams of peptone, 5 grams of common salt, 2^ grams of beef extract, and 100 grams of sheet gelatin, and place in the steam sterilizer until dissolved. ^ Let the mixture cool to 55° C. (you can hold it in your hand) and add a teaspoonful of albumen dissolved in cold water, or the whites of two eggs. Boil until the liquid looks clear.^ Line a funnel witli wet absorbent cotton or with filter paper designed for gelatin or agar-agar filtration. Pour the gelatin mixture into the funnel and catch in a sterilized flask. Place in a steam sterilizer. If the funnel is kept thoroughly warm, the gelatin will pass through the filter in about an hour. Test the gelatin with litmus paper. It will be found to be acid. Add a weak solution of caustic soda to it, drop by drop, until blue litmus paper does not change 1 Cut platinum wire (No. 27) into two-inch lengths. Fuse one end of each into a glass rod, and bend the free end of one of the needles thus made into a small loop, to be used in measuring drops in liquid cultures. 2 A portable sheet-iron oven and an ordinary steam cooker may be used if necessary. 8 A fact that must be borne in mind in preparing gelatin is that its gelat- inizing power is injured by prolonged heating during the process of prepa- ration or sterilization, and is lost immediately when heated to 140° C, 224 BACTERIA 225 color. Pour about one and one-half inches of gelatin into each test tube and plug with cotton. Sterilize the tubes twenty minutes for three consecutive days, so as to kill all spores. Agar-agar medium. ^lix the same as the gelatin medium, using 15 grams of agar-agar in place of the 100 grams of gelatin, llie preparation of agar-agar medium, however, is more troublesome than the gelatin. Agar-agar does not dis- solve easily and is difficult to filter. To obtain a quick result it is best to perform the filtration in parts. If the funnel, lined with absorbent cotton, is well heated, about one half of the agar-agar mixture will have passed through the filter in fifteen minutes. Remove the funnel and reboil the remaining agar- agar and pass through a fresh filter. Repeat the process until the mixture is filtered.^ Potato medium. Pare the potatoes and cut with a cork borer of suitable size for the test tube. Divide the cylinders into two-inch lengths and then cut diagonally across. Place the '' potato slants " thus prepared in water for several hours, to extract the product which turns them black when exposed to air. Put into test tubes, slant side uppermost, plug, and sterilize in a steam sterilizer for twenty-five minutes at 100 C. for three successive days. A small piece of glass rod placed in the bottom of the test tube holds the potato above the condensed steam. Rules and methods of manipulation. (1) Learn as early in the course as possible that all dishes should be washed and sterilized in the hot-air sterilizer before using. All micro- organisms are killed when they are heated as follows : three hours at 150° C, or until paper is brown ; one half hour at 160° C; one fourth hour at 170° C; one minute at 190° C. (2) Before sterilizing, wrap the Petri dishes in papei* and 1 If time is limited, obtain the prepared gelatin or agar-agar from a local hospital laboratoiy or board of health, or order from a regular dealer in such supplies. 226 C;i\IC BIOLOGY plug the test tubes. To make plugs, tear a strip of cotton about two inches wide and as long as needed, fold length- wise, and roll into a plug. Insert this not more than half an inch into the test tube. Cotton plugs are quite generally used in bacteriological work, since they allow a free circu- lation of air and prevent the entrance of germs. If material Fig. 105. Preparing culture media Photograph by the author p -- ^ ^ is properly sterilized and plugged with cotton, it will keep indefinitely. (3) Do not open the hot-air sterilizer until the temperature is down to 40° or 45° C. It is preferable to leave the dishes undisturbed in the sterilizer until used. Before planting (inoculating) your culture media with bacteria observe the following: Unless otherwise directed, always inoculate media with platinum loop or needle. (1) Heat the wire in the flame just before and immediately after using. (2) Avoid having BACTEKIA 227 currents of air in the room. (3) Upon opening a culture medium for inoculation, pass the mouth of the tube through the flame (flaming) ; if it has stood for some time, flame the cotton before opening the tube. (4) Never allow the tube end of a plug to come in contact with anything while re- moved from the tube. (5) If a plate culture is to be made, melt the gelatin in a test tube (placed in warm water) and pour into a ster- ile Petri dish. If Petri dishes are not available, test tubes may be substi- tuted, provided the gelatin in them is allowed to cool Avhile they are lying in a nearly horizontal position. (6) In- oculation should not take place before the gelatin hardens, unless germs from a liquid are to be grown. In this case the gelatin is inoculated in the test tube and then poured into the Petri dish. (7) Unless otherwise directed, all cultures that have been inoculated should be kept in the dark, or in dif- fused light and at room temperature. (8) If possible, duplicate each experi- ment, using both potato and gelatin media. Note appearance of growth in each case. Label and keep careful records of each experi- ment. (9) After your experiments are finished, do not allow the media to dry; place all dishes in water and boil for fifteen or twenty minutes before cleaning them. Experiments for bacteria of the air.^ (1) Expose a Petri dish of gelatin for five minutes in the laboratory before the class enters. (2) Expose another for the same length of time 1 Each member, or group of members, of the class should perform one or more of these experiments. Fig. 106. Exposing dishes Petri Photograph by the author 228 CIVIC BIOLOGY in the same room just after the class has left. (3) Expose a Petri dish of gelatin in a room for five minutes immediately after wiping up the dust Avith a dry cloth or after using a feather duster. Compare this plate with one that was exposed for the same length of time in a room immediately after it had been dusted with a damp cloth. (4) Expose a plate in a living room for five minutes and compare with the air in the yard. (5) Compare the number of bacteria in the air upon the ground with that of the first and fourth stories of the same building. Is it true that a child breathes less pure air than a man ? Is it more desirable to sleep upstairs, as far as air is concerned ? (6) Expose a plate of gelatin in a busy street before and after it has been sprmkled, or before and after a rain. (7) C'ompare the number of bacteria in a well-cleaned street with the number in one that is not cleaned. What do you think of the system that cities are using for flushing their streets ? (8) Compare as to number t)f bacte- ria the au' before and after a snowstorm or rainstorm. Inocu- late plates with rahi or fresh snow. Keep these experiments in a drawer in the laboratory. In a day or so count the colonies of bacteria and record results. (9) Sweeten and cook fruit, such as apples, in a test tube. Plug with cotton. Does canned fruit keep if air is present and bacteria are excluded ? (10) Discuss the desirability of having children's playgrounds upon the roofs hi large cities. Experiments for bacteria of water. (1) Make a culture of water from a stream (dip your platinum loop three times) and compare with the same amount of water from the reser- voirs and lakes of the locality. (2) Compare the water above and below the point where the sewage is emptied. (3) Com- pare the different drinking waters of the locality. (4) Make cultures of water that is rich in organic debris and compare with the same water that has been boiled for fifteen minutes. (5) Filter some of the water used in the above experiment JLV(TERIA 229 through several inches (twelve or fifteen) of clean sand. Is a sand filter effective ? (6) Make cultures of milk. How does fresh milk compare in the number of its bacteria with that which has stood for some time ? (7) What is meant by Pasteurizing milk ? If possible, visit a milk station where milk for babies is sold. What measures render it safe ? Fig. 107. Inoculating gelatin tubes with platinum loop Note the way in which cotton plugs are held between the fingerf Additional experiments. (1) Scrape the surface of a silver coin with a sterile knife and make a plate culture. Compare with cultures made from copper coins and paper money. No paper money is used in the Hawaiian Islands because of the danger of transmitting disease. (2) Make plate cultures from the surface of a pencil that a child has used for some time ; from the edge of a common drinking cup, door handle, straps 230 CIVIC BIOLOGY in a street car. (3) Make a culture from a dishcloth that is washed and boiled once a day, and from one that is not. (4) Compare the number of bacteria in rancid and fresh butter. (5) Allow a fly to walk across a plate of sterile gelatin ; record results. (6) Make a stab culture by running a straight platinum wire, with germs upon it, down through several inches of sterile gelatm in a tube. Upon removing the wire the gelatin closes around the germs left in its track, and serves to cut off the air supply except at the surface. Do you find three classes of bacteria growing in the culture ? The excretions of bacteria render the most favorable medium unfavorable. In general, bacteria do not grow as well upon acid as upon slightly alkaline media. (7) Make a culture from the dust of a dark corner of a room; from a surface in diffused light; from one in bright sunlight. Can you think of more favorable conditions for the growth of bacteria than that offered by the mouth ? How can you keep your teeth from being destroyed by them ? (8) Inoculate a plate with clean- ing of a finger nail, dandruff, single human hair, cat hair. (9) Breathe into a gelatin tube without touching the lips to the glass; make a plate culture. Can the breath carry bac- teria ? (10) Make a plate culture of some of the substance that has gathered upon the back of the teeth. (11) A bacillus has a characteristic growth upon a culture medium. From the appearance of the colonies do your experiments show that you have grown different species of bacteria ? Can you see that by selecting a species of bacteria and hioculating a fresh cul- ture with it, and then from it again selecting and inoculat- ing a fresh medium, you would soon obtain a medium with a ''pure culture" of that species of bacteria? (12) Can you now explain the need of such rules and precautions as are given in the early part of this chapter ? CHAPTER XXIII CON^TROL OF BACTERIAL DISEASES Aristotle (384-322 b.c.) instructed Alexander the Great to have his sol- diers boil their water in order to prevent epidemics of disease in camps. JPossibly to this bit of practical biology Alexander ovv^es his conquest of the world. Advertendum etiam, siqua erunt loca palustria, et propter easdem causas, et quod (arescunt) crescunt animalia quaedam minuta, quae non possunt oculi consequi, et per aera intus in corpore per os ac nares perveniunt atque efficiunt difficilis morbos.i — Varro (b.c. 116-27), "De Re Rustica," Lib. I, 11-12 (Keil, 145) Already in his studies on silkworms, Pasteur's first experience in the domain of disease, the dawn of a new era in the contest of man with con- tagion opens up before him. He says: "II est au pouvoir de I'homme de faire disparaitre de la surface du globe les maladies parasitaires, si, comme c'est ma conviction, la doctrine de la g^n^ration spontan^e est une chim6re."2 — Frankland, ''Life of Pasteur," p. 123 Bacteria and disease. The majority of bacteria are harm- less or beneficial. A few are venomous, as are a few species of snakes, fishes, trees, or mushrooms. The venomous bac- teria strike plants, animals, and man just as really as do lead bullets, and wound and kill in essentially similar ways. The notion is current that bullets hit the fittest, while bacteria seek out the unfit, but there is not much ground for this 1 '' One should be on guard, if there should be any swampy. places, both for the same reasons and because there grow certain minute animals, which the eyes cannot perceive, and which, permeating the air, enter the body through mouth and nostrils and cause serious diseases." — Professor S. F. Dunn, University of Oregon, Translator 2 "It is within the power of man to cause to disappear from the surface of the globe the parasitic diseases, if, as is my conviction, the doctrine of spontaneous' generation is a chimera." 231 1900 1901 1902 1903 1904 1905 1906 1907 1908 1909 1910 1911 1912 Fig. 108. Death rate per 100,000 population in the registration area of the United States From the Census, Mortality Statistics, 1912 232 CONTROL OF BACTERIAL DISEASES 233 idea.i Ignorance aside, there is no more reason for allowing ourselves to be bitten by bacteria than by rattlesnakes. About two people die from snake venom annually in the United States; 20,000 die yearly in India from snake bite, because cobras are accorded superstitious protection. We religiously preserve our bacteria, with the filth in which they thrive and the flies that distribute them ; the Hindus, their relatively harndess snakes. A few of the more familiar germs, with the disease and death they are causing, are presented in the table on page 234. When we all know how to kill and avoid these bacteria, as well as we know how to deal with rattlesnakes, we may be as free from them as we are from the snakes. All must know and each must do his part, for one ignorant person can scatter bacteria by the million from j\Iaine to California. The table is by no means complete. In the next chapter we shall study a similar list of diseases caused by parasites of animal origin. There is another list, known to be infections, — smallpox, yellow fever, scarlet fever, measles, spotted fever, and foot-and-mouth disease, — the specific causes of which have baffled all attempts to discover. Still another class of ailments, noninfectious, chronic and organic, — of the heart and arteries, brain and kidneys, — of heavy and increasing- fatality, may have to do with organs weakened by parasitic attack. Finally, we have no statistics of the number of the wounded, the weakened or crippled, and the number of minor ailments, very numer- ous and of constant occurrence, that impose their burdens of sheer misery — the millions of cases of rheumatism, tonsillitis, boils, felons, carious teeth and toothache, indigestions, diarrheas and dysenteries, and "colds," most wretched of all, probably not less than 200,000,000 of them a year. When we add to all this the bacterial diseases of animals (hog and fowl choleras, bovine, avian, and other tuberculoses and pneumonias, white diarrhea of chicks and foul brood of bees, 1 " Neither regularity of life nor bodily strength was any preservation against it. The strong and the weak were equally struck down ; and death spared not those of whom care was taken, any more than the poor, desti- tute of all help.", (The fleas of that time bit all alike.) — Gasqiet, "The Black Death," p. 12 234 CIVIC BIOLOCY 02 ^ -Ti ^ o C o C a oj >. cS K f> .VJ - O •^ cS O 'o ;r3 ^ '^3 •-' .2 " q -^ .^ ^ c .^ , r- r- OD Q 02 '-t-i t! '^ s t-^ +j ^^ .ur t? o ^^ fc-. G G ^ ^ O O H W y O ^ ^ PQ >^3 ^^ m G p. -a 2 a> G o J « O 8 §1 tl k; k; 5q ^ !^ k5 Ph k5 a; ^ CONTROL OF BACTERIAL DISEASES 235 anthrax and glanders, and many others) and the long list of bacterial diseases of plants, already briefly considered, we begin to realize that the very edge of the struggle for existence lies between mankind and the bacteria. The three questions. The following questions apply to the parasitic diseases — bacterial, protozoan, vermian, and all the rest. When Pasteur was "wasting his time" disproving spontaneous generation, one of his friends wrote: "He makes me uneasy, he does not recognize the limits of science, he only loves insoluble problems." Now that we know that '' la gejneration spontanee est une cMmere^^ the problem of the control of disease becomes the comparatively easy one of preventing the spread of the living germs from the sick to the well. In every case of contagion or infection the germs escape alive from the body of the sick, are carried to the well, and gain entrance. Therefore the three fundamental questions are: 1. How do the germs of each disease escape from the body of the patient? 2. How is each kind of germ carried ? 3. How does each kind of germ gain access to the body? Paths of escape. Parasitic germs of the lungs, nostrils, throat, or mouth (of diphtheria, tonsillitis, pneumonia, tuber- culosis, rhinitis, bronchitis, and influenza, as well as stomach and intestinal diseases that involve vomiting — typhoid fever, enteritis, and cholera) escape with any discharges from mouth or nose. Careless coughing and sneezing may scatter the germs over anything or anybody within a distance of about six feet. Spitting in any public place is an abomination, and laws against it should be rigidly enforced in the interests of public education as well as health. Bacteria from the digestive and renal-reproductive organs pass out with the dejecta — dysentery, choleras, typhoid. Typhoid bacilli have also, been found in the perspiration. 286 CIVIC BIOLOGY Germs circulating in the blood are usually drawn off by blood-sucking insects, ticks, or mites ; malaria and yellow fever, by mosquitoes ; typhus fever, by bod}' lice (and per- haps by fleas and bedbugs) ; plague, by fleas (possibly also leprosy) ; typhoid, by bedbugs ; Texas fever and spotted fever, by ticks; infantile paralysis (?) and anthrax, b}^ the Micrococci Bacilli Spirilla Grippe Diphtheria Fig. 109. Pathogenic bacteria modeled to scale in plasticene (niicra = centimeters), magnification of models being 10,000 diameters A suggestion for a laboratory collection. Mount in insect cases under glass. Photograph by the author stable fly ; and sleeping sickness, by one of the tsetse flies. Diseases marked by lesions of the skin — measles, scarlet fever, smallpox, and probably dandruff and eczema — may escape with the scales of cuticle or the contents of blisters or sores. How living disease bacteria are carried. The greatest barrier to the learning of truth is apt to be a firm belief of an error. No set of ideas has cost the world more misery, suffering, and loss than false notions, prejudices, and superstitions re- garding the transmission of diseases. First they were carried CONTROL OF BACTERIAL DLSEASES 237 by angry gods, demons, and witches ; next, by the air as miasms and effluvia ; then, by fomites m dust of clothing or merchandise ; and, finally, we have come down to the sure evidence of science that contact infection, chiefly by the hands, accounts for almost all the spread of common diseases, and insects, by contact or inoculation, for most of the rest. Air not an important carrier. Just now the air is rapidly losing all its terrors, smallpox being the only disease which may possibly, though not probably, be carried from house to house by this agency. (This does not mean that insects that fly may not transmit many infections by contact.) Chapin puts the case carefully and sensibly as follows: Only a few authorities now assert that disease is carried by the atmosphere outside of dwellings, and this assertion is made only in regard to smallpox. . . . Infection by air, if it does take place, as is commonly believed, is so difficult to avoid or guard against, and so universal in its action, that it discourages effort to avoid other sources of danger. If the sick-room is filled with floating contagium, of what use is it to make much of an effort to guard against contact infection? If it should prove, as I firmly believe, that contact infection is the chief way in which the contagious diseases spread, an exaggerated idea of the importance of air-borne infection is most mischievous. It is impos- sible, as I know from experience, to teach people to avoid contact in- fection while they are firmly convinced that the air is the chief vehicle of infection. . . . Without denying the possibility of such infection, it may be fairly affirmed that there is no evidence that it is an appreciable factor in the maintenance of most of our common contagious diseases. AYe are warranted, then, in discarding it as a working hypothesis and devoting our chief attention to the prevention of contact infection. It will be a great relief to most persons to be freed from the specter of infected air — a specter which has pursued the race from the time of Hippocrates ; and we may rest assured that if people can as a conse- quence be better taught to practice strict personal cleanliness, they will be led to do that which will, more than anything else, prevent aerial infection also, if that should in the end be proved to be of more importance than now appears. — Chapin, "Sources and Modes of Infection," p. 268 ff. 238 CIVIC BIOLOGY Even the air of the sick-room has no dangers if modem methods for bacteriological cleanliness are strictly observed — that is, if all waste matters or discharges go straight from the patient into the fire or sterilizer, and if the rubber gloves with which all handling of the patient is done are disin- fected immediately after using. Except by the cough spray a bacterium cannot leave a moist surface, and by the above precautions no living germs can become dry and so enter the dust of the room. Fomites. " Persons and not things transmit diseases." This slogan is coming more and more to dominate the whole .field. Ships, in numbers, have been sunk, cargoes and all, to insure against purely imagmary fomites. No sharp line can be drawn between infection by contact and infection by fomites. Contact infection implies the more immediate transfer of germs, as in shaking hands, exchanging pipes, swapping gum, using the same drinking cup or towel, inter- changing dishes at successive meals, touching foods, candies, fruits, etc. with unwashed hands ; while the theory of fomites implies infection by germs carried alive and virulent in cloth- ing, merchandise, baggage, and mail matter for long distances and during considerable periods of weeks or even years. As we shall see in the next paragraph, when we begin to pay attention to them, there are so many ways by which bac- teria are carried fresh and green from mouth to mouth, by direct or indirect contacts (and not only from mouth to mouth but from dejecta to mouth), that it is sheer dis- honesty to crowd our own responsibilities for really inex- cusable contacts over onto the theory of fomites. If common notions of fomites were true, we should have to arm our postal mail clerks with fumigator masks and rubber gloves or bury the whole force every night. As a matter of fact, bank tellers, handling " dirty money " all the time, mail clerks, handling letters sealed and stamped in everybody's CONTROL OF BACTEEIAL DISEASES 239 saliva, second-hand clothing dealers, and even rag sorters, all live in average freedom from infections. Doty's testi- mony on this point is as follows: The author has .carefully investigated the influence of money as a means of infection. The results show that those who are constantly handling money, such as bank officials, do not contract infectious dis- eases any oftener than others. The Treasury Department at Washing- ton furnishes exceedingly valuable information on this subject. Here large quantities of filthy and offensive paper money are being constantly handled and rehandled prior to destruction, and not the slightest evi- dence has been presented at that place to show that infectious diseases are transmitted by this material. Than this, no more important or con- clusive evidence on this subject can be presented. — Doty, *' Prevention of Infectious Diseases," p. 10 Even epidemics in schools — of measles, diphtheria, and scarlet fever — have been found by the medical examiners of New York City to be caused by mild or incipient cases and by unsuspected "carriers " — that is, by contacts of persons and not of things. Terminal disinfection (fumigation or disinfection at termination of a disease or of quarantine) was abandoned in Providence in 1905, "except in those very few instances in which the family was willing to wait for two successive negative throat and nose cultures from each of its mem- bers," the idea being that it was a waste of public money to disinfect rooms while members of the family were carrying living diphtheria germs, and there has been no marked increase of recurrent cases. "The New York City Health Department has given up fumigation after cases of infectious disease, as a costly procedure, the inutility of which has been well established." ^ A more conservative opinion is expressed by an eminent authority as follows : " Though the results obtained in some cities since abandonment of terminal disinfection after certain diseases seem to show that heretofore much useless disinfection has been done, it is not felt that the evidence thus far adduced fully justifies its dis- continuance." ^ The idea underlying this j^osition is that if terminal disinfection saves even a few infections, it should not be entirely aban- doned. The above is sufficient to show that this important matter is still an open problem ; for the best light upon which we should consult 1 American Journal of Public Health, Vol. I (1915), p. 166. 2 H. S. Hasseltine, United States Public Health Reports (July, 1915), p. 2060. 240 CIVIC BIOLOGY our local health authorities (when possible) and the best current health literature. All are agreed that in case of gross uncleanliness or of new, rare, and exceptional infections, the means of transmission of which may not be known, terminal disinfection is advisable. It may take years, or even centuries, of hard work, but nothing can ever take the place of exact knowledge of the definite means by which each parasitic germ is harbored or transmitted. Knowing this, we now exterminate the guilty mosquito instead of sinking the ship to prevent spread of yellow fever, and we pay attention to the rats and fleas in case of plague instead of burning the village, inhabitants and all. Contact infection. It was a lesson, never to be forgotten, when his family physician once confessed to the writer that he had caused the death of a young mother by failing to scrub the little-finger edges of his hands carefully enough. Upon such honesty as this we can depend for progress of both science and practice. Could we be as honest with our own hands for one day, we might eacli learn a lesson of life- long value to our own ideas of rational cleanliness. Suppose we mark with red ink every spot on fingers or hands moist- ened by saliva or mucous secretions from the nose, and with black ink all areas soiled by contacts with things which it would be utterly disgusting or dangerous to put into the mouth — the fly we crush, the cat we touch (that has licked her own saliva over her fur), the dead mouse we have taken from a trap, the pus from a pimple or sore, and so down the list. If we did this for half a day even, could we ever again go to the table without obeying the scriptural injunc- tion to wash the hands before breakhig bread ? And we would not be content with ceremonial touclnng of water, but Avould wish to scrub them with soap until all the ink spots were off. If such definite instruction were universal, we might not have examples like the following; Spread of gonococcus infections, persistent and impossible to prevent or trace, in the New York City Babies* Hospital, uncontrolled for sev- eral years by laborious disinfection of buildings and equipment (after CONTROL OF BACTERIAL DISEASES 241 finally discovering that the same night nurse tended the infected cases and new infections in a distant ward) ceased completely when tlie nurses began disinfecting their hands after attending each case. — Holt, New York Medical Journal, A'ol. LXXXI (1905), p. 521 Men detailed as hospital orderlies were, after they had performed the duty of emptying bedpans, seen to go directly to their meals without washing their hands, and even to distribute food to their comrades.^ — Chapin, p. 120 Thus, at one of the finest hospitals in this country, with separate wards for scarlet fever and diphtheria, a considerable number of cases have arisen in the general wards. The germs were supposed to be air- borne, as it M^as said there was no other possible avenue of infection. AVhen I saw the head nurse lick her finger to facilitate turning the bed- side charts of diphtheria patients, I suspected that the princii)les of medical asepsis had not been entirely mastered. — Chapix, p. 105 . The superintendent of another hospital invited another visitor and myself to eat ice cream from the same spoon with himself, which spoon was then replaced in the freezer which w as to supply the wards. I Mas most of all impressed with the fact that at the International Congress on Tuberculosis in 1908 a large number of the readers of papers moistened their fingers with their tongues when turning the pages, and in each of the sections only one drinking glass was provided for all the speakers ; and this continued for a day or two without protest. — Chapix, \). 1«)5 The following observations were made by the autlior in 1915. 1. Stopped to buy candy in order to observe "home manufacture"; saw elderly man molding nut drops lick off his fingers and go on mold- ing. Threw candy away. 2. Asked for pound of ]>reserved ginger at a fine confectionery store ; waitress clawed it out of tray with hands. Paid for it and threw it away. 3. Called for glass of milk at railway-station lunch counter; swarthy foreigner removed cap from quart jar, put his dirty hand over bottle, turned it bottom up and shook it violently, scraped palm of hand on mouth of jar, and poured out the glass. He was told to drink it himself. 1 From a description of an army typhoid epidemic. 242 CIVIC BIOLOGY 4. Observed^ flies swarming on crates of raspberries and black- berries, absolutely open and unprotected (caught about sixty flies with one sweep of the hand over such a crate). Carriers and contact with food. Typhoid Mary was dis- covered by Soper in 1906. She was apparently healthy, but wherever she served as cook typhoid fever was sure to fol- low, and she was found to be alive with virulent typhoid bacteria. She had already caused several small and at least one large epidemic. From 1907 to 1910 Mary was detained in the isolation hospital of the New York Board of Health and then was released upon her promise to change her occu- pation. Early in 1915 an epidemic of 25 cases broke out in one of the New York hospitals, and there in the kitchen, under an assumed name, was found Typhoid Mary. About 4 per cent of those who recover from the disease remain as typhoid carriers, either continuously or intermit- tently, and some may not even know that they have ever had typhoid at all. For some unaccountable reason there are about five women carriers to one man. A typhoid epi- demic occurred at Hanford, California, !March, 1914, the study of which by the health officers proved most instruc- tive. A church dinner, of which 150 partook, resulted in 93 cases and 3 deaths. The infection was traced to a woman who had cut the bread and prepared a dishpan of Spanish spaghetti. She had nursed her daughter through typhoid thirty-five years before, but did not know that she herself had ever had the disease. In order to test the matter a dish of spaghetti, not so large, was similarly prepared, and, although baked much more thoroughly than that served at the dinner (until the top was brown, the points on the sur- face were charred, and the edges were boiling furiously) living typhoid bacilli were found within half an inch of the 1 In a public market, Washington, D.C., July 3, 1916. CONTROL OF BACTEEIAL DISEASES 243 surface and at the center of the mass they were swarming, and the temperature there was only 28° C. This proved that " ordinary baking merely incubates the interior of these masses of food." ^ At a Gettysburg soldiers' reunion one of the men " not feeling very well" was assigned mess duty. As a consequence (probably of his handling the bread) fifty-five of the company developed typhoid. Naturally extreme danger attaches to contact infection of foods in which bacteria may multiply — lobster, shellfish; cooked meats, and es- pecially milk. Formerly epidemics following the eating of these things were explained on the theory of "ptomaine poisoning" — that is, that poisons (ptomaines) were formed by bacterial growth in the substance, which were not destroyed by heat. Jordan says of this : " Many of the epidemics of 'meat poisoning ' etc. are now known to be due to infection with a specific microorganism rather than to the action of a formed poison." 2 Milk is a most favorable culture medium for bacterial growth, and naturally many epidemics are traced to it. Chapin gives the follow- ing figures : 315 outbreaks of typhoid, 125 of scarlet fever, 51 of diph- theria, and 7 of tonsillitis (epidemic sore throat). Immediate report to the board of health of the milk route on which a case of illness occurs makes it possible to nip many an epidemic in the bud, a visit to the dairy generally revealing the source of the infection. Recent outbreaks of typhoid on two milk routes in Hartford, Con- necticut,— 12 cases in September, 1914, and 34 cases in November, — were traced to the same carrier, an occasional milker, who had moved from one dairy to the other. All the typhoid, 21 cases, in a Minnesota town for five years was traced to one carrier in a dairy. ^ An epidemic of diphtheria in Lincoln, Nebraska, of 110 cases and 2 deaths (97 received antitoxin promptly, and none of these died) was traced to a diphtheretic " sore throat " of a milker. The money cost to the community of this '* trifling sore throat " is estimated at |10,000, in addition to the suffering, labor of nursing, and the 2 deaths.* ^ Sawyer, Journal of the American Medical Association, 1914, p. 1537. 2 Jordan, General Bacteriology, p. 101. 8 H.W. Hill, American Journal of Public Health, Vol. IV (1914), p. 667. 4 Wait, '^ Report of Milk-borne Epidemic of Diphtheria," American Journal of Public Health, Vol. IV (1914), p. 418. 244 CIVIC BIOLOGY Clean milk. For many, possibly for all, coiimmnities uo better health- conservation work could be undertaken than solving, each member of the class for his own home and the whole class for the home commu- nity, the problem of safe and clean milk. Milk is safe when all disease germs are kept out of it, and it is clean when free from filth of all sorts, usually indicated by numbers of other bacteria. As secreted by healthy cows, milk is pure, and by observing hosi)ital-operating-rooin precau- tions it can be kept so. ^ Von Behring's statement that milk should not -1)6 used for infant feeding if it contains more than 1000 bacteria per cubic centimeter is rarely lived up to. Boston's standard of purity (which Spargo thinks is worse than no standard at all) allows 500,000 bacteria per cubic centimeter, and " certified milk " may run as high as 10,000 bacteria per cubic centimeter. Secure copies of specifications for local certified dairies. '^ If possible, have a committee of the class, or each member, work up the technique of making the bacterial count and examine local milk su[)]>lies.* We have been too long scoring dairies according to buildings and equipment, and nothing could be more convincing for the truth of Dr. North's contention that dirty milk is 90 per cent due to dirty or ignorant dairymen than his demonstration in ten Kelton dairies. Ten trained Oxford dairymen were shipped over to Kelton in time to do the evening milking in ten of the dirtiest Kelton dairies, with the result shown on the next page : bacteria in the milk reduced from millions to less than 10,000 per cubic centimeter, in all but Xo. 0, a most in- structive exception. ^ Four things necessary to production of clean milk : 1. Milking with dry hands into covered pails. 2. Proper washing and sterilization of milking pails and milk cans. 3. Cooling milk by placing cans in tanks of cold water or ice water. L Regular laboratory testing of milk for bacteria, and payment l>ased on the laboratory tests. Pasteurized milk. Dangerous milk can be made safe by heating to (JO^ for twenty minutes, and this does not seriously injure its nutritional value. This treatment kills all non-spore-forming disease germs of ^ Kosenau, The Milk Question, p. 73. (Tells how Mr. 8. L. Stewart, New- burgh, New York, produces milk free from bacteria.) 2 Rosenau, Requirements for "Certified Milk," pp. 151-160. ^ Russell and Hastings, Experimental Dairy Bacteriology, p. 122. * North, "The Dairyman versus the Dairy," American Journal of Publk Health, Vol. V, pp. 510^525. CONTKOL OF BACTERIAL DISEASES 245 Bactehial Tests of Milk produced in Keltox Dairies (Bacteria per Cubic Centimeter) Bv Keltox Dairymen Bv Oxford Dairymen April 5: April 6 : 1,830,000 3,300 1,520,000 3,100 4,830,000 4,600 4,000,000 7,000 1,450,000 4,100 3,600,000 61,0003 60,0001 800 9,0002 2,600 70,000 1,600 500,000 5,600 tuberculosis, typhoid, dysentery, diphtheria, tonsillitis, cholera, and the virus of scarlet fever. This does not make the milk any cleaner, nor does it kill the more resistant bacteria, but if it is dangerous, it renders it safe. Flies, vermin, house pets as transmitters of contact in- fections. After the human hand coine other active g'erm carriers, and among tliese the house fly probably stands first not only in transmitting germs of filth and disease to foods but in combining air-carriage with contact. This prob- lem has been treated in a previous chapter. Roaches and rats and mice should be universally recognized as too filthy to eat with, and should be completely exterminated, along with the flies, from every household. Cats, on account of their often intimate contact with children, have been responsible for innumerable infections, especially of diphtheria. Since this germ attacks cats virulently, they assume the double role of irresponsible patients and mechanical carriers in the family. 1 This dairy, on April 3, had a count of 8,000,000. 2 This count was made March 30. ^ Due to Keltou dairymen raising dust by sweeping at milking time. 246 CIVIC BIOLOGY Every case of '^ cold " or " sore throat " in a cat should be considered diphtheretic or tubercular until proved otherwise. Serious epidemics of diphtheria have been traced to cats, and these have had to be killed or rigidly excluded from homes before spread of the disease could be stopped. Cases of scar- let fever are sometimes traced to cats as passive carriers.^ While dogs may act as mechanical carriers of bacteria, and are responsible for harboring several animal parasites, which we shall have to consider later, they are almost immune from bacterial attack. Recent civic advances due to acceptance of contact infection. Public drinking-cups and common towels have vanished as if by magic. Sanitary regulation of dishwashing and bed linen in hotels and restaurants, sanitary protection of drinking- straws and cleansing of glasses in soda fountains, wrapping and boxing of bread, other foods, and candies, to prevent contact in handling, liquid and individual soaps, and many other items of modern improvement are active steps in the direction of rational prevention of contact infections. As with the dairies, when we all realize that intelligence in per- sonnel is of more importance than equipment, we shall see to it that only the healthy and cleanly and those who know are allowed to work in dairies or take care of foods in markets or eating houses. No man who does not know better than to put his bare hand over a milk bottle, or woman who does not know better than to take candy from a tray with her bare fingers, has any right to serve the public. Our mil- lions of preventable infections and our more than 500,000 deaths annually are the measure of our need in this direction. Resistance, susceptibility, and immunity. Possibly every American chestnut tree on the continent is susceptible — 1 Caroline A. Osborne, M.D., ''The Cat a Neglected Factor in Sanitary- Science," Pedagogical Seminary, 1907 ; also "The Cat and the Transmission of Disease," Medical Recorder, Chicago, 1912. CONTROL OF BACTERIAL DISEASES 247 unable to offer resistance — to the fungus of bark disease. In that case, unless some specimens can be taken beyond reach of the spores, every chestnut tree in America will be killed. If immune trees can be found, it may be possible to propa- gate from them a strain of immune trees and so save the species to the continent. It is possible, though not probable, that something may be discovered which, injected into the sap of the tree or fed into the tree from the soil, will enable it to resist the fungus, that is, give the tree an artificial or acquired immunity. It is conceivable that we might inject some of the sap from an immune tree into a susceptible tree — vacci- nate, or inoculate — and so immunize it and save its life. Every animal or plant offers some resistance to being eaten alive by a parasite. Tins resistance may be natural or ac- quired ; it may be mechanical (skin, bark, cuticle, too resist- ant for parasites to break through) or, as is more common, it may be chemical (some poisonous, toxic substance is pro- duced that weakens or kills parasites). As a nation stung by foreign attack begins to make ammunition, so cells of the host may be stimulated by the toxins of a parasite to produce defensive substances — antitoxins or antibodies. In this case the acquired resistance, or immunity, is said to be active. If the defensive substance, antitoxin, is injected from some other person or animal, as if a foreign nation sent in its army and ammunition, the immunity conferred is said to be pas- sive, and this is not likely to last so long as active immunity. Recovery from certain diseases (whooping cough, measles, mumps, scarlet fever, smallpox) generally leaves the body armed with acquired immunity against a second attack by the same germs — that is, leaves an experienced army that can prevent another invasion. This, in a true sense, is the case, the white blood corpuscles (phagocytes) often gaining the power to eat the germs, probably alive, instead of being eaten by them. The process is not always as simple as this. 248 CIVIC BIOLOGY The white corpuscles may not be able to ingest some bac- teria unless there are certain substances in the blood to help them. These are called opsonins (Gr. oyjrcoveQ), I prepare food for), and their amount in the blood as compared with a nor- mal standard is known as the opsonic index. The injection of killed bacteria of the exact kind that are causing the trouble (made with cultures taken from the patient — autogenous bacterins) often results in a sharp rise in the opsonic index and with this a quick defeat of the invadmg germs. Great prejudice has existed against the use of these vac- cines, antitoxins, bacterins, and serums, and one accident attributed to them, perhaps falsely, is often made to out- weigh in popular prejudice the literally thousands of deaths caused by the natural course of infections. Beginning with vaccination, discovered by Jenner, in 1796, we now have safe and effective vaccines, antitoxins, bacterins, and serums for rabies, diphtheria, tetanus (lockjaw), pneumonia, boils, pimples, and inflammatory fevers, cholera, bubonic plague, bacterial dysentery, cerebrospinal meningitis, and typhoid fever, and, among animal diseases, anthrax, distemper of dogs, hog and fowl choleras, blackleg, and tetanus, with many more that are on the way toward perfection. It is claimed by some high in authority that the present great war will result in lengthening the average of human life by as much as fifteen years, by breaking down apathy and ancient prejudice and demonstrating the value of modern bacterio- logical science. Typhoid has been banished from our army by preventive inoculation. Let some pupil volunteer to look up the story of this and report to the class. Asepsis, antisepsis, germicides, and paths of entrance to the body. Blood wells from a wound, carrying out the germs that may have entered, rendering it germ-free, or aseptic, and then it clots to seal it over. This is nature's primitive aseptic surgery. The saliva is somewhat antiseptic, and the acid CONTROL OF BACTERIAL DISEASES 249 gastric juice of the stomach is strongly germicidal, these bemg nature's provisions for turning the food over to the absorp- tive organs germ-free. Breaks in the skin and mucous mem- branes and the mouth are the great channels of entrance for germs, and the fact that there are so many preventable in- fections proves, that under modern conditions of life nature's provisions need constant reenforcement. In normal breathing through the nostrils the germs are caught before they reach the lungs, so that even pulmonary tuberculosis is coming more and more to be considered a mouth infection, reaching the lungs either by way of inflamed tonsils or by way of stomach, intestine, thoracic duct, and circulation. When the role of bacteria in causing disease was first dis- covered, chemical poisons were sought which might kill the germs without quite killing the patient. Carbolic acid (phe- nol), mercuric chloride (corrosive sublimate), and formalin were the germicides first used most extensively, and the gov- ernment standard of efficiency, " the phenol coefficient," is the germ-killing power of phenol. Later came the delicate, specific, exact antitoxins and resistance serums that kill the particular germ and have no poisonous action on the cells of the body. Other nonpoisonous germicides, especially the hypochlorites, from general use in purification of drinking water and sewage, are being adapted to dairy, home, and personal use. Here oxygen is the active germicide, and the end products of the reaction are harmless calcium chloride in case of hypochlorite of lime, and, with sodium hypo- chlorite, sodium chloride, or common salt.^ 1 " Three grains of a practically harmless substance will kill the myriads of germs in a barrel of water. To do the same work with the poisonous cor- rosive sublimate would require at least one ounce, or of the equally poison- ous carbolic acid five pounds (p. 23). . . . Hypochlorous acid is one of the most powerful oxidizing agents known to chemists. The 'acid mixture' will, within a minute, kill spores which resist 5 per cent solution of carbolic acid for weeks" (p. 54). — Hooker, Chloride of Lime in Sanitation, 1013 250 CIVIC BIOLOGY Keeping abreast of discovery. Bacteriology is a young science, and hundreds of students are pushing discovery forward so rapidly that we must " step lively " to keep up. Have committees of the class invite members of the state and local boards of health and public-spirited physicians to come in and discuss their problems. Try to gain clear ideas of just those problems in dealing with which the community most needs to develop " cooperative good will," and make a test of what a biology class can do to help. No matter where it is, or how large or how small it may be, any com- munity that can, by intelligent, united effort, demonstrate accomplished control of such infections as tuberculosis, grippe, common colds, pneumonia, diphtheria, typhoid, and summer choleras of infants, may "go to the head"; and the class of young men and women who help to attain this result will have a story to tell that the sick and tired old world has waited thousands of years to hear. Problem summary. What do we mean by " clean hands " ? Are our fingers generally clean enough to put into our own mouths or into the mouths of other people, that is, to handle our own food with and that of others ? Tests : Touch finger tips, unwashed and washed, to agar plates, incubate, and compare growths. To determine how many germs we may collect on the hands in a half-day's work, wash the hands with- out soap (cleaning the nails thoroughly) in two liters of sterile water. Inoculate a plate with 1 cubic centimeter, incubate, count colonies, and estimate total number. — Read " Dirty Hands and Typhoid Fever," American Journal of Public Health, Vol. IV (1914), p. 141. Study conditions in local stores, bakeries, and candy shops. Are foods and confections that go directly into the mouth handled with the bare hands? Can you devise practical ways and means of doing away with all such handling? Look up thoroughly hygiene of mouth, throat, and nose, and adopt a definite plan that shall insure perfectly sound teeth, uninfected tonsils or nares, and absence of adenoids. Arrange a campaign to see that ordinances against spitting in public places are obeyed. Report infractions to board of health. CONTROL OF BACTERIAL DISEASES 251 Let each member of the class work out one of the following problems in detail and present results to class : IIow would you plan to take sole care of a case of typhoid (to insure against catching it yourself or permitting it to spread to others) ? of tuberculosis ? of grippe ? of pneumonia? of diphtheria? of dysentery? of erysipelas? of leprosy? of scarlet fever? of measles? of pellagra? of smallpox? (Refer to best available manuals for trained nurses.) What precautions would you take if you were a typhoid carrier? if you were a diphtheria carrier? if you were infected with tubercu- losis? if you had the grippe? if you had tonsillitis? if you had a cold? Is the Schick reaction used in your district to test immunity to diph- theria? Look up use of Widal reaction in detection of typhoid carriers. Make out a complete list of diseases of man and other animals for which we have reliable antitoxins, vaccines, or bacterins. Discuss their use in your district and get reports from those who have tested them. File this list in the laboratory and note changes and growth from year to year. It is estimated that in 1914 diseases of farm animals caused damage to the amount of $212,000,000. Can the class work out plans of co6i> eration by which any of these diseases may be brought under control ? Compare the merits, for various purposes, of different disinfectants, antiseptics, and germicides on the market. Study especially the home and dairy use of the hypochlorites. Get the reports on all these things from the United States Public Health Service, Washington, D.C. Collect and discuss national, state, and local quarantine and health laws and ordinances. Visit as many of the local dairies as possible. Obtain the official score cards from your dairy inspector and study the scoring he has given. Are the dairymen included in the scoring? In the light of all you have learned about bacteria, discuss the prob- lem of washing dishes properly. Should we banish the " common dish- towel " along with the "common roller towel." Make plate tests for numbers of bacteria in " dishcloths," in " dish-towels," in " dishwater," and on the dishes after different methods of washing and drying. How do these tests compare with thoee made on dishes after actually boiling for five minutes in the rinsing water ? after treating with hypochlorite in rinsing water, without wiping ? It is being claimed that spread of infections in families, especially of colds, grippe, and tonsillitis, might be greatly reduced by steriliza- tion of dishes. Can the class find a test for this in their own homes ? $ T3 ^ 5 O ^•^ w i '^ aj cc o robably eight to twelve months." This is a sectional problem, and every school (especially every high school) in the South should have in its school library the latest information olv tainable from the Rockefeller Sanitary Commission for the Eradication of Hookworm Disease,^ and also the bulletins of the United States Bureau of Public Education, notably Bulletin, No. 20, " The Rural School and Hookworm Disease," Washington, D.C., 1914. Knowledge is growing so fast that the latest and best should be secured from year to year. Fig. 120. Trichina worm embryo cysts in luiman muscle and adult female from iutestinal wall After Leuckart ^ Address, Washiufjton, D.C. CONTROL OF ANIMAL PARASITES 269 While the study of these parasites of disease may seem disagreeable at first, where can we find keener inspiration than in the thought of their control by human cooperation Fk.. I2l, C;1h.>.s with state inspector ; iiic iii cold storage and intelligence ? By this road only can mankind free itself from these time-old and world-wide tormentors and sappers of human life. So may even the parasites of the Pharaohs help to teach us lessons in cooperative good will. 270 CHAPTER XXV CIVIC PROBLEMS RELATING TO MOLLUSKS It is doubtful whether there is any farming land in the United States which yields as great a profit to the acre as the bottoms which are used for oyster-planting in Rhode Island. — W. K. Brooks, ''The Oyster," p. 135 The sea mussel {Mytilus edulis) is one of the most important food re- sources of the ocean, and as yet France, Belgium, and Holland are the only nations that appreciate its real food value, No shellfish grows so rapidly and abundantly. Natural beds often contain as many as 8000 bushels to the acre, and planted beds yield at the end of three years from 4000 to 6000 bushels per acre. At present prices this means from |1600 to |2400 per acre every three years. The high nutritive value and low cost of sea mussels make them the most economical shellfish on the market. The same money will buy four times as much food in mussels as if spent for long clams, and ten and twenty times as much as if invested in oysters and lobsters respectively. They are also most palatable and easily digested. As these facts come to be better under- stood it is hoped that the American people will no longer neglect this vast source of food supply, but convert it into the wealth of the nation. — Irving A. Field Possibilities of marine food supply. '' Four feet square of the ocean is capable of producing food enough to support a human being." ^ This statement, made in a public lecture by an eminent authority, may seem incredible, but it may also serve to indicate that we have scarcely begun to realize the wealth of life in the waters. Of the 518,900 species of animals known, 61,000 are mollusks, almost all aquatic. In regard to how many of these do we know anything? Oriental peoples utilize a considerable number of them, and Europeans, since remote antiquity, have feasted upon deli- cious mollusks, common but unknown to us. 1 Statement by Major McGee in an address at the University of Wis- consin, 1892. 271 272 CIVIC BIOLOGY Sea mussels. These most abundant mollusks of our coasts might supply the soup and fish courses for every dimier in North America without strain upon their reproductive pos- sibiKties. How many have ever heard of them ? How many have tasted them in prime condition, or even at all ? Some may have heard from irresponsible sources that sea mussels are poisonous. So are oysters or clams that are taken from sewage-polluted waters or that are dead and half decayed; and stale lobsters, crabs, chicken, veal, and even milk may be poisonous. '' Mussels taken from pure water which has free circulation have never been known to produce injurious ef- fects. A New York dealer who has been selling mussels for years has never known of a case of poisoning from them. Neveithe- less, too much emphasis cannot be laid on the fact that care nmst be exercised in choosing proper localities for the culti- vation and collection of mussels for market. They must be sold to the consumer m a perfectly fresh condition or serious results will be likely to follow.'* ^ It would be an interesting problem for any community unit to figure out its aquatic resources and possibilities, ana- lyze the different elements, and estimate the percentage of present utilization. For the United States as a whole this is roughly attempted in the following table. 1 Irving A. Field, "Food Value of Sea Mussels," Bulletin No. 743 of the United States Bureau of Fisheries, 1911, p. 125. Fig. 123. Cleaning sea nnissels commercially Photograph by I. A. Field CIVIC PKOBLEMS DELATING TO MOLLUSKS 273 Amount AND Value OF Mollusc AN Products in the United States^ Clams, bard Clams, soft Clams, razor Clams, surf Sea mussels Fresh-water mussel Abalones, shells Abalones, meat . Cockles, conchs. Oysters, Atlantic (Jysters, Pacific . Oyster shells . . All other shells . Squids .... Scallops .... Present Possible j Yield, pounds Valvie I Yield, pounds 7,805,000, ^1.317,000 8,654,000 553,000 259,000 265,000 8,542,000 81,869,000 1,005,000 146,000 231,146,000 2.163,100 25,000 21,000 12,000 (592,000 16,000 35,000 15,020,200 693.500 952,000 1 8,400 2,562,000 j 43,000 2,432,000 317,000 Value i|35,000^ 15,000^0 3 The most instructive factor in such problems is hkely to be the causes that work to depress actual below possible resources. Here we shall find ignorance of values, lack of knowledge as to life history of forms and hence of practical means for development, and, above all, in any development of aquatic resources, the old, uncivic spirit of piracy, handed down from the times of natural oyster beds, which still holds that anything whatsoever under water belongs to the one who can get it. '' Oh yes, this is a fine location for oysters, and I did go to considerable expense and planted a lot, but ^ Statistics furnished by the United States Bureau of Fisheries for 1908. At present the Bureau cannot supply any estimates of possible yields. Fill out the table and keep it up to date as figures become available. Make a similar table of actual and possible yields for local waters. ^ T)r. Field's estimate of value of sea mussels produced in 1915. ^ Dr. Field's estimate of possible value of sea mussels produced in any one vear. 274 CIVIC BIOLOGY I never got an oyster. As soon as they grew to amount to anything the oyster pirates came along and cleaned them up in a night. So I had to give it up." ^ Classification. Our common mollusks may be classified into three main groups : 1. Lamellibranchs (lamella-gilled) : Clams, mussels, oysters, scallops, — bivalves, — all are aquatic (marine and fresh-water). All the great food mollusks belong in this class, because their gills enable them to filter out and feed upon the inexhaustible supply of algae and other organisms floating in the water. 2. Gastropods (stomach-footed) : Snails, conchs, periwinkles, aba- lones, — typically coiled univalve shells, — and many shell-less forms (garden slugs) are marine, fresh-water, and terrestrial. Most gastropods are carnivorous, but a number are vegetarian, like the edible snails, the slugs, and the periwinkles and abalones, which feed upon the algae and seaweeds of the bottom. 3. Cephalopods (head-footed) : Squids, cuttlefishes, devilfishes, octo- puses, nautilus, are all marine, the molluscan over- (or under-) lords of the ocean. The cephalopods are all carnivorous, and many of them are used for food by oriental peoples. Our common squids, used now for fish bait, are good food mollusks. Typical problems and life histories. While schools along the seacoasts have the advantage, the mollusks of our rivers, lakes, and ponds, and even of our woods and gardens, offer problems of no mean interest. Oysters. Osirea virginica is the native oyster of the Atlantic coast from Cape Cod to the Gulf of Mexico. It has the reputation of being the finest edible oyster in the world. A small, starveling variety, the " coon oyster," forms extensive natural beds throughout the salt-marsh sedges and mangrove swamps of the Southern states. A small but delicious species, 0. lurida, is native to the American Pacific, and young 0. virginica, since 1870, have been shipped across the continent to grow and fatten in the favored coves of the Pacific coast. Almost the entire Pacific coast line, however, from Puget Sound to Mexico, is a waste of desert sand, unindented and open to the ocean front, with line after line of huge beach combers out as far as the eye can reach — terrific instead of " pacific," and not at all suited to the oyster. The United States Bureau of Fisheries has made repeated experiments in colonizing Atlantic oysters in favored places along the Pacific, but, 1 Experience of a shore owner on the Chesapeake. CIVIC PKOBLEMS KELATING TO MOLLUSKS 275 while they evidently find food and conditions generally favorable to growth, there has been difficulty in getting them to spawn. It is claimed that they have now become acclimated and are spawning freely in some of the inlets of the Washing"ton coast. If this is true, such oysters ought to be used exclusively for seeding all available coves of the Pacific coast, which are few at best. To use them otherwise, until this is done, would be monumental folly. Pacific-coast schools should give special attention to this problem. Ofttrea edidis is the native oyster of the European Atlantic, and, like O. lurida^ is hermaphroditic, while 0. virginica is bisexual. For a com- munity interested in oyster culture a good topic would be a comparison Fig. 124. Ostrea virginica Left, old shell covered with young oystei-s ; middle, shells of four large specimens about 6 inches long ; right, sliell of an old oyster riddled by boring sponges of local with European methods. Possibly France has attained nearest to 100 per cent efficiency in the use of her available oyster beds. The French attend not only to the rearing of the oysters but to the propa- gation of certain kinds of algae which impart desired colors and flavors to the finished product. The civic problem which must be solved by the rising generation is that of developing the oyster industry to as near 100 per cent efficiency as possible. Much as we have already done in this direction, probably not more than 2 per cent of the possible j)roduction of American waters has been attained. How we can develop to 100 per cent efficiency in each community is the problem for each community to solve. Sea mussels — Mytilus edulis (and other species). The range of Mytilus is circimipolar, fringing the northern coasts from Japan around to the 276 CIVIC BIOLOGY Mediterranean and from North Carolina around through the Arctic Ocean to San Francisco. In depth it ranges from halfway between tide marks to probably 100 fathoms. Under most favorable conditions, in American waters, the mussels may grow to an average length of from 2 to 3 inches in a year. In England, by the bed system of cultivation, they require two and generally three years to attain a length of 2 inches; but in France this size is secured, by the huchot method, in a year and a half. A female mussel has been observed to lay 12,000,000 eggs in fifteen minutes, almost the entire substance of the animal, except the heart and gills, being transformed into eggs or sperm, which are thus quickly shed once a year. The spawning season varies with lati- tude and with the temperature of local waters, extending from Feb- ruary to September; and since the mussels are in prime condition when full of reprodiu^tive products, the beginning of the spawning season should be determined for each typical bed in a locality, to the end that the yearly crop may be harvested at the right time, that is. Just before spawning occurs. Thus mussels may ha made to fill the gap in the markets from May to August, when oysters are out of season ; and, in fact, according" to the extended investigations of Dr. Field, sea mussels luay be found in fair or prime condition every mouth in the year. Of course, as long as no one knows how good they are, this vast food supply will continue to go to waste. As a matter of practical biology; then, why not arrange for a course of mussels in class banquets or other entertainments, and agree to call for them frequently in local restaurants and hotels. When once mussels have been tried, the de- mand for them, and consequently the supply, will grow until the whole country is benefitebarbed hooks, which catch into the skin of the fish when they are snapped together. The 282 CIVIC BIOLOGY species that do not have hooks are taken in with the breathing currents of fishes and clamp on to the gill filaments. The tissues of the fish grow over the glochidia, and within the sac thus formed they grow and change into the adult form. Finally, at the end of from two to ten weeks, according to their species and the temperature of the water, they kick themselves out of these cysts and begin their free life on the bottom. So far as we know, this is the only way a young fresh-water mussel can be carried over this criti- cal stage from glochidium to adult, and this means that extermination of fishes must result in extermina- tion of mussels as well. Problems. Ascertain from the nearest markets which species of mussels produce the most valuable shells, and make a collection of these for the school museum. Examine specimens of valuable species and make a table showing the months when the gills contain glochidia. Discuss the advisability of a closed season including these months. Estimate the number of glochidia per adult mussel. Examine all fishes caught for glochidia in gills or fins and skin. How many may a fish carry? Try, possibly with the help of the state fish commission or the United States Bureau of Fisheries, to make a plan for the best possible utilization of streams, ponds, and lakes in the locality, for both mussel and fish culture. Gastropods. Comparatively slight civic values attach to this group. The abalones are of interest in California, and the periwinkle (Littorina), brought to the Atlantic coast from Europe, where it is used for food, has become abundant from New England southward. It is also of value in cleaning oyster beds of seaweeds. A number of other marine forms, the oyster drill (^Urosalpinx), Fulgur, and Natica, feed upon oysters and clams. Fig, 129. Garden slugs spinnin< mucous threads Photograph by the author CIVIC PROBLEMS RELATING TO MOLLUSKS 283 The edible snail {Helix pomatia) is imported from Eurojie and is raised in specially fenced gardens and fattened for market. This may Fig. 130. A common land snail be studied as an interesting novelty in most American communities. For all we know, may not our big, fat garden slugs be food delicacies ? Compare garden slugs with marine or fresh-water snails, which they may be seen to resemble, except in respect to the rudimentary shell. These slugs are often as destructive in gardens as any in- sect, and, being nocturnal, are little known. Collect the eggs (translucent, yellowish, about the size of buckshot, in masses of thirty or more, found in damp places under boards) and keep them in a glass jar or aquarium to watch their development. If the life history of these pests were better known, we might control them more effec- tively about our gardens and greenhouses. In connection with other field work, make a collection of common marine, fresh-water, and terrestrial gastropods. Keep them in suitable aquaria or vivaria, to study habits and foods. Note that some snails are " left-handed " and most are " right-handed." (If held with opening up and spire pointing away from you, the dextral shells have the opening to the right, the sinistral, to the left.) The commonest and most interesting are the pond snails, belonging to the genus Physa, which can be readily distinguished by their sinistral Fig. 131. Common snails, sinistral and dextral 284 CIVIC BIOLOGY shells. If kept in a balanced aquarium, Physa will serve to demonstrate most of the interesting reactions — locomotion, spinning mucous threads, feeding, breathing, egg-laying — of this group of moUusks. The eggs will be laid in transparent masses of jelly on the glass, and will thus afford opportunity to obsei-ve the embryological development of a gastropod. Tyrian purple, the dye, was obtained from marine gastropods, which have been known as purpuras since remote antiquity. Cephalopods. No more interesting- specimens for the marine aquarium can be had than the young of our common squids, with tlieir flashing changes of color, their hiding, ink-cloud maneuvers (equaled only by the most astute politi- cians), and their lightning-like efficiency in catching fish nearly as large as themselves. It is almost impossible to believe that these keen, active, intelligent creatures are really mollusks. The cephalopods furnish bait for our cod fisheries, sepia for artists, and cuttle bone for canaries, and are used extensively for food along the Mediterranean and among oriental peoples. Some of the deep-sea forms reach enormous size ; we hear thrilling stories of their encounters with whales, and they probably furnish whatever basis there may be for sailors' yarns of sea serpents. Fig. 132. Atlantic squid CHAPTER XXVI CRUSTACEA The tislies in a school of mackerel are as numerous as the birds in a flight of wild pigeons. Goode, in his " History of Aquatic Animals," tells of one school of mackerel which was estimated to contain a million barrels, and of another which was a windrow of fish half a mile wide and at least twenty miles long ; but while the pigeons are plant eaters, the mackerel are rapa- cious hunters, pursuing and devouring the herrings, as well as pteropods and pelagic Crustacea. Herring swarm like locusts, and a bank of herring is almost a solid wall. In 1879 three hundred thousand river herring were landed in a single haul of the seine in xVlbemarle Sound ; but the herring are also carnivorous, each one consuming myriads of copepods every day. In spite of this destruction and the ravages of armies of medusse and siphonophores and pteropods, the fertility of the copepods is so great that they are abundant in all parts of the ocean, and they are met with in numbers which exceed our powers of comprehension. On one occasion the Challenger steamed for two days through a dense cloud formed of a single species, and they are found in all latitudes from the Arctic regions to the equator, in ma&ses which discolor the water for miles. We know, too, that they are not restricted to the surface, and that banks of copepods are sometimes a mile thick. When we reflect that thou- sands would find ample room and food in a pint of water, we can form some faint conception of their universal abundance. Modern microscopic research has shown that these simple plants [the algie in the water], and the globigerinae and radiolarians which feed upon them, are so abundant and prolific that they meet all the demands made upon them and supply the food of all the animals of the ocean. This is the fundamental conception of marine biology. The basis of all the life in the modern ocean is to be sought in the microorganisms of the surface. — W. K. Brooks, "Salpa," pp. 146-147 All the ingenious men, and all the scientific men, and all the fanciful men, in the world, with all the old German bogy painters into the bargain, could never invent . . . anything so curious, and so ridiculous, as a lobster. — KiNosLEY, " Water Babies " 285 286 CIVIC BIOLOGY SPECIES TIME ^ UNDER NATURAL CONDITIONS Attack by Man Adults. Lobsterlings -i-^ UNDER HUMAN CONTROL 4=5= [Natur ab Enemies ],-\i.. ^ ^^ Fig. 133. Diagram expressing Brooks's law of the extermination of a species by man as applied to the lobster problem The species is shown flowing along from an indefinite past nnder natural condi- tions, with minor fluctuations, hut maintaining a practically constant population, having adjusted itself to its natural enemies hy developing great fecundity, as seen in the wide stream of eggs and larvae, most of which are taken in the larval stage hy natural enemies. At the large arrow civilized man attacks the slender stream of adult lohsters which nature has selected to keep up the supply of eggs. This strikes the species as a "catastrophe." Man's attack is unlike that of all other enemies. Instincts of self-pi'eservation, thickness of shell, and large size, which made the adult lobsters almost immune from attacks hy other enemies, all ai-e of no avail. Although man takes hut a small numher of adults, the bal- ance is disturbed, fewer eggs are produced, natural enemies crowd and tend to take a larger proportion, and the species swiftly approaches extermination. Even if man ceases his attack when the numbers have become reduced so as to render their further pursuit unprofitable, natural enemies may kill off the stragglers, and before we realize what has happened, the race is extinct. If we did .shut off all the streams of young and adults at the point of the large arrow, we should have a picture of the extermination of the lobster. Under human control, if even a few adult breeders are left, man can increase the number to any desired amount ; he can lift the eggs and young above the reach of natural enemies, or crowd them down, or both, and .so increase the .species to the limits of room or of food supply. This is what we hope is now being done, and we shall watch the future curves of increase in the expectation that the price of lobsters may begin to decline toward reasonable limits. This diagram is applicable to any species ex- terminated or in danger of extermination by man — passenger pigeon, dodo, great auk, and many other species now lost to the world 286 CRUSTACEA 287 General. Crustacean problems parallel those of the mol- lusca. Lobsters, crabs, shrimps, and crawfish are valuable for food. Some of the most higlily prized species require to be pro- tected by law, and we are beginning to work out methods for their artificial propagation. Some of the terrestrial crawfish are locally injurious to vegetation. There is this difference: crabs and lobsters move about more freely than clams and oysters, and hence are not so well suited to stable aquicul- ture. On this account the United States Bureau of Fisheries, and the fish commissions of the states concerned, must assume responsibility for keeping up the supply by propagation, since this cannot be done with profit by private individuals. Economic value. The table below presents the chief eco- nomic Crustacea, and its most suggestive feature is likely to be the wide difference between actual and possible utilization of these resources. Crustacean Products OF THE United States in 1908 Actual Value Possible Value » Lobsters ... 11,931,000 912,000 494,000 127,000 32,000 Blue crabs Shrimps prawns Pacific crabs Crawfish Classification. The Crustacea are divided into two main groups, the Entomostraca (mostly microscopic or small, includ- ing the ostracods, copepods, and barnacles) and the Malacos- traca (the lobsters, crawfish, shrimps, prawns, and crabs). Entomostraca. Although inconspicuous and little known, these minute Crustacea are of the greatest biological signifi- cance. If we had them all gathered into a ball, and all the rest of the animal matter of the world rolled into another 1 Estimates not obtainable. 288 CIVIC BIOLOGY ball, it is quite possible that the Entomostraca would be the heavier of the two.^ They form the main food of the young of fishes and many other aquatic animals, and also of the adult fishes that are provided with gill rakers — the herrings, smelts, shad, and others. They are thus the connecting link between the vast store of floating, microscopical plants and animals (the primitive food supply) and all higher life in the water. Baphnia and Cyclops are examples that may be found in almost any fresh-water aquarium or in streams, ponds, and pools everywhere. The fairy shrimp (^Branchipus) is also found in the icy pools of early spring. The Lobster (Homarus americanus). Of the invertebrates used for food the lobster ranks next in importance to the oyster, and of all marine animals, for the past thirty years, it has been m the greatest danger from overfishing. The reason for this is seen in the following table, the supply having been drained to the utmost on account of soaring prices. New ExiiLANi) Lohstki: Fishehv Ye All Pounds Value Price per Pound 1880 19,836,233 30,449,603 15,567,081 14,734,000 11,504,257 $473,341 833,746 1,362,962 1,855,000 2,254,486 10.024 0.027 1890 1900 0.088 1908 0.125 1913 ... 0.196 1 The writer has thought, as he steamed through a veritable slush of copepods that colored the ocean for hundreds if not thousands of miles, that here must be the greatest of all untapped and unthought-of sources of supply of animal matter. If the ship's engines could be geared to some effi- cient filtering machine, a cargo could be secured as fast as hoisting and stor- ing machinery could handle it. The material might prove as good, or better, than lobster for salads (but the microscopic spines and bristles would be likely to interfere with human edibility). It might prove of value for poultry and swine, for oil production, and, at any rate, for fertilizer. Perhaps it would solve the problem of food in fish hatcheries, especially for marine species, and make possible the rearing of young lobsters in any quantity. CRUSTACEA 289 Range. The American lobster ranges along the Atlantic seaboard from Labrador to North Carolina. Possibly no ven- ture in the field of marine aqniculture would prove of greater economic value than the introduction of this species into the Pacific ; but although egg-bearing lobsters have been shipped across the continent by thousands and in carload lots, up to this time all attempts of the United States Bureau of Fish- eries to colonize the Pacific have failed. While hiding among the crevices of rocks would seem to suit the habit of the lobster best, it apparently thrives as well on sandy and even muddy bottoms, and it ranges from the tide pools to water 100 fathoms, or even more, in depth.^ Size, growth, and life history. Female lobsters spawn once in two years; the eggs as laid are cemented to the swimmerets underneath the abdomen, and here they are carried during \he long incubation period from July or August of one year till May or July of the next. The hatchlings — delicate, transparent creatures about one third of an inch in length — swim feebly, or rather "tread water," and so tend to rise toward the surface. They feed voraciously upon copepods and diatoms that they find floating in the water, and they eat one another whenever they can — a vicious habit which is one of the chief difficulties in rear- ing them artificially. They swim thus for two or three w^eeks, growing and molting three times in the interval, all this time at the mercy of every tide, wave, and current and of every open mouth they may encounter. This is the critical period in the lobster's life, and probably not one in ten thousand, under natural conditions, survives its accidents and dangers. At the third molt the young assumes adult form, and the tiny lob- sterling tends to seek the bottom and may even begin to burrow for greater protection. It is now a little over half an inch in length, still a helpless morsel for every sharp-eyed minnow. When it is about twenty- five days old, the fourth molt brings the lobsterling to the fifth stage, 1 Barnes, Methods of Protecting and Propagating the Lobster, E. L. Freeman Co., Providence, Rhode Island, 1911. Refer to this for further data on the habits and natural history of the lobster. Also, if. undertaking special work on this problem, write to Experiment Station, Wickford, Rhode Island, for up-to-date information. 290 CIVIC BIOLOGY when the bottom habit is more strongly fixed. It is comparatively easy to hatch lobster eggs, but if the fry are liberated as soon as hatched, nothing is gained over natural hatching. For about thirty years ex- periments have been in progress in this country to discover methods of rearing lobster fry through the critical free-swimming stages to the fourth, or bottom, stage. For years results were negligible, but at last, Fig. 134. Berried lobsters, taken from pound at Boothbay Harbor (Maine), in course of transfer to wells of the steamer which is to convey them to the hatchery for stripping United States Bureau of Fisheries in 1910, by holding them in floating cars the Wickford station was able to score a record of 8946 fourth-stage lobsterlings from a counted lot of 10,000 newly hatched fry. The best European result at that date was 6.6 per cent, beginning with 1500 in the second stage. By the end of its first year the young lobster has reached the length of 2^ inches, and not until its sixth year does it attain the respectable market length of 10 inches. In the usual effort to save the lobster industry and the species, laws have been passed by the states most concerned; but these have not been effectual, on account of lack of knowledge, and those of different states still conflict seriously. Study CRUSTACEA 291 the lobster law in your own state and in neighboring states and discuss practical improvements.^ Probably no one has ever seen a lobster known to be dead of old age. While specimens over 15 inches long and weighing more than 2 or 3 pounds are now rare in the markets, specimens 2 feet in length and weighing 10 pounds were not rare some years ago. The largest lobster on record was caught off the Xew Jersey coast in 1897. From end of chelae to tip of tail it measured 42 inches, and it weighed 34 pounds. Growth has been followed up to the thirty-third year, at which time the lobster is almost 2 feet long. If a lobster lives forty years and produces twenty batches of eggs, averaging 100,000 each, an adult pair would produce 2,000,000 eggs. This would mean, with the species holding its own in the struggle for existence, that under natural conditions only one egg in a million grows to become adult. If man kills the one that nature has preserved out of the million to keep up the species, eggs and young will fail and the lobster will become extinct. Our laws are based on the totally inadequate assumption of the fisher- men that if a lobster is spared until it grows to be 10 inches long and lays only one batch of eggs — about 10,000 — the population of the species will be maintained. Both theory and experience prove the fallacy of this idea. Brooks's law. We must work out a biologically correct solution of this problem or lose our lobsters. Dr. W. K. Brooks ^ has given a dis- cussion of the problem as applied to marine fishes. This might well be 1 Rhode Island has led the way by making a closed season, from Novem- ber 15 to April 15. All the states except New York fine from $5 to $100 for killing an egg lobster, but the eggs are easily brushed off. Short-lobster laws differ. In Maine a lobster must measure 4f inches, body length (equal to 10^ inches long) ; in New Hampshire, 10| inches ; in Massachusetts, 9 inches ; in Rhode Island, 4i inches, body measure ; and in New York, 9 inches. According to the biologically correct view of Dr. Field, of the Massachusetts Fisheries and Game Commission, all these short-lobster laws protect the wrong end of the animal's life. A lobster 10 inches long produces 10,000 eggs ; one 12 inches long, 20,000 ; a 16-inch lobster, 100,000. The old lob- ster is thus ten times as valuable to the species for egg production, and, being coarser and tougher, may not be as valuable for food as the legal- limit lobster. According to Field, lobster pots should be made with open- ings too small for the large lobsters to enter, S\ or 3^ inches in diameter, and with slats open enough to permit all lobsters under a certain size to escape. '-^Brooks, "The Artificial Propagation of Sea Fishes," Popular Science Monthly, Vol. XXXV (1889), pp. 359-367. 292 CIVIC BIOLOGY called " Brooks's Law of Exterminatiou of Sixjcies by Mau." Stated in his own words, this law is " To marine food fishes man is a catastrophe. not a natural enemy." This means idult period, 40(/) y years; 2 individ- uals, one pair II 1 Lobsterling period, \6 years; 200 — >> 2 individuals lAtrvul {critical) period, 1 month ; 2,000,000 — y 200 individuals Fig. 135. Diagram representing the indi- viduals at different stages in a generation of lobsters This is another form of expression of Brooks' s law. The typical form is a pyramid, with a broad base of eggs and young maintained by a small apex of adults. Each species of animal or plant has a form of its own de- pending on number of eggs and duration of the different stages. The large number of eggs, the long life of the adults, and the extreme reduction of nmnbers in the short critical, larval stage reduces the typical pyramid in the case of the lobster to a monument with a broad base of eggs which shrinks suddenlj'^ during the larval stage to a slender spii-e representing the adults Man takes the adults which natural enemies have spared to con- tinue the species." Figs. 138 and 135 show this lawdiagram- matically as it applies to the lobster. It is applicable t^ every species that man attacks, from oysters and lobsters to whales and pine trees. When man disturbs the nice balance of nature he must assume control (" have dominion ") or lose the species. Blue crab — Cattinectes sapi- dus. This common crab of the Atlantic<'oast nuirkets ranges from Massachusetts Bay to Mexico, and, while it is taken by millions every year, shows as yet no alarming signs of decrease. Two facts in the natural history of the species may largely account for this : the eggs are minute, a female laying on the average more than 3,000,000 at a batch ; and, while molting, each female is protected by a hard-shelled male. Pacific crab — Cancer magister. This robust crab, 7-9 inches broad by 4-5 inches long, ranges from Alaska to Lower California. In the markets of the Pacific it supplies the place of both the lobster and the blue crab of the Atlantic. State laws are beginning to CKUSTACEA 293 protect these crabs by making closed eeasous and by specifying size limits, but the natural history of this species has not been adequately studied. Crawfish — Astacus (Pacific); Cambarus (Atlantic). Many species of these two genera inhabit North American fresh waters and lowlands, several of them growing to 6 inches in length. They are extensively used for food in P^urope and are growing in favor in some parts of this country. The flesh is delicate and sweet, like that of lobsters and crabs, and there is no good reason why they should not be much more widely Fir;. bSfi. Female and male crawfish, the female with eggs appreciated and utilized. In the waters they often form the chief food of our game fishes, especially of the black bass. Crawfish are found in the fresh waters of the temperate zones of all the continents except Africa, and it is evident that they have developed from a number of different marine forms. The largest crawfish in the w^orld is Astacopsh frankiimi, found in the small streams along the north and west coasts of Tasmania. These often weigh as much as 9 pounds ; and if they could be safely introduced, they might give us an industry for our fresh waters that would rival lobster cidture. The land crawfishes, known as " chimney builders," dig holes in soft ground, generally down to water. These are about an inch in diameter and are surrounded by a chimney of excavated earth. This burrowing habit makes them serious pests in embankments and levees. They are also, in part, vegetable feeders and are often destructive to young plants of field or garden. A few drops of carbon bisulphide in a burrow^ will 294 CIVIC BIOLOGY kill the occupants. The Biological Survey has designed a special drop- ping can to deliver the proper amount, so that extermination of craw- fish from land is now quickly accomplished with slight labor or expense. Crawfish are also excellent food for poultry. The female crawfish, distinguished from the male by her broader abdomen, carries the eggs attached to her swimmerets, as do the lob- sters and crabs (Fig. 136), the young passing through the nauplius, or free-swimming, stage within the shell. Even after hatching, as tiny crawfish they remain attached to the mother until after the third molt, when they scatter to take care of themselves. One or two pairs, kept in an aquarium or vivarium during the hatching period (March to June), will afford most valuable opportu- nities for observing the instincts and habits of a crustacean. Per- haps some member of the class will volunteer to do this. If so, he must study carefully to make conditions as normal as possible, and must feed well, or they may kill and eat each other, and the females may even devour their own eggs. . CHAPTER XXYII ' PROBLEMS OF FISH AND FISHING You might have the rivers as pure as the crystals of the rock, beautiful in falls, in lakes, and in living pools — so full of fish that you might take them out with your hands. — Kuskix Now what happens if, after each one of the natural enemies has claimed its victims, a new enemy not provided for by Nature suddenly attacks the few adult survivors which Nature has provided to perpetuate the species ? What happens when the last drop falls into the brimming bucket ? What happens when the proverbial last straw is put on the load ? It may be quite true that, for each codfish which man catches, the natural enemies destroy a million. That has no bearing on the subject. Nature has provided for the de- struction of the million. Before their birth they were destined to premature death. The one was reserved by Nature for another purpose. — W. K. Brooks After all that has been said about anglers and angling, two thirds of the line fishing of the world is done by boys. The boy may fish with a fly, but he does not spontaneously take to this method. Fly fishing is an art, a fine art beyond a doubt, but it is an art and, like all art, it is artificial. Fishing with an angleworm is natural. It fits into the need of the occasion. It fits in with the spirit of the boy. . . . The angleworm is perfectly at home on the hook. It is not quite comfortable anywhere else. It crawls about on the sidewalks after a rain, bleached and emaciated. It is never quite at ease even in the ground, but on the hook it rests peacefully, with the apparent feeling that its natural mission is performed. — Holder and Jordan, "Fish Stories," p. 237 Civic problems. Are the waters of your neighborhood stocked with the best fishes (for food and sport) that are suited to them? Are they supplied with such numbers as the lakes, streams, and ponds can reasonably support ? Are the waters clean and clear, unpolluted by the wash of soil not properly held on the farms, where it belongs, by chemical wastes from factories, or by sawdust from lumber mills, so that they remain well adapted to the valuable fishes native to 295 296 CIVIC BIOLOGY them ? Do all the people have all the good hsh and good fishmg they need to keep them good-natured ? There are millions of springs and brooks and flo\ying wells, many of which might be turned to good account in forming liome fish ponds. These might be made to serve as storage reservoirs for irrigation or stock watering, and might be so developed over the country as to help in solving problems Fig. 137. Kxtenninatiiig shad fiom a Virginia river Largest seine in the world, 9600 feet long. The seine was hauled hy steana power and the labor of 80 men. and was drawn twice daily, at ebb tide, throughout the season. As many as 3600 shad were taken at one haul, and 126,000 in one season : 250,000 alewives were caught at one time. The season's yield of shad fell to 300, and the fishing w^as consequently discontinued in 1905, after having been carried on for a century. This seine was a source of eggs for the Bureau's shad hatchery on this river, Stony Point, Virginia. United States Bureau of Fisheries of increasing floods in the river valleys. Waste hollows and ravines might be turned into the most productive areas of our farms, acre for acre, when properly stocked with fish. Has this been adequately worked out for the district?^ 1 Johnson and Stapleton, "Fish Pondf Bureau of Fisheries, Washington, lOlo. Farms.'' Document No. S26, PROBLEMS OF FISH AND FISHING 297 If for any district iii the United States or Canada the above questions can be answered in the affirmative, there remains still one thing for the class in civic biology to do. Write up the story to tell how the community did it. It will prove the most mteresting and instructive ''fish story" ever written. Survey of district. The first step toward a solution of the above problems is a sur- vey of local waters. An interested group, or com- mittee, of the class may subdivide the district among its members, eacli of whom will go over his part and make a map, to scale, of lakes, streams, and ponds, along with available pond sites, springs, and flowing Avells. Indicate stream flow by arrows and depths by contour lines, and adopt some uniform method of showing areas of vegetation and kinds of bottom — rocky, gravelly, sandy, or muddy. While working over the ground in this way, observe and record condition of water. Is it clear or nmddy? Do sources of pollution exist ? How might these be remedied ? (Con- sult state laws in this connecticm.) Record all fishes seen, and gather records, from neighbors and local fishermen and markets, of the numbers and values of the different fishes taken during the past season. This should result in a com- plete list of the fishes of market value, with their relative Fig. 138. Trial fishing on the Albatross Experimental catch of cod and hahbut taken in twenty minutes by the Albatross while ex- ploring? a new bank oif the coast of Alaska. United States Bureau of Fisheries 298 CIVIC BIOLOGY importance, and from these data we should be able to con- struct a table showing the crop of each kind of fish for the entire district. We may then figure per acre production and percentage of effective utilization of each water unit.^ In making the survey, seek to arouse the interest of the community. Ask your fish experts — the fish warden, the one who has charge of the nearest hatchery, or some of the best local anglers — to visit the class and present their views for stocking the district. Study the publications of your state fisheries commission and of the United States Bureau of /i; f Topography of a fish (Yellow perch) 1, spinous portion of dorsal fin ; 2, soft portion of dorsal fin ; 3, caudal fin; 4, anal fin ; 5, ventral fin ; 6, pectoral fin ; 7, opercle ; 8, branchiostegal rays ; 9, mandi- ble, or lower jaw ; 10, premaxillary ; 10 o, maxillary ; 11, snout ; 12, eye ; 13, head ; 14, lateral line ; 15, series of scales, counting from front of anal fin upward and forward to lateral line Fisheries. Ferret out all such bulletins in private collections and induce their owners to loan or donate them to the school or public library ; and write to Washington or to your state department for any others that may be needed. 1 "It is difficult to estimate the capacity of ponds for the various stages in the growth of fish. It depends for the most part upon the amount of ap- propriate food available. A 2-acre pond producing 10,000 one-year-old black bass from 4 to 6 inches long would be a remarkably successful enterprise, and 20,000 one and one-half to two inch yearling crappie or sunfish to an acre of water would be likewise notable. These numbers have been realized and in some instances exceeded, but the average results are doubtless much smaller." — Johnson and Stapleton, loc. cit., p. 25. PROBLEMS OF FISH AND FISHING 299 Finally, draft a plan for stocking and maintaining the waters of the district at their maximum production, and have this printed hi the local papers. Fishes Day.^ We have Bird Day and Arbor Day and Apple Day. Why not have Fishes Day ? We ought to know our fishes better. We ought to know their habits and habitats, their foods, and especially their nestmg and spawn- ing seasons; and if we did, it would come to be considered as much an outrage to take a fish from her nest as to kill a mother bird on hers. When we all know these things and come, as a whole people, to have a right feeling for them, we may then combine in- telligently to have our waters teeming with all the best fishes they are capable of supporting. Aquarium manage- ment. This may be used as a key to the solution of our problems. A " balanced aquarium " is one in which just the right proportions of animal and plant life are maintained, with the right amount of light, so that the water remains clear and sweet. This means that there are plants enough, under the light admitted to the aqua- rium, properly to oxygenate the water for the animals, and ani- mals enough to supply the carbonic acid and nitrogenous wastes Fig. 140. Bluegill sunfish — best fish for pond culture Photograph by Reighard 1 Anglers often wonder why the fishes do not interest the public as do the birds, as they are also attractive and their habits interesting, indeed, fasci- nating. The reason, possibly, is, that birds are always in sight, while it takes searching to find the fishes. — Holder and Jordan, "Fish Stories," p. 226 300 CIVIC BIOLOGY which the plants require for healthy growth. The common mistake of beginners is to overcrowd the aquarium with both animals and plants ; more waste matters are produced than are continuously used, and bacteria develop and foul the water. Too much light is the other common danger ; this results in the excessive growth of algae, which green the water and overgrow the glass. A pond receives light only from above, while the aquarium may be lighted from the sides as well. Hence aquaria do better in north or east windows, and even here must be provided with cardboard shades to shut out almost all direct sunlight from the sides. South and west windows may be used if three sides are shaded and the top partially shielded from direct sunlight if algae become troublesome. Great care must be exercised not to overfeed, because uneaten food will decay and quickly fou> the water. In an aquarium properly planted with good oxygenators — temperature of the water not allowed to go over 15°-18° (60°-65° F.) — two fishes 3 inches long per gallon is the rule. Large specimens cannot be made comfortable in small aquaria: consequently small ones must suffice for schoolroom demon- stration and study. Predacious fishes (pickerel, basses, and sunfish, eels, and all except the smallest catfishes) should ordinarily be kept, each kind and usually each size, in a sepa- rate aquarium ; and it will be necessary to watch them and to remove any vicious specimen or to partition it off with a pane of glass. In equipping a laboratory or in planning an exhibition it is better to have a considerable number of small and medium-sized aquaria — easy to set up and each with its own distinct and clearly labeled exhibit — than to have a few cumbersome aquaria with impossible or difficult combinations mixed up in them. The temptation is to make aquaria too big. Taking the dimensions Q-iven on page II, we have the following data for approximate capacity PROBLEMS OF FISH AND FISHING 301 in gallons and weight of water. Any size can be figured, 231 cubic inches (weighing 8.34 pounds) being a gallon. Si/.i: Gallons Pounds Number requiked for a Class OF Forty fVidth Jfeiylit Tftickiu'ss 5 X 7 X 4 "] .66 1 5.0 "1 ^40 (1 apiece), used for insects, 8 X 10 X o y 10 X 12 X 0 J 1.7 I 3. J 12.8 I 25, J *j fungi, and feeding tests with Ismail animals. 20 X 12 X U 0.4 78.4 4-1 2, used for demonstrations 24 X 18 X 12 22.4 186.8 2, used for demonstrations Demonstration aquaria are usually })uilt into the walls so as to be lighted from above and viewed through the glass from inside the room. This arrangement can be imitated by setting the aquaria on suitable supports just outside the windows, on the window sills, darken- ing the outer glass (or making the ends and outer sides of slate). When we begin to realize the value of aquatic biology, we shall build uur aquaria into the basement walls, and then, by proper placing and grading of tlie building, we can have abundance of room for either still- water or running-water aquaria, under conditions as normal as those of natural ponds and streams, with which to study all manner of prob- lems. If the aquaria were figured into the original j^lans, they might cost nothing and the basement walls might be even less expensive than the usual solid construction of stone or brick. Our commissioner of fisheries says ^ : " This is a wide field ; I do not know of any more promising field in the government service than in the culture of fish. The possibilities of making new discoveries, especially in the line of intensive breeding and selective breeding, are almost inexhaustible. I would expect that a tremendous boom to the fish industry of the entire country would be given by a fisheries school such as this if established here." The still-water aquarium is the only kind recommended for ordi- nary school use ; running water is not at all necessary for most fishes, 1 H. M. Smith, California Fiah and Game, Vol. I (July, 1915), p. 189. (From remarks before the Pacific Fisheries Society, Seattle, on the plan of establishing a school of fisheries in connection with the University of Washington — on a par with schools of forestry and agriculture, mining and commerce.) 302 CIVIC BIOLOGY and danger of a stoppage of escape pipe, and consequent flooding. of building, is too great a risk. The absolute rule should be that one person shall take the sole responsibility for an aquarium, and no one else be per- mitted to put anything in or take anything out of it. As long as the aqua- rium is properly balanced and managed, the water need never be changed. Water is always water, and as it evaporates, clean pond or brook water ^^^HHHHhHIh^ Ji r s ■^ II W • ' ' i^^S ¥^M ^ a. '•»'*-t«,„„^r^^^^BB*J^^^^H dlMl^B^ ^,^m Fig. 141. Biological Laboratory, Cleveland Normal Training School View of the west end, showing three of the four large aquaria built into the wall under the windows, and a small greenhouse opening out of the laboratory i must be added to keep the level about constant. If adding any consider- able quantity, allow the water to stand in the room a day, or until it is of the same temperature as that in the aquarium ; for even small changes of temperature, if sudden, may be injurious, or even fatal, to some fishes. The hand should never be put into the aquarium ; it carries too many troublesome bacteria. Use the proper tools — dipping-tubes and siphons, dip-nets and scrapers. A spirit of good-natured rivalry should be 1 The architect overruled the location of these aquaria in the north wall and changed their specifications. They should be two feet, instead of about one foot, deep, bringing the bottom two feet from the floor and giving double the depth of water. The glass roof, if present at all, should be raised to the middle bar of the window, and the flap, which can be lowered to shut the space above the aquaria from the room, should be two feet wide. PROBLEMS OF FISH AND FISHING 303 encouraged, to see who can have the most beautiful aquarium and the most instructive one, and hold it longest without change of water. A de- merit mark is deserved, and may be given, for every time a pupil permits the water in his aquarium to become foul enough to require changing. In this way, by gaining experience through the year, the students may keep the aquaria running in fine balance, each with some specimen of native fish, and so afford a most instructive exhibition. This may be held in connection with appropriate lec- tures by specialists and a general discus- sion of the plans which have been worked out for the adequate stocking of local waters. Whether we call it Fishes' Day or make it a feature of more general exer- cises will depend on community interests and preferences. A few important features of such an exhibition may be 1. Species of value and relative impor- tance of each. 2. Habits and proper habitats of each species (so far as these can be shown by arrangement of aquaria). 3. Table of spawning seasons ; pre- served specimens of eggs and fry ; photo- graphs and other pictures of fish nests ; diagrams of local waters, with distribution of nesting places of different species. 4. Eggs actually being hatched (Fig. 142) and fry being fed and reared for distribution. 5. Foods of different species, with natural food supplies. 6. Extermination of mosquitoes by fishes, with data from feeding tests in the school aquaria and from park or pond waters properly stocked. 7. Data of growth of different fishes, fed in different ways. 8. Diagrams and records of production of home fish ponds. (Why not have fish projects and fish clubs as well as corn clubs and pig clubs?) 9. Enemies of different fishes, and means of their control. 10. Fish course, composed entirely of local varieties in season, prepared by domestic-science classes for the exhibit luncheon. Fig. 142. Tumbler hatchery Water running through funnel keeps eggs aerated. Author's design 304 CIVIC BIOLOGY 11. One or two of the most wouderful curiosities of fish natural his- tory : a nest of sticklebacks, " nothing short of marvelous " (Hornaday), or a paradise fish with his nest of bubbles; or exchange with coast schools and devote one of the large aquaria to artificial sea water and marine forms. Classification and species. About as many different khids of fishes as of birds are known to science (13,000, Galloway), but more than four times as many fishes as birds are found in the inland and marhie waters of North America (3263 species).^ Any list (published by your state fish commission or by the United States Bureau of Fisheries) giving the dis- tribution of fish and fish eggs for the preceding year will contahi about fifty of the more valuable food and game species, and from this we may choose the most instructive types for study.^ Ponds as balanced aquaria : foods and overstocking. The work with aquaria may be made to help in understanding- how to keep park waters and reservoirs in good condition. Lack of proper balance results in foulmg the water, and is accompanied with offensive odors and appearance. The fishes die, beginnmg with the, more overcrowded or more sensitive kinds, and ending with the catfishes, which can live in fairly wholesome mud. Probably in most such cases the prime reason why the fishes die is because they lack proper 1 Jordan and Evermann, Descriptive Catalogue of North American Fishes, 3313 pages, 392 plates. "The work has been carefully devised to be of no use whatever to anyone save an ichthyologist'' (Hornaday). 2 The list recommended for pond culture is as follows : black basses (small-mouthed and large-mouthed), crappie, calico, rock, and warmouth basses, the bluegill sunfish, and the catfish, or bullhead (either Ameiuriiti nebulosus or A. n. marmoratus, a variety known in the South as the marble cat). Strong local prejudice and lack of outward beauty are against the humble catfish, but for edibility Dr. Jordan has placed it above all the basses, perches, and pikes, and just below the trout, salmon, and whitefish. The bluegill is the only sunfish recommended for use by the Bureau of Fisheries, ''and it is believed to be the finest pond fish available for private culture." — JouNsox and Statlktov, loc. cit., p. 18. PliOBLEMS OF FISH AND FISHING 805 food; that is, if they were thriving and growing, they would resist attacks of saprolegnia or other disease germs. A variety of plants and animals is essential in a balanced pond if it is to supply food continuously to all its inhabitants. As witli similar problems on land, the most necessary thing is an abundance of plants, to supply food for snails, mussels, in- sects, worms, Crustacea, and vegetable-feeding fishes; then mussels should be present in sufficient numbers to strain out any excess of floating algse and fungi ; and, finally, there nmst be enough carnivorous forms to prevent exces- sive multiplication of the vegetarians. Of course this natural bal- ance of lakes and ponds is a more complex mat- ter than that of our aquaria, since these are never required to pro- duce all the foods of the fishes. Fig. 143. Tray of wild-trout eggs, with mos- quito net and moss in which they were packed United States Burea\i of Fisheries Even good-sizeecies continue to feed mostly on insects. Adult fishes possessing fine gill rakers continue to strain out the minute Crustacea; those with heavy, blunt teeth feed largely on mol- lusks; and worms play but a small part in the food of fresh-water fishes. Spawning habits and seasons. Brooks's law, as stated in its application to the lobster, with the diagrams illustratmg it, applies with equal force to food and game fishes. With the powerful machinery at his disposal, man strikes all species as a catastrophe and not as their natural enemy ; and he must make good his attack by intelligent dominion or lose PKOBLEMS OF FISH AXD FISHIXG 309 fa o 73 =C b( Si 03 S is 11 H 35 O s "^ Ox O S a OQ * e8 M « a; Jl a 5C 9 ?^ 2^ S«^ I -^J 4^ If: 'M 8 iJ S g 5 ^ «.S 5^ > CO ^ S O ^ ^ 'i g S ^ - 8 S3* ^ fa 03 ^ p b^b^ f^S >-.'t> o o 2 = _ -' li '5 ® — « - ^^ c a -;t-i a 03 5 03 © sx S ® s 2 P as -a t-l i o xi 2 1^ 3 o< p,-^o- ^ ^^3 - ^ S c *>• «~ •?* cf ^: ii '^di'S^ ■it -a^ ■•;§' a «c J3 o ^ ■ s ^ ^. BIO CIVIC BIOLOGY the species. The large numbers of eggs produced by fish indicate how quickly we may have our waters abundantly stocked, as soon as we learn enough to cooperate in leaving a sufficient number of adult spawners and in insuring protec- tion of eggs and young from their natural enemies. The data in this field must be worked out in connection with the local surveys suggested above. The table above is offered merely by way of further suggestion. The biology class in each district should have its own table, developed to give local dates and precise breeding places, so that all may know how, when, and where to protect effectively all valuable species during their spawning seasons. This knowledge may be of advantage in exterminating pest species, such as garfish and dogfish. Economic and civic values. To doubt the value of fish culture would be as absurd as to question that of agri- culture. For the United States, including insular posses- sions, an invested capital of $79,000,000, with about 165,000 people employed, results in gathering a food product amount- ing to 191,073,000 annually. The fishes do most of the work, foraging in the boundless food-wealth of the ocean and then, like the shad, salmon, and others, bringing it up our rivers and to our very doors. As the cost of food advances, we are beginning to ask what are the possibilities of supply from our waters. The brief table on the next page may serve to indicate the problem for the species named. Sport fishing also carries civic values and yields annual returns, not only in catch but in health and pleasure, of possibly no less importance to the country as a whole than the commercial fisheries. It gives employment to thousands in the manufacture of tackle and boats, stimulates travel, and supports many special outing resorts. Is not good fishing an asset to any community, well worth careful study and conservation ? PROBLEMS OF FISH AND FISHING 311 Shad, Atlantic . . . Shad, Pacific . . . . Salmon, Atlantic . . Salmon, Pacific . . . Total fresh-water fish Value of Present Yearly Catch $2,085,200 22,000 3,700 3,342,700 12,000,000 Value of Possible Yearly Production^ 1 This table was submitted to the United States Bureau of Fisheries, but no estimates were available. Dr. George W. Field estimates that under proper management the marine and fresh waters of Massachusetts might be made to yield f 50,000,000 worth of products annually. Fig. 145. Toad catching ants Photograph hy Newton Miller Fig. 146. Toad exposed in its hibernation cavity Note protective coloration and granulation of skin in relation to earth. Photograph by Newton Miller 312 CHAPTER XXVIII AMPHIBIA: SIRENS, PROTEANS, SALAMANDERS, FROGS, TREE FROGS, AND TOADS For an insectivorous animal which conforms to every requirement of the situation — ease of control and rapid increase, noninjurious in any numbers, an active feeder in abundance and a patient faster in scarcity — the toad stands probably first on the list among American insectivorous animals. — Miller, "Biology of the American Toad," American Naturalist^ Vol. XLIII (1909), p. 643 The amphibia are a relatively small group of about 1400 species, of div^erse kinds (from wormlike Ccecilians, through the two-legged and four-legged sirens and salamanders, to frogs and toads) — aquatic, semiaquatic, and terrestrial — form- ing, as the name implies, a transition series from the fishes to the higher land animals. All amphibia are carnivorous, many of our common forms ranking with birds as efficient destroyers of insects ; and as a group they cover the whole field, for salamanders, bullfrogs, and other aquatic species hunt the waters of our ponds and streams and their immediate shores, wood frogs and toads and many of the salamanders follow insects of the ground both by day and by night, and tree frogs are especially adapted to feeding upon insects of forest and orchard.^ Amphibia belong exclusively to fresh waters and the land. They are comparatively small, the largest modem amphibian being the giant salamander of Japan, which is said to reach a 1 Hornaday's statement, '' With very few exceptions, the amphibians are quite useless to man " (Natural History, p. 360), is evidently made without due regard to their powers of insect destruction or even to their uses as fish bait. 314 CIVIC BIOLOGY Fig. 147. Laying cf a toad — 15,835 eggs Photograph by Newton Miller length of 6 or 7 feet. Gigantic species formerly disported in the vast swamps that have given us our coal forma- tions. With few exceptions, amphibia deposit their eggs in water, and they all pass through a truly larval stage, the " tadpoles " being fish- like— aquatic, legless, and breathing by gills. In ad- dition to insect destruction by the adults, the tadpoles perform an important serv- ice by eating all manner of slimes and scums and decaying animal and vegetable matter, thus helping to purify surface waters. Aquaria with and without tadpoles may be made to demonstrate this point in a strikmg manner, and the results may well be applied to the problem of cleansing local park and reservoir waters. Natural history of local species. In connection with other outdoor work, collect all the different species of toads, frogs, tree frogs, newts and salamanders, mud puppies, and sirens common to the locality. Special interest attaches to spawning habits and sea- sons, since knowledge of Fig. 148. Different portions of single laying of toads' eggs The top specimen shows the usual arrange- ment; the other two show the crowding and irregular spacing of the eggs in the gelatinous tube near the end of the laying. Photograph by Newton Miller AMPHIBIA 315 these data will enable a community to give effective protec- tion to valuable species. Frogs and toads proclaim this sea- son, each species with its own peculiar note, from the earliest shrill whistles of the spring peepers, and the croaks, clucks, trills, and warbles of the frogs, toads, and tree frogs, to the bass-viol br-wums and jug-o-rums of the bullfrogs in late June and early July. The eggs are most interesting forms with which to follow embryological development, and their numbers indicate possi- bilities of increasing val- uable species, when we learn to provide favor- able conditions. The toads' eggs are found in strings ; the green frogs' and bullfrogs', in loose, floating films ; the wood frogs', leopard frogs', and pickerel frogs', in globu- lar masses of jelly; and the peepers', single or in small clusters. Observa- FiG. 149. Toad tadpoles as scavengers, eat- ing dead pout at margin of pond Photograph by Newton Miller tions by the class may yield a table for local species some- what like the one shown on the following page. The feeding test. Amphibia afford most convenient ani- mals with which to study foods and feeding habits. Imitate natural habitats in the arrangement of terraria and aquaria — moist earth, moss, or sod for toads, wood frogs, and land salamanders, with a forked branch and a small pool for tree frogs, and a larger pool, with a bank of moss at one end, for aquatic frogs and salamanders. Then, for the tests, introduce all sorts of insects, spiders, millepeds, crustaceans, slugs, and worms, counting the numbers and kinds eaten. No single laboratory exercise shows so convincingly the value of the ai6 CIVIC BIOLOGY o ^ as -< ?S.^S 8 g" 8 ce ^ '^ ^ J: i ^ oi T- ,-1 oo I III ^ 1 I ^"§ ,-1 CO '"' S i2 >H ^ ^ H, ca p ^ 2 *^ £2 O O 5 be ^ cS CD d --5 = 8 -c 5 ^ « pq o ^^ Ph ^ f ^ »5 .^" r. o b >. S 3 i ■-3 O H p^ hop; CO 00 a Ph O CO -^^ 't. M^ c; 02 ^ OQ 't3 CD U cS 'd ^ cc O o > •->, ^ o ^ Ti 03 ? S « S s (-H 03 XJ +2 a) > ?i P5 li ^ Oh O O .r:3 bJD 5S bC o o . 03 5zi AMPHIBIA 317 work of a species. Different members of the class may take different species, and the data obtained should be applied to solving the insect problems of the locality. Almost all insects come to the ground at some time, and we have, especially in the toads, a possible force of insect police that ought to be better known and utilized. Commercial values. Toads are regularly sold in the markets of Europe, being used by gardeners to control insect pests.^ Is there any local mar- ket for them? Could such a market be developed as a result of studies and demonstrations to prove their value? The following numbers of insects have been eaten by a toad at a meal or were found in a toad's stomach : 90-100 rose beetles (Pollen M. Foskett) ; 55 army worms, 77 myriapods, 65 gypsy-moth caterpillars (A. H. Kirklaud, in three stom- achs) ; 24 gypsy-moth caterpillars (fourth molt), taken in ten minutes (Wilcox); 86 house flies, snapped up in less than ten minutes (Hodge). From examination of 149 stomachs, Kirkland^ estimates that a toad will eat, in the three months of May, June, and July (why he does not in- clude August and September is not stated ; these months would add materially to the account), .3312 ants, 2208 cutworms, 1840 myriapods, 2208 sow bugs, 368 weevils, and 368 carabid beetles. Subtracting the cutworms that might have been killed by the carabids, we have 1988 cut- worms to the toad's credit. He estimates the killing of these as worth one cent a piece to a gardener, and thus, for cutworms alone, the possi- ble value of the toad's work is $19.88 for the season. Miller ^ is more conservative and estimates a toad's work for a season at, possibly, about $5 "for greenhouses, gardens, and truck farms" and not so much in ordinary farming districts. Frogs, especially bullfrogs, are much more inclined to feed ujkju ani- mals other than insects — fish, birds, crawfish, and, above all else, upon other frogs. This is the great obstacle to frog culture — except on paper. No matter how many we succeed in bringing through the tadpole stage, we have few big frogs in the end. The difficulty in feeding frogs arti- ficially is that they take only active, moving, hence living, food. It would 1 Kirkland states {Farmers'' Bulletin No. 196, p. 14) that English gardeners pay |25 per hundred. 2 Kirkland, Hatch Experiment Station, Bulletin 46 (1897), p. 27. 8 Miller, '' The American Toad," American Naturalist, Vol. XLIH (1909), p. 668. 318 CIVIC BIOLOGY seem entirely possible to solve the problem of supplying such foods in quantity and variety that would largely prevent even the bullfrogs from eating each other. We might have lighted insect traps to deliver their catches of moths and beetles all night long into the water beneath them ; EiG. 150. Toad tadpoles (broad, dark margin of pond); young toads emerged and moving landward (irregular gray edge of shore) Photograph by Newton Miller sweeps designed to catch grasshoppers alive ; blowfly maggot hatcheries, made to drop the maggots into the water as they ripen ; or, if all these should not suffice, crawfish and the smaller species of frogs could be added. Meehan^ states that "30,000 tadpoles have been safely carried 1 Meehan, "Possibilities of Frog Culture," Country Life in America (1908), p. 315. AMPHIBIA 319 Fig. 151. Common tree frog Photograph by Millett T. Thompson to frogdom in a pond 30 feet by 15, having a depth of 2 feet of water." As eggs of leopard frogs, pickerel frogs, and wood frogs can usually be gathered in any desired quantity, this would indicate almost unlimited possibilities of live-food production. In addition to their uses, actual and potential, as insect traps, frogs have com- mercial values which threaten their exter- mination in many localities. In some places small ones bring from $1 to |2.50 per 100 for fish bait. The frog is the animal most commonly used for laboratory study the world over ; frogs used for this purpose bring from 50 cents to $3 per dozen. More- over, while they were rarely used for food a few years ago, frogs' legs have now be- come a well-known delicacy. "The meat is white, delicate, and very wholesome and palatable." Hence catching frogs for mar- ket often yields good profit, and it affords a mildly humorous form of outdoor sport. As these values come to be recognized, valuable species can be protected by closed seasons (from the opening of spring until after they spawn), local waters can be kept stocked to their full capacity, and an abundant crop can be secured each year. Some special problems. 1. In a pond stocked with bullfrogs, how can we feed so as to prevent cannibal- ism and thus secure the greatest number of large specimens from a given area? 2. How can the largest number of toads be reared from a pool a foot square and a foot deep? (We have one record of 3938 from April to August ; the main foods were algae, dog biscuit, and fresh fish.) 3. Are toads being exterminated from agricultural districts by drain- ing their breeding pools, by farm animals, and by the operation of farm Fig. 152. Pair of spotted salamanders Photograph by Millett T. Thompson 320 CIVIC BIOLOGY machinery? Could this be prevented? If so, how? Might it be worth while, as a measure for insect control, to try the experiment of stocking a farm with them, and comparing the damage done by insects on such a farm with that on a similar farm where there are no toads? Elementary classification and distribution. The names at the head of this chapter present the main groups of amphibia in ascending order. They are placed there to serve as handles by which any form that is of local interest or im- portance may be looked up in the dictionaries, natural histories, or zoologies. Jordan's " Manual of Ver- tebrates " describes eighty-one species of salamanders for the United States. So little is known about their habits, foods, spawning seasons, and general natural history, that they offer an almost virgin field for young American nat- uralists — a field that needs working the more on account of senseless prejudices con- cerning the venomous char- acter of these harmless and valuable animals. The mud puppy (Nectuj'us maculosus) of the upper Mississippi and Great Lakes basins destroys the sj^awn and young of fishes, but this is the only one of the tailed amphibia that is considered harmful. Recent books describe fifty-three species of the tailless amphibia as native to the United States — the frogs, tree frogs, and toads. Of the fourteen species of toads the greater number occur in Texas and south- western United States, indicating this region as the probable center from which the group has spread over the continent. Fig. 153. Coast newt depositing eggs in an aquarium Photograph by Loye Holmes Miller CHAPTER XXIX REPTILES: CROCODILES, ALLIGATORS, TURTLES, TERRAPINS, TORTOISES, LIZARDS, SNAKES However, the Reptilia take up a very central position in the evolution of the main classes of the Vertebrata. On the one hand, there is not the slightest doubt that they are evolved from some branch of the Stegocephali, whilst on the other hand the reptiles, probably through some branch of the Theromorpha, have given rise to the mammals ; some other reptilian branch, at present unknown, has blossomed out into the birds. — Hans Gadow, "Cambridge Natural History," A^ol. VIII, pp. 277-278 In the absence of birds, what, then, holds the devastating hosts of insects in check, for insects abound in all warm countries where vegeta- tion is luxuriant ? This, in my opinion, is the lizard brigade, — those spry and cheerful little fellows in brown "homespun," of which La- certa muralis is the commonest kind, which are seen streaking it over walls and along the ground, in town and country everywhere. — F. H. Her- RiCK, " Italian Bird Life as it impresses an American To-day," Bird Lore, Vol. VIII, p. 196 Why may not a good snake merit the same protection as a good bird ? The reason is that we have not taken the pains to know the good from the bad, and our prejudice and fear, the children of ignorance, have dominated the field. As venomous snakes have been almost exterminated from inhabited parts of tlie country, we are coming to be able to appreciate the beauty and acknowledge the good there may be even in a snake. In general a reptile is a good citizen if it does good work in the world, if it feeds upon injurious insects or upon rats and mice or other harmful animals, and if it is not venomous. In addition to this larger aspect, a number of reptiles supply valuable products — alligator and 321 Fig. 154. Rattlesnake coiled to strike After Ditmars Fig. 155. Copperhead After Ditmars 322 REPTILES 323 snake-skin leathers, the tortoise shell of commerce, and the flesh of some of the marine turtles and fresh-water terrapins. Here is a wide, almost new, field, and anyone who will make careful studies of habits and life histories, especially of feeding tests with snakes, lizards, or turtles, and even tests of edibility in case of likely forms, has a good chance of advancing the cause of valuable knowledge and common sense. Crocodilia.' The warm regions of the world contain nineteen species of big, burly, bony-armored reptiles, with long tails, powerful jaws, and tempers as ugly as their own rough backs. — Hornaday. To see a live Alantosaurus immanis 115 feet long — said to be the " biggest and bulkiest of all animals " (Gadow) — would make us real- ize that our largest 20-foot crocodiles are mere pigmy survivals of the huge reptiles that ruled the world during the Upper Jurassic. Accord- ing to Hornaday only three of the nineteen species are dangerous man- eaters — the Malayan salt-water crocodile and two African forms. The. two that are natives of America, Crocodilus acutus and Alligator missis- sippiensis, are not man-hunters. Still, to keep such hulks in food — con- sisting of fishes, waterfowl and poultry, pigs, and other animals such as they can catch — is expensive and must eventually limit their range to zoological gardens and alligator farms. Turtles — Chelonia. Senseless waste and even cruelty have too often characterized man's treatment of these defenseless and valuable crea- tures. Their nests have been plundered for the eggs, whose value is slight compared with that of the turtles which they might have pro- duced ; the mother turtles, when they draw out of the sea to lay, have been turned on their backs in numbers that could not be utilized, and most of them left to struggle under the hot sun until they died ; the hawksbill, in some countries, is hung over a slow fire and roasted until the precious shell plates loosen from the bone, when they are stripped off and the turtle is put back into the water under the probably false idea that it may live to produce another crop of shell. These are some of the abuses that ought to be stopped in the name of humanity. While it may be a far cry to ask savages of cannibal islands to treat sea turtles with humanity, we might, at least, see that turtles of our own coasts are treated in humane and common-sense fashion. They range the tropical and subtropical oceans the world around, but Gadow says that they prob- ably return to the same beaches to lay. Hence, if we protect the turtles 324 CIVIC BIOLOGY Fig. 156. Common snapping turtle of our own southern coasts, and especially their eggs, we may hope to in- crease the American supply. May not classes in biology work up local statements of this problem and help to develop public sentiment? Of the four species the green turtle {Eretmochelys mydas) is most highly prized for food. AVhile formerly speci- mens weighing 600 pounds were cap- tured, now specimens weighing more than 50 pounds are rarely seen. The \og- gerhe&d (Thalassochehjs caretta) is coarser and does not command so high a price, but may not be distinguished from prime beef even by a butcher (Hornaday). The hawksbill (E. Imbricatd) supplies the tor- toise shell of commerce, but is not used for food. The harp turtle, or leather- back (Sphurtjis coriacea), the largest of all, is said to be unfit for food. Terrapins and tortoises. The diamond-backed terrapin (Malacoclem- mys palmtris) is so renowned a delicacy with the epicures that extinction of the species has seemed imminent. It formerly ranged from Massa- chusetts to Mexico (the Chesapeake being a center of special abundance), inhabiting the salt marshes and feeding upon Crustacea, small mol- lusks, and marsh vegetation. Prices have risen from %^ a dozen for large ones to $70 for small ones, and this has so stimulated the hunt for them that a well-grown sjiecimen has be- come a curiosity in the wild habi- tat. Experiments of the United States Bureau of Fisheries, the re- sults of which are given in a recent bulletin, have proved that this terrapin may be profitably reared in inclosed tide pooh tide flats are thus beginning to be used for terrapin farms. The common snapping terrapin, or "turtle" (^Chelydra serpentina), and the alligator terrapin (Macrochelys temmincki) of the Gulf states, while valuable for food, are "demons of the deep" (Thompson Seton) for destroying waterfowl and fishes. United effort should be made to ex- terminate them from waters where rearing of waterfowl is an industry, Fig. 157. Common box tortoise Waste REPTILES 325 and from the natural breeding grounds of wild ducks and geese. The most effective means of doing this would be to find their nesting banks and destroy the eggs or catch the turtles at night, when they leave the water to lay. A female may produce from 2 to 4 dozen eggs. The soft-shelled terrapin {Aspidonectes ferox) is said to be the best of all the fresh-water forms, even the shell, properly cooked, being considered a delicacy. They are, however, vicious destroyers of fishes and waterfowl. Any of the smaller mud, or pond, terrapins, painted or spotted, and the land tortoises, offer interesting problems in the study of foods and possible edibility. The common box tortoise (^Cistudo Carolina) makes an interesting pet, and its appetite for slugs renders it a valu- able assistant to gardeners. The gopher tortoise {Testudo polyphemus) of the South may attain a weight of 15 pounds. Tt is considered edible. The annual catch of food turtles, terrapins, and tortoises amounts to about 1,400,000 pounds, valued at $114,500. What it might be if these re- sources were properly handled has never been estimated. Lizards — Lacertilia. The Fig. 158. Common lizard lizards are an effective in- sect police for hot, dry habitats not covered by amphibia. They are difficult to keep in a laboratory, but if we have a sunny window, in which we can imitate desert conditions, we may make valuable feeding tests with a number of the commoner forms — the blue-tailed lizard, or skink (^Uumeces fasciatus'), the fence swift (^Sceloporus undulatus'), and one of the horned toads, or the chameleon (^A^ioUs carolinensis). This may help us to realize the importance of the group in nature. Lizards are clearly distinguished from all salamanders of somewhat sim- ilar form by being covered with scales. None of our 97 species of small, agile lizards are in any way harmful or dangerous. The Gila monster (Heloderma suspectum) of the arid South- west is the one venomous lizard native to the United States. 326 CIVIC BIOLOGY Snakes — Ophidic. About 140 species of snakes are native to the United States, of which 17 are venomous. They are all strictly carnivorous, and the nonpoisonous species are beneficial or injurious, according to their foods. It is clear that snakes which specialize on insects or on rats and mice should merit general protection. Our little brown and green Fig. 159. Aquarium (24" x 18'^ x 12") made by student and stocked for study of native snakes Photograph by the author snakes feed on insects, and the corn snake (Coluber guttatus), ofteii called the rat snake, and the gopher snake (Spilotes corals eouperii) are often protected about the farmsteads of the South for their services in holding rodents in check. The snakes that feed upon birds and birds' eggs (the black snakes or the blue or green racers), those that feed on frogs and toads (the garter snakes and the blowing adder, or spreading adder), and those that feed on fishes (the water snakes) must be studied with care and treated according to local conditions and interests. KEPTILES 327 Poisonous snakes. Fortunately none of our venomous snakes tend to infest houses, as does the hooded cobra of India. In consequence, snake bites are extremely rare with us, and probably not more than two deaths occur annually from this cause (Hornaday). Of the 17 venomous species 13 are rattlesnakes, belonging to the genera Crotalus and Fig. 160. Blowing viper, trying to make room for one more ^. ^ Photograph by- the author Sistrurus (the massasaugas), so well known, so clearly dis- tinguished by the rattles, and so nearly extinct from all settled regions, that they require no description. It is proba- bly safe to say that a rattlesnake strikes only in self-defense and that it never gives chase. When coiled it cannot strike more than one third of its length, and much less if the neck is drawn into an S-shaped loop, and its rasping buzz gives a warning that is readily understood by both animals and man. Closely related to the rattlesnakes are the two moccasins — the upland moccasin, or copperhead (^Ancistrodon contortrix), and the ugly water moccasin (.1. piscivorus'), often called the cottonmouth. The copperhead is found among rocks and in woods from Massachusetts to Florida, ranging westward to Texas and northward to Indiana. The water moccasin inhabits the swamps and grassy shores of the bayous of the Gulf states, feeding largely on fish and frogs, and on other snakes. 328 CIVIC BIOLOGY The two coral snakes complete the list of venomous species for the United States. These snakes do not in the least resemble the rattlers and moccasins. Their heads are slender, not broad and spear-shaped ; the pupil of the eye is round and there is no pit between the eye and the nostril. They look so harmless that, as Horn- aday says, " it is difficult to see how anyone can be bitten by this serpent without having it done by special appointment." This is all the more reason for having it definitely known that these snakes are venom- ous. They belong to the same family (Elapidce) as the deadly king cobra of India. They are instantly recognized by the brilliant yellow, red, and black rings that encircle the body from the head to the tip of the tail. The two species' are the harlequin snake (Elaps fii/rius), which ranges from South Fig. 161. Use of forked stick and noose in catchins: a snake Fig. 162. Coral, or harlequin, snake, with yellow band around head and also between the red and black bands of the body After Ditmars Carolina throughout the Gulf states to Texas, and northward up the Mississippi to southern Indiana, — a persistent ground dweller, most often seen when turned out of the furrow by the plow, — and the Sonoran coral snake (E. euryxanthus), confined to Arizona, New Mexico, and northern Mexico. REPTILES 329 Snake venoms and the treatment of snake bites. Dr. Calmette, of the Pasteur Institute, succeeded in proving that snake venoms act upon the body and are reacted against by the tissues like any other toxins. From this it has followed that antitoxic sera may be developed for different snake poisons, — the antivenins, — which are able to neutralize, the poisons and thus confer certain degrees of passive immunity. When this subject has been thoroughly worked out, we may have specific and sure remedies for all snake poisons, and this will do away with the old, ineffectual remedies — whisky, sucking the wound (very dangerous unless the mouth is perfectly sound), or instant ligature above the bite and quick excision of the poisoned tissues.^ 1 NoGouoHi, '^ Snake Venoms," Publication 111, Carnegie Institution, Washington, 1909. CHAPTER XXX PRACTICAL LAWS OF LIFE Geometrical Increase and Struggle for Life. Vari- ation. Selection and Survival of the Fittest. Heredity. Genetics. Eugenics It is good thus to try in iiiiagiiiation to give to any one species an advan- tage over anotlier. Probably in no single instance should we know v^hat to do. This ought to convince us of our ignorance on the mutual relations of all organic beings ; a conviction as necessary as. it is difficult to acquire. All that we can do is to keep steadily in mind that each organic being is striving to increase in a geometrical ratio ; that each at some period of life, during some season of the year, during each generation or at inter- vals, has to struggle for life and to suffer great destruction. When we reflect on this struggle, we may console ourselves with the full belief, that the war of nature is not incessant, that no fear is felt, that death is gener- ally prompt; and that the vigorous, the healthy, and the happy survive and multiply. — Charles Darwix, '' Origin of Species," p. 96 An exact determination of the laws of heredity will probably work more change in man's outlook on the world and in his power over nature than any other advance in natural knowledge that can be clearly foreseen. — Bateson, ''Mendel's Principles of Heredity," 1902, p. 1 To unravel the golden threads of inheritance which have bound us all together in the past, as well as to learn how to weave upon the loom of the future not only those old patterns in plants and animals and men which have already proven worth while, but also to create new organic designs of an excellence hitherto impossible or undreamed of, is the inspiring task before the geneticist to-day. — Walter, "Genetics," p. 5 It is as impossible now to take the ideas of descent and of natural selec- tion out of the world as to take a star out of the sky. — Cramer, " Method of Darwin," p. 61 Mankind is slowly discovering the laws of life. Ignorance cannot, in the nature of the case, bring exemption from the consequences of breaking laws ; hence failure even to try to 330 PRACTICAL LAWS OF LIFE 331 learn the laws under which we live niay amount to criminal carelessness. We discover and learn laws in order that we may be able to obey them, that is, bring our lives into har- mony with them. Charles Darwin, by lifelong application and sacrifice, marked the greatest advance in discovery of the laws of life that the world has known. These are not far-away abstractions of thought, and nothing can be of more intense practical value than a knowledge of them. Work done or life lived in accordance with them is always effective and successful, while that done or lived in opposition to them is always futile. While it may be sufficient that a few specialists learn how to control the chemical and physical forces of nature in accordance with the laws of physics and chemistry, the forces of living nature are so numerous, affect the lives of all alike so intimately, and are so powerful that common welfare re- quires of every member of a civi- lized community that he know enough about them to do his part. Law of geometrical increase. All living things tend to in- crease in geometrical ratio. This is the problem of the farmer who promised to pay the blacksmith one kernel of wheat for the first *nail in his horse's hoofs, two for the second, four for the third, and so on. The sixty-fourth nail alone would cost him 6,141,451,656,032 bushels of wheat — more than the en- tire wheat crop of the world for 2000 years. The farmer did not know the law of geometrical increase when he promised to pay the wheat. Millions of " farmers " who do not know this law are promising to pay, in control of insects or fungi Fig. 163. Diagram showing five generations doubling by geo- metrical progression 332 CIVIC BlOLOCxY and in many other ways. Fig. 163 expresses this relation to the eye, showing how quickly the world may be covered or any limit be reached, whether of space or food supply, by the geometrical increase of a living species. Each species has its own formula or equation of increase, its terms depending on the number of eggs, seeds, or offspring and the length of life of a generation. Every species that Ave need to control or exterminate, or which we wish to save or increase, finds expression for its power of good or evil in this law of increase. The mythical labors of Sisyphus typify humanity struggling with these problems. He w^as condemned to be eternally rolling a heavy stone up a mountain, the stone slipping and rolling down again when he had almost reached the top. Flies, rats, mosquitoes, or some other plague, become unendurable, and the community tries to rid itself of them. It rolls the stone almost to the top of the mountain. A little more effort, and extermination would be complete, the stone would be rolled over the summit and disappear; but those who do not know this law say, " Never mind these few, they can't do much harm." In a short time the work is all to do over again. So effective control or conservation can- not be developed until we have clear ideas of these equations of increase. Work out formulas of increase for all sorts of types, good or bad, and develop clearly their significance in solving local problems. The native American oyster-shell scale produces one generation (about 50 eggs) a year. Its equation of yearly increase is 2 (a pair) = 50. The Chinese (or San Jos6) scale brings forth about 500 living young in a period of 45 days, having four or five generations a season. Its equation of increase for a year is 2 = 3,216,080,400. What bearing has this upon thorough spraying of trees ? The native insect rarely injures a tree perceptibly. The imported scale threatens to exterminate many species of trees from the continent. The bobwhite has been known to produce 100 eggs in a season. Suppose each pair rears 10 young a year ; how long would it take, if PRACTICAL LAWS OF LIFE 333 everyone cooperated, beginning with present numbers, or with ten pairs, to increase them to limits of insect and weed-seed food supply ? Figuring the number of buds produced by a grape, peach, apple, strawberry, or other fruit, the number of eyes by a potato, the number of seeds by a grain or vegetable plant, how long would it take to supply every farm or garden with a favorable variation ? This introduces us to the second practical law of life. Law of variation. No tivo living things are exactly alike. Can we find two forest leaves, blades of grass, or human faces exactly alike? Living organisms are too complicated for it to happen, even by chance, that any two should be alike. So this universal law of living nature has given us all our different kinds of plants and animals. Domesticated plants and animals early attracted Darwin's attention as showing variations most clearly. ^ Horses, cattle, sheep, dogs, pigeons, and all manner of cultivated plants have varied in the brief centuries of human control, and are still varying, in most wonderful fashion. We have horses, from Clydesdales and Norman Percherons to Shetland ponies, all produced by human breeding and selection. Ages before man appeared on the earth little Eohippus, not much larger than a fox, with five toes, four of them hoofed, trotted over the bogs of the times ; and we can now trace in successive strata of rocks how the modern horse developed from this earliest form. The story of other animals and even of man himself we have not as yet been able to trace so clearly. The great practical values attaching to variations in relation to agricultural productions are touched upon in Chapter IX. Since these depend so largely upon the possibilities of increas- ing and propagating favorable variations, we must consider this subject further in connection with the greatest of all biological laws. 1 Darwin, Variations of Animals and Plants under Domestication. 334 CIVIC BIOLOGY Law of heredity. Organisms tend to produce offsprifig like themselves. Variation is as destructive as it is constructive. It may give us the Spitzenburg apple, and the seeds of a Spitz- enburg may revert toward the original wild apple. Heredity is the force that enables us to conserve the gains supplied by variation. Organic reproduction is of two kinds — asexual, or vegetative, and bisexual. The asexual process is seen in growth and simple division, as found among the bacteria, or growth with budding, as in the yeasts and in plants generally and in many of the lower animals. In all this reproduction we virtually have continuity of the organism, and this can go on indefinitely with little or no variation. So buds, grafts, cuttings (of stems or roots), layers, runners, bulbs, bulblets, tubers, and, in short, all purely vegetative parts of plants capable of reproduction carry the variety true to name. This means that every bud on a Spitzenburg apple tree, rooted in the ground or grafted into any kind of apple root or branch, will produce a true Spitzenburg tree, while not a seed from all the Spitzenburg trees in the world might be able to do this. There is some talk, but little evidence, that varieties tend to run out, or grow old, under bud propagation. Still bud variation does occur. A branch of an orange tree may bear lemons, or a bud of a peach tree pro- duce nectarines or apricots. Buds may also be weakened by association with disease organisms (as in diseased potatoes) or, possibly, by lack of proper nutrition, and so give rise to weakened stock. So we are beginning to hear of pedigree selection of seed potatoes from healthy, vigorous, productive hills, and of buds and scions from healthy and fruitful trees. If these pomts are attended to, there seems to be no reason why any variety may not by bud propagation be held true to type indefinitely. All higher plants have adopted bisexual reproduction as one method of multiplication (all seeds), and all animals PRACTICAL LAWS OF LIFE 335 higher than the worms and some msects have come to de- pend upon it entirely. In sexual reproduction each indi- vidual is built up by the mingling of the germinal elements of two parents, and not only that, but of four grandparents, eight great grandparents, and so on. This mingling, by pre- potefice of some characters and recession of others, causes active variation, and this seems to be the chief purpose of bisexual reproduction. By statistical analysis Galton proved that an individual receives on the average 50 per cent of his characters from his parents, 25 per cent from his grandpar- ents, and the rest from more remote an- cestors. Given all the forces of increase, va- riation, and heredity, another law comes into , , ,. „ Fig. 164. Diagram illustrating Mendel's law play, the discovery ot ^f dihybrids, white being dominant and which was Darwin's black recessive great contribution. The law of natural selection. Nature selects the fittest to survive. From the beginning, man has imitated nature in selecting the plants and animals that suit his need or fancy, and this is commonly distinguished as artificial selection. Combination of these two processes has resulted in the spe- cies and varieties, strains and breeds, that we now see m the world. Progress has been made in the past chiefly by pick- ing up chance variations as they have occurred in nature and accidentally among domesticated plants and animals. Only within recent years have we begun to learn how to select the parents in order to cause desired variations. By eight years of most accurate and painstaking experiments in cross- ing and rearing varieties of garden peas, the Austrian monk. 336 CIVIC BIOLOGY Gregor Johann Mendel, discovered a law of heredity, claimed to be equal, for biology, to the law of gravitation in physics or to that of atomic equivalents in chemistry. MendePs law. Characters are represented in genn cells by U7uts which tend to segregate or combine in definite propor- tions^ the result of mating together first crosses falling in the ratios IDD -h 2DR -h IBR for characters D a7id li. Illustration. A tall and a short pea are crossed. The seeds resulting from the cross produce only tall plants. When the seeds (self-fertilized) of these plants are grown, they are found to produce 75 per cent tall plants and 25 per cent short, or 3 tall to 1 short. Here tallness is dominant (character D) and shortness recessive (character R). A dominant character dominates the outward form of the plant or animal body, while a recessive character has its units persisting unchanged in the germ cells. When male and female germs again combine, they do so according to the law of chance (like dice, or any other free units) and so fall out IDD 4- 2DR -f- IRR. Since we cannot distinguish the DD plants from the DR plants, except by jilanting the seeds and analyz- ing the i)rogeny, we have 3D to IR. All the RR plants are found to be as pure and to breed as true as if they had never been crossed, and so are all the DD plants when we propagate them. The DR plants will continue forever to produce IDD -I- 2DR -f IRR. A hybrid can never 1)6 fixed so as to breed true. The above is the law for monohybrids — tt)rms in which a single character or pair of characters is involved, and instead of assuming the presence of a unit (determiner) for a character (for example, shortness), the tendency is to assume merely the absence of the germi- nal determiner for tallness. In cases of two characters being involved in each parent, that is, in dihybrids (characters Dd and Rr), there is IDd-Dd and IRr-Rr, that is, 1 pure dominant and 1 pure recessive in 16. In case of trihybrids only 1 offspring in 64 is pure dominant or l)ure recessive. If ten characters are involved, the offspring of the sec- ond generation would fall into 1,048,576 different kinds, of which only 1 would be pure for each set of characters. When we consider that this law of inheritance applies- to fixation of all kinds of characters, from tallness of peas to tallness of men, from rust resistance in wheat, egg production in poultry, or milk production of cows to feeble-mind edness or normal intelligence in men, we begin PKACTKJAL LAWS OF LIFE 337 to realize what Mendel has done for the world. As Walter sums up th«* case : " Thus in a few generations of properly directed crosses there can be obtained combinations of cluiracters united in one strain that formerly w^ere never obtained at all or were only hit upon by merest chance at long intervals. Herein lies the scientific control of heredity which the trinity of Mendelian principles, namely, independent imit characters, segregation, and dominance, has placed in human liands." ^ Historical. Mendel presented the re- sults of his era-making experiments before the Natural History Society in Briinn early in 1865, and they were published in the Proceedings in 1866. Neither the reading nor the publication caused a ripple of interest. No one un- derstood its significance. Had Darwin learned of Mendel's law in 1865, the liistory of human science, philosophy, and even religion might have been pushed forward fifty years. Mendel died January 6, 1884, bitterly disappointed that no one could be found to share his vision, and his discovery slumbered for sixteen years longer. In 1900, three men, working independ- ently, rediscovered Mendel's law almost at the same time. These were De Vries in Holland, Correns in Germany, and Tschermak in Austria. The time was ripe for its appreciation, and it immediately transformed the subject and, from a matter of abstract disquisitions, made heredity the most intensely practical concern of the experimental breeding plot and pen, of the hunt for variations in nature, and of even sociological analyses and surveys. " The practical breeder of animals or plants, basing his methods on a determination of the Mendelian units and their properties, will in many of his operations be able to proceed with confidence and rapidity. Lastly, those who as evolutionists or sociologists are striving for wider views of the past or of the future of living things may by the use of Mendelian analysis attain to a new and as yet limitless horizon." ^ Fig. 166. Diagram illustrating relation of germ plasm (straight lines) to somatoplasm (circles) in bisexual reproduction 1 Walter, Genetics, p. 144. 2 Bateson, Mendel's Principles of Heredity, 1909, p. 17. 388 CIVIC BIOLOGY Evolution, mutation, and Mendel's law. Tn his scheme of evolution Darwin emphasized the influence of slight variations continued through long periods of time. He. realized at the outset that in heredity, in the power to pass on variations, lay the heart of his problem, but he went far astray in his own theory of heredity, pangenesis,^ and so failed to attain the goal he might have won. No one realized this more keenly than Darwin himself. De Vries found that from the same seed capsule of Lamarck's eve- ning primrose he could rear as many as nine distinct kinds of plants, so different that, had they occurred consistently in nature, they might have been named as separate species. On the basis of these and similar experiments he advanced his recent theory of mutation. This theory supposed that evolution goes forward by leaps and sudden changes. It now turns out that this evening primrose, Gi,nnthera lamarckiana, is a Mendelian cross, a hybrid ; and this suggests that all mutations may be merely cases of segregation and recombination of unit characters in the germs of plants and animals, that is, outworkings of Mendel's laM^ Weismann made a solid contribution when he distinguished sharply between germ plasm and body plasm, or somatoplasm. He called atten- tion to the fact that the germs are all formed in the embryo long before the body; the egg-germs, and many more than a hen can ever hope to lay, are all set aside at almost the very beginning of incubation. 1 Pangenesis (pan, "all," or '^ the whole," and genesis^ '' origin " — that is, ''from the whole body") is the theory that the germ cells are built up by the streaming together, from all the organs of the body, of minute parti- cles (gemmules, or pangens) — an infolding or involution of the body into the germ. Then when a germ unfolds or develops, each pangen reproduces the part of the body from which it came. This theory implies an active influence of the body upon the germ plasm, and if parts of the body or brain should be specially developed by exercise or training, or if partfe or organs should be removed or lost by disease or accident, we should expect to find such additions or subtractions reproduced when the germs from such bodies developed. This we never find. There is no evidence that any acquired character is ever inherited. Lambs' tails have been bobbed for thousands of years, and lambs are born with tails as long as they ever were. Galton disproved pangenesis experimentally by exchanging the blood of animals. Since the blood is the only means by which the pangens could possibly circulate from the body to the reproductive cells, if we exchange blood between white and Jblack animals, we ought to get some of the pangens mixed. Galton's experiments disproved the theory absolutely, as does every case of budding and grafting. PKACTICAL LAWS OF LIFE 339 Germ plasm forms genu plasm and builds up tlie body, but the body cannot form or reproduce a single pangen or minutest particle of germ plasm. Organized study of genetics. What is your own community doing to improve its plants and animals? Many investi- gators and students in our universities and colleges, our ^ T looked about to iee nhat 1 comdfma amons our Hildin^S. The next tiling to do waS to fund tKe tesl and earlis5t grape for Seed and tnis 1 lound in | an accidental seedling at iKe foot of the luill . The crop j Mas atundant ripe in Augugl and of very good c|ual!ty | for a n'Jd grape. 1 ^owed \\\e Seed in the autunm of 1843. Among them the Concord Mas ^^^ only j one Horlhsavini?. Fig. 166. Quotation from Mr. Ephraim Bull on the wooden tablet marking the original Concord grapevine at Concord, Massachusetts Agricultural Department and experiment stations, practical seedsmen, farmers, and independent plant and animal breed- ers, are studying and experimenting and pushing discovery in this field. Invite local experts to visit the class and discuss their problems. Often by community cooperation better stock can be introduced than iany one member could afford, and its rapid increase insures enormous profits to such undertakings. Railroad companies and the International Harvester Company have agricultural experts who are helping along these lines. Hunt out stories of the discovery and introduction of new fruits, vegetables, grains, breeds of animals, and in the spirit 340 CIVIC BIOLOGY of these try to fiiid valuable variations in the neighborhood. Our native iiut trees have been neglected in this matter, and the Department of Agriculture is calling for a special search of the entire continent for valuable varieties. With the whole country organized for the search and with breeding in control of experts, we may hope for better progress in every line of plant and animal improvement than ever was known before. Injury of germ plasm. Germinal substance is, of course, obliged to draw its nourishment from the body; hence we may expect to find vigorous germs m strong, healthy bodies. Animals that become too fat are likely to have enfeebled germs or to be totally sterile, and conditions that show no appreciable injury to the body may prove fatal to the germ plasm. This is seen in Stockard's experiments with alcohol tabulated below: Experiments with (U inea Tigs to test Influence ok Alcohol ON Germ Cells Alcoholic Alcoholic males and normal females Normal males and alcoholic females Alcoholic males and alcoholic females Control Normal males and normal females Num- ber OF Mat- ing s Abor- tive Died AT Birth Live 7 5 (all runts) 2 ! 2 1 i 0 7 (all vigorous) The germ cell from each parent builds half the embryo, and the twenty-four matings in which the sperm alone is alcohol- ized are a proof that an alcoholized sperm cell of a guinea pig cannot do its share toward building up a normal offspring.^ 1 Stockard allowed the guinea pigs to breathe fumes of alcohol for one hour a day, six days in the week. The animals showed no outward injury, in fact they gained somewhat in weight. PRACTICAL LAWS OF LIFE 341 The following table shows similar results obtained by Hodge from carefully balanced experiments with selected dogs. The males were brothers and the females sisters from two unrelated litters of pedigree cocker spaniels. Demme's observations upon men are added for comparison. Infj.i'knoe of Alcohol on Pko (N> (n>- ®- 0- Martin Kallikak,'8r. d. 1837 Frederick Martin Kallikak, Jr When I am met by a proposition that is based on facts, and not on the ignoring of them, that is reasonable and convincing, and that is substantiated by the known laws of evidence and squares with common sense, I will embrace it. Otherwise, no ; and thank you all the same. Nothing doing on the esoteric, the fuzz-wuzzy, the ecstatic, the self- hypnotic, the what-if-it-is-true-after-all-you-can't-tell. My intelligence may be pretty poor, but it 's all I have. I'm going to stand by it and refuse to prostitute it, no matter what the bribe. The web of destiny is complex, I know, and none of us knows the secret springs of life and events; but I have a notion that if a man sticks to the truth as he sees it, and declines the lure of truth as he does not see it, even if the latter promises health, wealth, and a happy here- after, he will be likely to come out about where his Creator intended. ^ Using a library. The best investment any connnunity can make is to buy, catalogue, and keep up to date a library relating to its interests and industries ; and, in any modern sense of the word, that one is most efficiently educated who best knows how to use such a library. If our local and school libraries are properly managed and catalogued, it ought to be easy to find quickly all that is known on every subject discussed in this book. If every member of the class is col- lecting bulletins up to date and doing his share to help, 1 By Dr. Frank Crane, in the As.sociated Newspapers, 350 CIVIC BIOLOGY the laboratory bookshelf ought to be made to answer 95 per cent of the questions that arise. Individual pupils should also be gathering libraries relating to their own problems, interests, and projects. A really practical working method in using a library is of lifelong value to everyone. How many have acquired this at the end of their school or even college courses ? This is the one thing necessary to reason- ably intelligent modern living, and if many have failed to acquire .it in the course of their schooling, is it not because they have not had any real problems to solve that required such use of libraries ? Lincoln stated the case in a word when he said : ''A capacity and taste for reading gives access to whatever has already been discovered by others. It is the key, or one of the keys, to the already solved problems. And not only so: it gives a relish and facility for success- fully pursuing the unsolved ones " (p. 92). Catalogues, publication lists, and indexes. A library may be too poor to buy many books, but still be 100 per cent efficient if it keeps these indispensable helps in order and up to date. People can then find everything that has been written on any subject or by any author, and the local library can usually borrow from the state library or from that of their nearest university; or people might often buy books and donate them to their local library when they have finished with them. Every laboratory bookshelf must have for constant refer- ence the Monthly Lid of Publications (which is sent free to all who apply for it) and the Experiment Station Record J The first lists every bulletin of the central Department at Washington, as it appears, and the Experiment Station Record gives a well-annotated monthly bibliography of everything relating to the practical biology of agricultural advancement for the entire country and, in fact, for the world. Another 1 For both these publications address United States Department of Agri- culture, Washington, D.C. Subscription price of the Record is $1 a year. KNOWING HOW TO KNOW HOW 351 publication of the Department is the Weekly News Letter^ which contains brief, timely articles and notes. Some mem- ber of the class might subscribe for this and keep it in orderly file on the bookshelf. The question with which we started is, How can we get the best information most quickly? A concrete case will answer this question for thousands of similar problems. A botany class in a city was beginning the study of fungi, and in addition to the elementary book work each member was assigned an interesting fungus to work up and report upon. One of the boys, instead of the fungus assigned him, asked permission to take the black knot. The teacher was wise and honest enough to tell him that she knew nothing about it, but would be glad if he would learn all he could and give them all the benefit. He went to the library with a pack of postal cards and, going through the recent numbers of the Experiment Station Record, took down on the cards references to all likely articles on the black knot, addressed them, and within a week he had everything that everybody knew about the black knot. The boy then went to work out doors, hunted through the woods, and collected the fungus on native wild plums and cherries, and he made a survey of the city in order to form an intelligent estimate of the damage caused to cultivated fruits. He mounted a typical series of specimens in a glass case, all neatly labeled. He studied the fungus with the microscope and made careful drawings of all the important stages in its growth and reproduction. He drew colored wall charts from his pictures, supplemented by those in the books, and finally presented his results on the life history, distribution, and treatment of the black knot in a carefully prepared lecture which occupied an entire period of the class. One of his classmates happened to be a reporter on a local daily, and she presented the subject to the public in a well-written article of about two columns, and there followed such a cleaning up of black knot as that city had not seen in at least fourteen years. " What do you think about that work you did in school on the black knot ? " the boy was asked some years later. He replied, " It exactly fitted my bent, and on that account I think I got more real good out of it than from any other one thing in my high-school course." Better than all, this wholesome little try at real study quite probably helped him to decide what he wanted to do for the rest of his life. 352 CIVIC BIOLOGY Special organizations and journals. The science of our countiy and the world is not the dead, ciit-and-dried facts, "classified and arranged" in books. Real science has been de- fined as the "everlasting struggle of the human mind after the truth " (Lessing). Or, as Huxley put it, " Science is trained and organized common sense." In essence, science is the liv- ing, growing, forward-moving stream of discoveries — the best knowing liow that all the strugglers after truth are daily find- ing out. As long as there is progress it must always be that the best that someone is able to discover to-day will be ex- celled by the discoveries of to-morrow, and all that we know is but a handful of pebbles on the shore of the ocean of truth still to be discovered. Thus, in order to make sure that prog- ress in discovery shall never cease, men have organized univer- sities and research foundations and the scientific departments and bureaus of the state and national governments. In addition to the above are the many special associations of people drawn together by mutual interest in various prob- lems. These associations contain our best authorities on all sorts of subjects, and many of them publish special journals in which members first announce their discoveries. It niay be years before these discoveries find their way into the books of our libraries. Hence, if we are to find the best knowing how up to date, we should learn what these organizations are and keep track of the articles in their journals from month to month. We should first make a list of all local organizations pertinent to civic biology. Some of these may be branches of larger societies, national or international. As we learn about their purpose and work we should consider joining any that may seem desirable, and so begin to take our places in the organization of the community for progress. A few of the national organizations are indicated below : ^ 1 See Handbook of Learned Societies and Institutions of America, Carnegie Institution, Washington, D.C.. 1908, The World Almanac gives KXOWl^^a HOW TO KNOW HOW '66^ American Association for the Advancement of Science, Dr. L. O. Howard, permanent secretary, Washington, D.C., M^as founded in 1847 and lias 11,000 members. The biological sections are F, Zoology; G, Botany; K, Physiology and Experimental Medicine; and M, Agriculture. Sister organizations are the British and French associations for the advancement of science. The official organ is Science, published weekly, and sent gratis to all members in the United States as part return for the annual dues of p]. The Scientific Monthlji (continuation of the Popular Science Monthly) may be substituted if preferred. American Society of Naturalists was first organized in 1840 (reorganized in 1883) and is the parent from which many of the more special scientific societies have split off. It has 400 members. Central Association of Science and Mathematics Teachers (and many similar societies of science teachers). The official organ for all is School Science and Mathematics. American Nature Study Society, founded in 11)08; official organ, Nature-Study Revieiv, Ithaca, X.Y. American Public Health Association. The official organ, American Journal of Public Health, should be in every biological library. National Association for the Study and Prevention of Tuberculosis, founded in 1904, has about 2500 members and pub- lishes accounts of annual meetings. Society of American Bacteriologists, founded in 1899, limited to 75 members. American Association of Pathologists and Bacteriologists, founded in 1900. American Cancer Hesearc h Society, headipiarters, 1480 AVells Street, Chicago, 111. American Society of Zo()LOGists, founded in 1902, 187 members. Botanical Society of AxMerica, founded in 1898, has 496 mem- bers and publishes the American Journal of Botany. American Forestry Association, founded in 1882, has 15,000 members and publishes American Forestry, Washingix)n, D.C American Fisheries Society, organized in 1870, has 700 members. National Association of Audubon Societies, founded in 1905, now has about 4000 members, with branch societies in nearly every a list of learned societies, with dates of founding, number of members, addresses of some of the officers, and names of journals published, with their places of publication. Local libraries may supply more extended lists. 354 CIVIC BIOLOGY state. The official organ is Bird Lore, edited by Frank M. Chapman and published at Harrisburg, Pa. Amekican Ornithologists' Union, founded in 1883, has 1126 members, publishes the ^w^, the official journal of American ornithology, and also prints and keeps up to date the A. O. U. Check-List, giving the authoritative names, popular and scientific, of all birds of the United States. American Association of Economic Entomologists, founded in 1889, has about 500 members; official organ, Journal of Economic Ento- mology; Concord, N.H. A complete set of this journal ought to be accessible in every city and town library. American Entomological Society, founded in 1859, has 140 mem- bers and is devoted to purely systematic entomology. American Phytopathological Society. American Pomological Society, founded in 1849, has about 500 members and publishes biennial reports and special catalogues of fruits. American Society of Landscape Architects. American Genetic Association (continuation of the American Breeders Association), founded in 1903, has about 1200 members and publishes the Journal of Heredity, a monthly publication devoted to plant breeding, animal breeding, and eugenics. Washington, D.C. We have given dates of founding and number of mem- bers in order to emphasize the fact that organization for know- ing how to do things is only just beginning, and that as yet very few are actively concerned with these vital problems. CHAPTER XXXII PROGRESS IN DISCOVERY Anything which slieds light on the nature of life and of man himself, his organic constitution and equipment, the laws and possibilities of his mind and body, his place and fate in and relation to the rest of the universe, will appear immeasurably more important than the fate of individual men or nations, — because those things have a fundamental significance for the whole human race everywhere and for all time, and likewise have the deep- est sort of personal significance for everyone who is reflective enough to be conscious of the questions presented by his own being. The great battles of man have not been fought on Grecian plains or Spanish mains or over European hill and dale, but within the skulls of the great investigators, up and down the brain valleys and ridges of the great tliinkers and the immortal poets. It is the great captains of thought and feeling that have led forth the bright-shining forces of the human mind and soul in the only wars that have results of permanent and universal impor- tance,— wars in which thoughts, ideas, facts, conceptions are deployed and maneuvered in phalanxes and battalions to the greater issues of our human fate. Measured against such Himalayas of the human mind and soul as Darwin and Marx and Newton, Napoleon and Bismarck and Alexander are not even among the foothills of human significance. The publication of "The Origin of Species" was a more vital event in human history than the battle of Waterloo. — Courtney Lemon, Pearson^ s Magazine, February, 1917, p. 183 ff. I am impressed with the fact that the greatest thing a human soul ever does in this world is to see something and tell what it saw in a plain way. Hundreds of people can talk for one who can think, but • thousands can think for one who can see. To see clearly is poetry, philosophy and religion all in one. — Emerson y Beginning at home. What biological discoveries have you made ? Write down a list of them and tell in each case how you happened to make the discovery. Have you told anyone about them or published your discoveries so that 365 356 CIVIC BIOLOGY others may be helped or benefited by them ? How do you know that someone else has not discovered the same thing before you ? Has your father or mother, or some other member of 3^our family, discovered anything of value to the community ? Do you know of anyone in your town or city who has discovered anything? If so, can you find the story in print or can you go to the person and get the story at first hand ? Do we know of anyone hi the United States or Canada, South America, Europe, Asia, Australia, or Africa, who has made notable biological discoveries ?. Who is he, and what is the story of his work ? ^ Kinds of discoveries. Discoveries may be big or little ; they may be easy, made at a giauce, or even stumbled on by accident, though in this case one must be intelligent enough to know what he has found, and be able to think what his discovery may mean to the world (" Accidents never happen among the Hottentots," it is said) ; or they may require years of application, complicated apparatus, and costly laboratories. A little girl of eight, by working from daylight till dark, discovers that a bob white wdll eat 1286 rose slugs in a day, and that when fed abundantly on insects, she will lay eggs. These are valuable little discoveries and have doubtless influenced efforts to protect the bob- white. A young woman devotes three years to studying the foods of the bobwhite, and j)iiblislies what is probably the most complete statement of the food of any bird. This will exert still more influ- ence for bird protection and must hasten the day when we shall have enough bobwhites to reduce weed seeds and insect i)ests, and it may suggest to others similar studies of other birds.^ 1 As early as practicable, when the course is well begun and interest aroused, bring up these questions and make them the main subject of a lesson period ; or appoint a date and ask the class to prepare brief written statements in answer to the questions, and have them read and discussed. Invite some local discoverer to visit the class and tell of his aims, methods, and discoveries. 2 Margaret Morse Nice, ''Food of the Bobwhite." Journal of Economic Entomology, June, 1910, p. 295ff. PKOGKESS IN DISCO VEKV 357 lu 1816 Mrs. Isabella Gibbs discovered the Isabella grape, and this discovery is said to have turned attention to the culture of American grapes. Foui* years later Adlum discovered the Catawba. " A woman discovered it growing wild," and we have a vigorous new blackberry, the Blowers, added to the American list. Judge Logan discovers a chance seedling, and the Loganberry is saved to the world. ^Ir. Bull works a few years, and the Concord grape, and with it a new industry, is added to American horticulture. Mendel works eight years in his garden, and discovers his law of heredity. Jenner and Darwin each work twenty years, and the ideas of vaccination and the origin of species are placed at the service of mankind for all time. -" Importance. '' One single idea may have more value than all the labor of all the men, animals, and engines for a century^ Here are " mines," free to all alike, that dwarf our Kimber- leys, Nomes, and Klondikes to the small change of the passing hour, whose output is as much above gold and diamonds as mind is higher than matter. What kind of progress shall we make when all the people of the nation appreciate this point of view and begin to '' know enough to work together" in pushing forward needed discoveries ? We are approaching this degree of civic organization, as m evidenced by the growth of research departments in our uni- versities, by^ our experiment stations, and by the state and national scientific departments and the endowed private re- search foundations. All these are reaching down to search out talent, and ought to be inspiring every boy and girl to the most careful seeing and thinking of which they are capable. It is often said that Pasteur repaid to France the entire cost of her system of public education, from primary schools to university and from the beginning down to his time, by his one discovery of the cause and prevention of silkworm disease. So, as such values are being appreciated, the country and world are being searched for ability to discover. As its discoveries are the most priceless possessions of the race, and since advance in every field waits upon the discoverer 358 CIVIC BIOLOGY to lead the way, the scientific organization of the nation and of the world says, virtiiallyj to every young man and woman: " Shov) your mettle, demonstrate your ability to discover some- thing worth ivhile, and equipment and ynaterial support will he supplied, and every avenue of opportunity will he opened to you. Show poiver to think and to discover, and scholarships and fellowships are ready to place university apparatus and laboratories at your disposal Historical. How have discoveries been made in the past ? How have we learned to make two blades of grass grow where one grew before ? How may we make ten blades grow where one grows now ? What does it matter that we know the value of fresh air, of pure water, of good food; that we know that the blood circulates ; that we have brains and nerves and muscles which require exercise and care; and that we know about bacteria and parasites and the dis- eases they cause ? Do not these things, and all the rest for which the science of biology stands, mean the difference between a world of jungles and barren deserts, scourged by famines and pestilences, and a world of farms and gardens, full of happy, healthy people? Men have lived in the world for at least five hundred thousand years, and astronomers tell us that the earth will be habitable for about five million years to come. Is it not remarkable how little we know, how little all the millions and billions of men and women who have lived have been able to discover, — the handful of pebbles on the shore of the ocean of truth still to be discovered ? How incredibly slow progress in discovery must have been at first. How much do animals really " see " (in the sense in which Emerson uses the word) of the flowers and trees, birds, insects, and fungi in the fields they roam? And how little the best of us really see of all the things that happen in our fields, roadsides, and gardens. Without doubt thousands of choice varieties of flowers. PK0GRES8 IN DISCOVERY 359 grains, fruits, and nuts have lived and died out because no one saw the difference clearly enough to be able to think what they might mean to the world; and thousands more will go the same road until we learn to see and think civically. Our present-day discoverers. A number of names referred to in the text under various topics may be used for refer- ence. Our best authorities, as indicated in the preceding chapter, are often discoverers in their respective fields. They have probably won their positions by some creditable research work. Instead of trying to give a list of these it is better to gather the names as they appear as authors of our best books on birds, insects, forestry, agriculture, bacteria, health problems, and so on, or as they come to us from month to month in the biological journals or scientific bul- letins. We should be thankful to our discoverers for what they write, realizing that their work requires patient appli- cation and great sacrifice of time ; and while we follow their investigations in the libraries and journals, we should be very careful about encroaching upon their precious time by personal letters. Perhaps the most discouraging feature of our present situation is the overwhelming of our dis- coverer with inquiries by people who are too indolent to go to their libraries and read what he has written. For any special field we may have one or one hundred discoverers for our one hundred million people. Figure out about how much time it would take to answer a million letters. Biological discoverers. From the following brief list, or from any history of science or of medicine, let each member of the class choose some one discoverer, with whom he will become intimately acquainted during the remainder of the year. T^et him go to the biographies and histories and strive to catch the spirit that prompted the man to make his dis- coveries. Then, toward the close of the year, let each one 360 CIVIC BIOLOGY prepare a live-iniiiiite story to tell to the class. By timing these stories so that they follow in orderly sequence we may have the history of our science presented in an effective way. The aim is to kindle and foster the spirit of these men, so that increase in knowledge and progress in discovery may be assured from generation to generation. A number of names have been included for sake of completeness. The more im- portant and those especially interestmg on account of their contributions to civic biology are printed in black-faced type.^ 1.551 Gesner: gathered first botani- B.C. 540 500 460 400 350 320 320 300 A.D. 79 160 1542 1.548 Xenophanes : first to recog- nize fossils as proving that the earth was formed nnder the sea and rose out of it 1560 -Heraclitus: often called the 1583 first evolutionist ; he first advanced the principle, irdv- 1 590 ra pel (all things flow) Enipedocles : first to suggest 1603 natural selection and sur- vival of the fittest 1603 Hippocrates: called *' the Father of Medicine" 1622 Aristotle: founder of zoology Theophrastus : first botanist 1 ♦>49 Erasistratus "1 ^ „ , ., ^ first anatomists .^^^ Herophilus J . In-oO Pliny : wrote first popular nat- 1661 ural history Galen : founded medical physi- ology Vesalius : founder of modern anatomy 1667 Falloppio : anatomist cal garden (of fruits and flowers) and first zoological museum Eustachio : anatomist Csesalpinus: classified plants by fiowers Janssen, J. and Z. : discovered compound microscope Fabricius : discovered valves in the veins Harvey : discovered circulation of the blood Ascello : discovered the lac- teals Rudbeck : discovered the lym- phatics Swammerdam : first great stu- dent of insects in relation to plants and medicine Malpighi: discovered the capil- laries in the lungs ; founded modern embryology by a study of the incubation of the chick (1672) Leeuwenhoek : first to see bac- teria 1 Historical books to which the class should have access for this work are Locy, Biology and its Makers, New York, 1908 ; Baas, Outlines of the History of Medicine (translated by Handerson), New York, 1889 ; Mial, History of Biology, New York and London, 1911. PROGRESS ly DISCOVERY 361 1668 Redi : disproved spontaneous generation of insects by the discovery of eggs and 1704 larvae ; wrote '' Esperienze intorno alia Generazione degl' Insetti" 1670 Mayow : studied animal res- 1796 piration 1 796 1671 Hooke : worked out micro- scopical structure of plants 1800 1680 Borelli : proved that all the movements of animals are caused by muscles pulling 1801 on bone levers; wrote "De Motu Animalium " 1682 Grew : studied structure of plants 1693 Ray : classified plants 1801 1727 Hales: investigated respiration of plants 1743 Haller: father of modern physiology 1744 Reaumur: studied insects 1804 1749 Buffon : wrote a natural his- tory 1807 1 753 LinnjBus : classified plants 1761 Kolreuter: studied hybridiza- tion of plants 1811 1 76 1 Bonnet : evolutionist ; grouped animals in an ascending se- ries 1818 1772 Rutherford : discovered ni trogen 1823 1774 Priestley: discovered oxygen and studied the breathing of plants 1775 Spallanzani : disproved spon- taneous generation of bac- 1830 teria and molds and demon- 1835 strated presence of living 1838 germs in the air 1789 Galvani : discovered animal 1838 electricity 1790 Goethe: worked out a scheme for the metamorphosis of the parts of plants Darwin, Erasmus : grandfather of Charles Darwin ; wrote "Zoonomia," a long poem outlining evolution of life Jenner : discovered vaccination Sprengel : studied fertilization of plants Cuvier : studied comparative anatomy ; wrote " Le R6gne animal," 1817 Lamarck: invented a scheme for the evolution of animals (by conscious effort and in- heritance of acquired char- acters ; not proved) Treviranus : introdviced the name ''biology" as dis- tinguished from ''botany," ' ' zoology, " " physiology, ' ' "anatomy," etc. Humboldt : studied distribu- tion of plants Rumford, Count : demon- strated absorption of car- bonic acid by plants Bell, Charles : discovered mo- tor and sensory nerve roots ; founder of modern neurology G, St. Hilaire : pointed out unity of plan in animals Baer : discovered the law of embryological development (higher forms repeat the evolutionary series as the embiyos develop) Brown : described cell nucleus Dujardin : studied protoplasm Schleiden : discovered the cell as unit of structure in plants Schwann : discovered the cell as unit of structure in ani- mals 362 ' CIVIC BIOLOGY 1839 Agassiz : wrote on fresh-water fishes 1841 Helmholtz : discovered rate of nerve impulse 1853 Mohl : studied protoplasm (liv- ing substance) 1857 Pasteur : studied fermentation 1858 Darwin : reported his work upon the origin of species by natural selection 1858 Wallace : reported his work upon the origin of species by natural selection 1858 Virchow : worked out cellular pathology ; founder of mod- ern pathology 1863 Huxley: wrote "Evidence as to Man's Place in Nature" 1863 Lyell: wrote ''The Antiquity of Man" 1865 Sachs : studied structural bot- any 1865 Mendel: discovered the law of heredity 1867 Lister : worked out aseptic surgery 1875 Galton: studied inheritance 1875 1880 1880 1886 1893 1898 1888 1898 1898 1900 1900 1900 1903 1914 1915 Hertwig, O. : studied ferti- lization Koch : proved the relation of bacteria to disease Laveran : discovered malarial parasite (in the mosquito) Leuckart: settled the modern classification of animals ; specialized on parasites Weismann: studied germ-plasni Reed 1 discovered relation Finlay \- between yellow fever Lazear J and the mosquito Howard : discovered relation between typhoid fever and the house fly all, working inde- pendently, redis- covered Mendel's law of heredity Stiles : discovered hookworm in the United States Goddard : proved f eeble-mind- edness a unit character Stockard : discovered influence of alcohol on offspring De Vries Correns Tschermak INDEX Abalones, 273, 274 Acetic acid, 194 Actinidia arguta, 8S^ 90 Adder, 326 Aedes calopus, 124-128, 130, 132, 134, 154, 258 ; breeding places, 132 ; pictures of egg, larva, pupa, and adult, 124, 125; relation of, to yellow fever, 126, 127 Aerobic bacteria, 221 Agaricacece, 201-205 ; orders of, 204, 205 Agriculture, 91-106; breeding se- lected strains, 96-98; efficiency of, 93-96; fungous and bacterial diseases, 207-217; practical biol- ogy of, 91-106; problems of ani- mal industry, 102-104; relation of weeds to, 68 ; soil fertility, 98- 100 ; value of land, 100-102 Alcohol, 165, 191; influence of, on germ plasm, 340, 341, 343; manu- facture of, 194, 195 Alfalfa, 101, 212, 223 Algse, 188 Alkaloid, 201 Alligator, 321, 323 Alligator terrapin, 324 Almond, 165 Amanita, 73, 76, 200-205; descrip- tion and picture, 201, 202 American birds, orders of, 38-40, 42-51 ; pictures of, 22 American Bison Society, 171 American cockroach, 154 American crow, 48 American elm, 84 American false hellebore, 76 American goldfinch, 49 American goshawk, 45 American insects, 253 American laurel, 75 American lobster. See Lobster American lotus lily, 307 American magpie, 48 American mammals, 169-172 American osprey, 45 American redstart, 50 American robin, 51 Amphibia, 313-320, 325 Anaerobic bacteria, 221 Animal diseases, 110 Animal industry, 102-104 Animal parasites, 253-269 Anopheles, 127, 130, 131, 134, 154, 257 ; breeding places of, 132 ; pic- ture of eggs, larva, pupa, and adult of, 125; relation of, to ma- larial fever, 123, 124 Antelope, 169, 261 Anthracnose, 210, 212, 215 Anthrax, 235, 236, 248 Antimeningitis serum. 111 Antisepsis, 248 Antitoxins, 243, 247-249 Antivenins, 329 Ants, 141-147; carpenter ant, 146, 147 ; economic importance, 141 ; food, 143 ; rearing of, in labora- tory, 145-147 ; red ants, 155 ; spe- cial senses, 143 ; warfare, 144 ; white ants, 153, 155 363 364 CIVIC BIOLOGY Apanteles, enemies of, 140 Aphids, 61, 142, 152, 156 Apoplexy, 232 Apparatus, 11 Appendicitis, 234 Apple, 94, 165 Apple Day, 299 Apple of Peru, 75 Apple tree, blight of, 212, 213, 216 ; enemies of, 155, 156 Aquaria, 10, 315 ; cement for, 15 ; making of, 12-15 ; management of, 299-303 Aquatic duck foods, 307 Arachnids, problems of spiders, mites, and ticks, 163-168 Arbor Day, 299 Arbor vitae, 59, 165 Army worm, 156, 317 Arsenate of soda, 71 Arsenic, poison for rats, 180 Artesian wells, 219 Asepsis, 248 Asiatic poppy, 73 Asparagus beetle, 156 Asters, 86 Atlantic salmon, 309 Atlantic squid, 284 Australian duck-bill, 169 Bacteria, 176, 214; blight or wilt from, 215 ; control of bacterial diseases, 231-251 ; culture of, 224-230 ; distribution and forms of, 218 ; fungous and bacterial diseases of plants, 207-217; gen- eral discussion and treatment of, 186-191, 218-251 ; kinds of, 218, 220, 221, 234, 236, 242; labora- tory methods and experiments, 224-230; parasitic, 187; picturas of, 236; reproduction of, 220, 221; saprophytic, 221; size of, 218; symbiotic, 187, 221 ; venomous forms of, 234 ; work of, 221 Bacterins, 248 Badger, 171 Bald cypress, 59 Bald eagle, 45 Balsam, 59 Baltimore oriole, 48 Banana, food for mosquitoes, 131 Bank swallows, 49 Banostine Belle de Kol, 103 Barium carbonate, 179 Bark disease, 247 Barn swallows, 49 Barnacles, 287 Basket willow, 307 Basses, 309 Basswood, 59, 82 Bats, 129, 169 Bean blight, 215 Bear corn, 76 Bears, 165, 169 Beaver, 171, 172, 261 Bedbug, 154, 236 Beech, 59 Bees, 152, 153, 158; honeybee, 157 Beetles, 20, 21, 153-156, 317, 318 Belladonna, 73 Belted kingfisher, 46 Benzine, 165 Bindweed, 71 Biological library, 16, 17; using of , 349-351 Biology, instruction and research in, 346 Birch, 59, 83, 84 Bird Day, 299 Bird fountain, 29 Birds, 22-53, 313, 317 ; adaptation of, to environment, 37 ; attracting, 28, 31, 33; conservation of, 63; destruction of insects, 23, 24, 25 ; divisions of, 32 ; economic value INDEX 865 of, 24 ; food of, 24, 25, 30, 34, 42 ; food chart, 33; methods of bird study and special problems, 35- 53 ; migration, 29, 30, 31 ; number needed, 28 ; orders of, 22, 37-53 ; outdoor laboratory work, 25-31 ; plan of course, 23 ; topics for study, 31, 32 ; topography of, 37 ; winter feeding of, 31 ; work suggested, 31 Bison, 169, 171 Bitter rot, 210, 212, 213 Bittersweet, 76 Bivalves, 274 Black basses, 309 Black carpet beetle, 154 Black cherry, 59, 75 Black death, 175, 177, 233 Black flies, 113 Black gum, 59 Black knot, 207 Black mustard, 70 Black nightshade, 76 Black rot of cabbage, 212 Black snakes, 326 Black walnut, 59, 60, 82, 83 ; pictures of, 61, 66 Black-and-white warbler, 50 Blackberry, 94 Black-billed cuckoo, 46 Blackbirds, 34, 48 Blackleg, 248 Blight, on bean, 215 ; fire blight, 212 ; on pear and apple, 212, 213 ; on potato, 210, 215 Blister, or oil, beetle, 156 Blood, good and bad, 344 Blood-sucking conenose, 154 Blowfly, 154, 318 Blowing adder, 326 Blowing viper, 327 Blue crabs, 287, 292 Blue Jay, 48 Bhieback salmon, 309 Bluebird, 49, 51 Bluebottle, 112, 154 Bluegill, 299, 306, 307, 309 Blue-tailed lizard, 825 Bobolink, 48 Bob white, 34, 41, 42, 53, 332 Body louse, 154 Boils, 233, 234, 236, 248 Bollworm, 156 Bordeaux mixture, 209, 217 Borer beetle, 155 Botflies, 113, 157 Bovine malaria, 257 Bovine tuberculosis, 110, 223 Box tortoise, 324, 325 Bright' s disease, 232 Broad-leaf laurel, 75 Bronchitis, 234, 235 Bronzed grackle, 48 Brook trout, 309 Brooks's law, 291, 292, 808 ; applied to food and game fishes, 308 ; applied to the lobster problem, 286, 291, 292 Brown creeper, 51 Brown rot, 207, 210, 211 Brown thrasher, 51 Brown-tail moth, 20, 156, 160-162 Bubonic plague, 2, 107, 175-177, 215, 234, 248 Bugbane, 76 Bull thistle, 71 Bullfrogs, 313, 315, 316, 317, 319 Burdock, 71, 72 Burrowing rootstocks, 71 Butter clam, 278 Butterflies, 153; cabbage, 21, 136-140 Butternut, 59 Cabbage, 94, 98 ; black rot of, 212 Cabbage butterfly, 21, 136-140; con- trol, 138-140; dispersal, 137; fe- cundity, 136 ; life history, 136-137 ; natural enemies, 186 366 CIVIC BIOLOGY Cabbage caterpillar, 25 Cabbage looper, 166 Cabbage and radish maggot, 166 Cabbage worm, 156 Caddis flies, 153 Calcium, 98, 99, 100 Calcium chloride, 249 Calico bush, 75 Calico mosquito, 127 California poison sumac, 75 Camel, 261 ; itch mite of, 166 Campaign, anti-fly, 119, 120; anti- mosquito, 134, 135 Camphor tree, 73 Canada goose, 39 Canada thistle, 71 Cancer, 232, 234 Canker, 215 Cankerworm, 50, 51, 165 Cannas, 86 Caper spurge, 76 Carabid beetle, 317 Carbolic acid, 71, 249 Carbon, 98 Carbon bisulphide, used in destroy- ing rats, 181 Carbonic acid, 187, 191, 194, 195 Cardinal flower, 67, 154, 306, 307 Carpenter ant, directions for study of, 146, 147 Carpet beetle, 154 Carrot, 106 Casein, 189 Case-making moth, 154 Cases, insect-rearing, 10 Cashes, 76 Cat, 166, 182, 256, 263, 267 ; relation of, to diphtheria, 245, 246 Catbird, 61 Caterpillar, 46 Catfish, 306, 307, 309 Cattle, 171 Cattle tick, 167 Cedar, 83 Cedar wax wing, 50 Cephalopods, 274, 284 Cerebral hemorrhage, 232 Cerebrospinal meningitis, 248. See also Meningitis Cestodes, 260, 262 Chameleon, 325 Chara, 307 Cheese, Camembert, 189 ; Limburger, 189 ; Roquefort, 189 ; Stilton, 189 Cheese or ham skippers, 164 Cherry bird, 60 Cherry louse, 156 Chestnut, 69, 60, 82, 83 Chestnut-bark disease, 216 Chewink, 49 Chickadee, 60, 51 Chickens sick with limber neck, 122 Chicks killed by rats, 174 Chickweed, 70, 71 Chiggers, 165 Children's bane, 76 Chimney swift, 47 Chinchbug, 42, 156 Chinese pernicious scale, 156 Chinook salmon, 309 Chipping sparrow, 47, 49 Chlorine, 98, 114 Cholera, 107, 236, 236, 245, 248; fowl, 110, 233 ; hog, 110, 248 Cholera infantum, 20, 107 Cicadas, 153 Cinchona, 73 Citronella, 128 Civic biology, definition of, 1 ; plan of course, 3-9 Civic fly campaign, 119, 120 Civic forestry, 56-66 . Clam, 274 ; butter, 278 ; gaper, 278 ; giant, 278 ; hard, 273 ; life history of, 278, 279 ; little-neck, 277; razor, 273 ; soft, 273 ; surf, 273 INDEX 36' Cliff swallows, 49 Clothes moths, 154 Clover mite, 165 Cluster fly, 154 Clydesdales, 333 Coal oil, 71 Coast newt, 320 Cobra, 327 Cocaine, 343 Cockles, conchs of, 273 Cockroaches, 153, 154. See also Roaches Cod, 309 Codling moth, 21,155; type for study, 6 Coffee, 344 Cold, 233, 234, 246, 250, 251 Cold storage, 269 Coleoptera, 153 Collecting nets, 12 Colorado blue spruce, 83 Colorado potato beetle, 156 Common stramonium, 75 Conchs, 273, 274 Concord grapevine, 339 Condiments, 71 Conifers, 59 Consumption, 234 Contact infection, 246 Coontail, or hornwort, 307 Cooper's hawk, 45 Copepods, 287, 288, 289 Copperas, 114 Copperhead, 322, 327 Coral snake, 328 Corn, 93, 94, 95 Corn cockle, 75 Corn snake, 326 Corn-ear and tomato worm, 156 Corn-root aphis, 156 Corrosive sublimate, 249 Cotton, 93 ; pests of, 156 Cotton worm, 156 Cottonmouth, 327 Cottonwood, 59, 165 Cottony cushion scale, 20, 156 Cottony maple scale, 156 Couch grass, 71, 72 Cow, 102, 103, 165, 263 Cowbane, 75 Cowbird, 47, 48 Cowpox, 258 Cowslip, 306, 307 Crab, 287, 292-294 Crab apple, 82 Crappies, 306, 309 Crawfish, 287, 293, 294, 306, 307, 317, 318 Crested flycatcher, 47 Crickets, 153 Crimson Rambler rose, 97 Crocodiles, 321, 323 Crocus, 197 Crops, standards and percentage of efficiency of, 93, 96 Cross-pollination, 157, 158 Croton bug, 154 Croup, 232 Crown gall, 212, 216 Crows, 48 Crude drugs, 71, 73 Crude sulphuric acid, 71 Crustacea, 285-294, 315, 324 ; prod- ucts of, 287 Cuban pine, 59 Cuckoo, food of, 25, 46 Culex mosquito, 124, 125, 127, 128, 129,130,131,132; breeding places, 132 ; extermination of, 128 ; flight, 128 ; picture of eggs, larva, pupa, and adult, 129, 130 Curculio beetles, 155 Curled dock, 70, 71 Currant borer, 156 Currant worm or slug, 157 Cuttlefishes, 274 Cutworms, 25, 156, 317 368 CIVIC BIOLOGY Dahlia, 86 Dandelion, 72 Dandruff, 236 Darwin, Charles, 330, 331, 333, 338 Datura stramonium, 72, 75 Death-cup mushroom, 76 Death-of-man, 75 Deer, 169, 171, 172, 261, 263 Deer farming, 172 Deer flies, 113 Delaware grape, 85 Devilfishes, 274 Devil's apple, 75 Devil's-bite, 76 Diamond-backed terrapin, 324 Diarrhea, 232, 233, 234 Diphtheria, 177, 232, 234, 235, 236, 239, 243, 245, 246, 248, 250, 251 Diptera, 153, 155 Discoverers, biological, 359-362 ; present-day, 359 Discovery, history of, 358, 359 ; im- portance of, 357-358 ; kinds of, 356, 357 ; progress in, 355-362 Distemper, 248 Dock, 72 Dodder, 188 Dodo, 42, 43 Dog, 165, 182. 257, 263 ; influenceil by alcohol, 341 ; itch mite of, 166 ; as a transmitter of rabies, 256 Dog tick, 168 Dogwood, 75 Dourine, 259 Doves, 34, 42, 43 Downy woodpecker, 6, 46 Dragon flies, 129, 153 ; nymphs of, as enemies to young mosquitoes, 131 Drop, a disease of lettuce, 210 Drug plants, 72 Drug-store beetles, 155 Dry rot, or stem blight. 216 Duck, 38 ; attacked by rats, 174 Duck hawk, 45 Duck potato, or wapata, 307 Duckmeat (Lemna), 307 Duck-retter, 76 Dwarf larkspur, 76 Dysentery, 20, 107, 110, 233, 235, 245, 256 Eagle, 44 Earthworm, 25 Eczema, 236 Effluvia, 237 Egg record, 104 Egret, 40 Elderberry, 86 Elk, 169, 171 Elm, 59, 82-84, 165 Elm-leaf beetle, 21, 156 Elodea, 307 Endocarditis, 232 English sparrow, 45, 49, 50, 182 Enteritis, 107, 232, 234, 235. See also Gastro-enteritis Entomostraca, 287 Eohippus, 333 Erysipelas, 234, 251 Eugenics, 344 European root disease, 212 Evening primrose, 70 Evolution, 338 Excursions, plans for, 7, 8, 9 Facultative bacteria, 221 Fall webwonn, 155 Farm crops, relative fertility of, 101 Feeble-mindedness, causes and con- sequences of, 344 Felons, 233 Fence swift, 325 Fermentation, 191, 194, 195, 196 Ferns, 188 Field mice. 34. 44 INDEX 369 Field observations and records, 4, 5 Filariasis, 253 Filth-disease fly, 107 Filth-disease infections, 107, 110 Fire blight, 212 Fish hatchery made from tumbler, 303 Fish hawk, 45 Fish ponds on farms, 296 Fishes, 39, 306, 317; classification and species, 304 ; economic and civic value, 310 ; enemies of mos- quitoes, 131 ; habits and spawning seasons, 308 ; problems of fish and fishing, 295-311 Fishes Day, 299 Flat-headed apple-tree borer, 155 Flatworms, 255, 260 Flea, 182, ' 236, 240 ; burrowing (chigoe), 155 ; cat, 154 ; dog, 154 ; hen, 155 ; rat, 154 Flea beetle, 156 Flesh flies, 112 Flicker, 46 Flies, 107-122, 152,153, 182, 242, 245, 261, 268, 332 ; blood-sucking, 259 ; blowfly, 154, 318 ; bluebottles, 112, 154 ; botflies, 113, 157 ; campaigns against, 110, 111, 117, 118, 120, 122 ; cluster fly, 154 ; fecundity of, 117; fruit fly, 154 ; greenbottle, 112, 154; hibernation of, 117; hornfly, 113, 121, 157 ; kinds, 111, 112, 113, 118, 154, 318; life his- tory of, 116 ; nets for catching, 119 ; relation of, to disposal of waste, 114, 115 ; screens for, futil- ity of, 110 ; stable, 108, 109 ; traps for outdoors, 115, 118 ; tsetse, 236 ; work of, 107, 110 Flood plane, 56 Floods, cause of and damage from,' 55, 56 Flowering bean, 86 Flowering quince, 97 Flowers in relation to landscaping, 86 Flukes, 260 Flycatchers, 47 Fomites, 237, 238 Food, law of absorption, 189, 190 Foot-and-mouth disease, 110, 233, 256 Forest fires, causes of, 61, 64 ; dam- age from, 55, 62, 64; laws regulating, 66 ; relation of, to tree-planting, 65 Forest preserves, 171 Forestry, annual growth of trees, 55 ; consumption of wood, 55 ; effects of adequate planting, 57, 58 natural enemies of trees, 156 study of local problems of, 58 study of trees and civic viewpoint, 54-66 Formalin, as germicide, 249 ; use of, to prevent potato blight, 216 Formicary, 145 Foul brood, 233 Fowl cholera, 110, 233 Fowl tuberculosis, 110 Fox sparrow, 49 Foxglove, 78 Foxtail, 70 Fresh-water mussel, 273, 279, 281 Fringed gentian, 67 Frog, 39, 306, 313, 314, 315, 317, 318,' 320 ; possibilities of culture, 318 Fruit fly, 154 Fungi, 73, 97, 186-191; bacteria, general treatment of, 218-251 ; fungous and bacterial diseases of plants, 207-217; molds and mil- dews, 197-199; mushrooms, poi- sonous and edible, 200-206 ; yeasts, m-197 370 CIVIC BIOLOGY Fungous diseases, 207-213; damage from, 207 ; organizing for the con- trol of, 217 Fur farming, 172 Fur-bearing animals, 3 Gall insects, 157 Game, 3; killed by rats, 174 Game birds, 3 ; conservation of, 53 Gaper clam, 278 Gapeworm, 254, 266 Garden slug, 282, 283 Garden spurge, 76 Garter snake, 326 Gartered plume moth, 156 Gastro-enteritis, 111. See also Enter- itis Gastropods, 274, 282, 283, 284 Geese, 38, 53, 325 Genetics, 330, 337 ; organized study of, 339 Gentians, 67, 306 Geoduck, 278. See also Giant clam Geometrical increase, illustrated by diagram, 331 ; law of, 331-332 Germ plasm, 338 ; injury to, 340, 343 German roach, 154 Germicides, 248 Giant clam (geoduck), 278 Gila monster, 325 Ginseng, 73 Glanders, 235 Gnat catcher, 51 Gnats, 111, 153 Goat, 169, 261 ; itch mite of, 166 Golden plover, 40 Goldenrod, 86 Goldfinch, 49 Gonococcus infection, 240 Gonorrhea, 107 Gopher, 30, 34, 44 Gopher plant, 76 Gopher snake, 326 Gopher tortoise, 325 Goshawk, 45 Grackle, 48 Grain, pests of, 156 Grain aphis, or green bug, 156 Grape, 6, 85, 87, 88, 94 Grape-berry moth, 156 Grapevine root beetle, 156 Grasshoppers, 25, 152, 153, 156, 318 ; diagram of, 151 Great horned owl, 46 Great laurel, 76 Green frog, 315, 316 Green turtle, 324 Greenbottle fly, 112, 154 Grippe, 234, 236, 250, 251 Ground itch, 268 Grouse, 40 Grubb, 94 Guatemalan ant, 141 Guernsey, 103 Guinea pigs, experiments showing influence of alcohol upon, 340 Gull, 38 Gypsy moth, 20, 69, 148, 156, 159, 160, 162, 317 Hair snakes, 265 Hairy woodpecker, 46 Hard, or little-neck, clam, 277 Hardy perennials, 86 Hares, 165, 169 Harlequin snake, 328 Harvest mites, 163. 165 Harvestmen, 164 Hawks, 30, 34, 44, 45 Hawksbill, 324 Heath hen, 42 Heliotrope, 86' Hellebore, 76 Hemiptera, 153 Hemlock, 59, 75, 83 Hen. 104 INDEX 371 Hen flea, 155 Herbicides, 71 Herbs, 71, 73 Heredity, laws of, 330, 334, 338 Hermit thrush, 61 Heroin, 343 Heron, 39, 40 Herring gull, 38 Hessian fly, 21, 156 Hickory, 59, 60, 82 High laurel, 75 "Hill Folk, The," 345 Hip disease, 234 Hog and fowl cholera, 110, 233 Hollyhocks, 86 Holstein, 103 Honey locust, 82 Honeybee, 157; relation of, to tree fertility, 157 Hookworm, 107, 253, 254, 256, 268 Hookworm disease, 254, 268 ; pic- tures of victims of, 252 Horehound, 72 Horn fly, 113, 157 ; life history, 121 Horned lark, 48 Horned toad, 325 Horse, 165, 257, 261 ; itch mites of, 166 Horse botfly, 157 Horse-chestnut, 75 House ant, 155 House cricket, 154 House fly, 20, 317; breeding places, 113, 114 ; fecundity, 18 ; relation of, to filth, 116, 118. See also Flies House pets, 245 House wren, 51 ; food of, 25 Household insects, 154, 155 Hydrogen, 98 Hydrophobia, 256 Hymenoptera, 153, 156 Hypochlorites, 249, 251 Hypochlorous acid, 249 Human flea, 154 Human mite, 166 Human tapeworm, 260 Humming bird, 6, 46 Humming-bird moth, 155 Ichneumon fly, 136 Imported currant fly, 21 Indian corn, 95 Indian pipe, 188 Indian poke, 76 Indian-meal moth, 155 Indigo bunting, 49 Infantile paralysis, 20, 122, 236, 256 Infection, 110, 122, 246 Inflammation, 234, 236 Inflammatory fever, 248 Influenza, 235 Insect-catching bottle, 131 Insecticides, 152 Insectivorous birds, 44 Insects, 44, 51, 97, 176, 250, 253, 313, 315 ; attacking animals, 157 ; bene- ficial, 157 ; cases for mounting, 11 ; classification of, 150, 151, 152 ; damage and loss from, 19, 20, 24 ; fecundity of, 18 ; household, 154, 155 ; injurious to vegetation, 155, 156, 157; literature on, 149; nets for catching, 11, 12 ; orders of, 153; parts of, 152 ; size of, 18 ; work of, 18 ; work of controlling, 20 Ireland, famine in, 208 Iris, 86 Iron, 71, 98, 99 Ironwood, 59 Itch mites, 166 Itchweed, 76 Ivy, 75, 76 Ivy wood, 75 Jack pine, 59 JamCvStown lily, 75 372 CIVIC BIOLOGY Jamestown weed, 75 Japanese maple, 83 Japanese quince, 89 Japanese snowball, 89 Jays, 48 Jimson weed, 72, 75 Jukes family, 345 Junco, 49 June beetles, 153, 156 Kallikak family, diagram outlining history of, 342 Kalmia, 75 Kangaroo, 261 Kerosene, remedy for dog tick, 168 King cobra, 328 Kingbird, 47 Kingfisher, 46 Kinglets, 51 Kissing bug, 154 Laboratory, outfit of, 10 Laboratory work, outdoor, 25 Lace wings, 153 Lady beetle, 153; Chinese, 20-21 Lady's-slipper, 67 Lamb's-quarters, 69, 70 Lamellibranchs, 279 Lancaster elm, 78, 79, 80 Land, relative value of, 100, 101 Land salamander, 315 Land snail, 283 Landscape gardening, 77-90 Larch, 83 Larder beetles, 155 Lark, 34, 48 Larkspur, 76 Late blight, or rot, 216 Laurel, 75 Lawn, 71 Lead acetate, antidote for poison of ivy, oak, and sumac, 74 Leaf spot, 212 Leaf-eating sawfiies, 157 Least flycatcher, 47 Leghorn, w^hite, 104 Legumes, 188, 222 Lenma, 307 Leopard frog, 315, 316, 319 Leprosy, 107, 234, 251 Lettuce, 94 Library, using of, 349 Lice, 153, 154 Life, practical laws of, 330-345 Lilies, 86 Lily, 94 Limber neck, chickens sick with, 122 Lime, 99, 100, 102, 223 Lincoln, 92, 95 Linden, 82 Little black ant, 155 Little house fly, 112 Liver fluke, 261 Lizard, 321, 323, 325 Loblolly pine, 59 Lobster, 286-294 ; propagation, 289 Lockjaw, 234, 248 Loco weed, 73, 74 Locust, 59, 82 Loggerhead turtle, 324 Long-leaf pine, 59 Loons, 38 Louse, 154, 156 Lupus, 234 ' Li/coperdacem, 203 Lynxes, 160 Magnesium, 98, 99 Magpie, 48 Maidenhair fern, 67 Malaria, 20, 123, 124, 125, 134, 236, 252, 254 ; bovine, 257 ; prevention of, 133, 257 Malarial mosquito, 154 Malarial parasites, 256, 257 Mallard duck, 39, 306 IXDEX 378 Mammals, 34, 167, 176 ; American Mammal Problems, 169-172 ; orders of, with pictures of habi- tats, 170 Man, 176 Manganese, 98 Manure, barnyard, 70 ; disposal of, 115 ; relation of, to flies, 114, 115 Maples, 59, 88 Marigold, 86 Markweed, 75 Marsh hawk, 45 Marsh wren, 51 Martin, 49, 171 Massasaugas, 327 Mayweed, 70 Meadow lark, 48 Meal worm, 155 Measles, 36, 215, 232. 283, 236, 239, 247, 256 Medicinal plants, 71 Mendel's law, 330, 337, 344, 345; diagram illustrating, 335, 338 ; history of, 336 Meningitis, 107, 234. See also Cere- brospinal meningitis Meningococcus, 234 Mercuric acid, cure for potato scab, 216 Mercuric chloride, 240 Mercury, 75 Miasms, 237 Mice, 30, 34, 44, 174. 182. 183, 184, 185, 245, 267 Mildew. See Molds Milk, pasteurizing of, 244 Milkweed, 69, 71 Minks, 169 Mission grape, 85 Mites, 163-168, 236; clover mite, ' 65 ; harvest mite, 163, 165 ; itch • lite, 166 ; poultry mite, 167; red V aite, 129 ; sheep-scab mite, 166 Moccasins, 327, 328 Mocking bird, 50, 51 Molds and mildews, 97, 186, 189, 191, 193, 194, 210 ; botanical position and structure of, 197, 198 ; obser- vation of and experiments with, 199 Mole plant, 76 Moles, 30, 165, 171 Mollusca, classification of, 274 Mollusks, 271-284 Mongolian, or ring-necked, pheasant, 42 Monkey, 263 Moose, 169 Morphine, 343 Mosquito, 20, 111, 113, 119, 123-135. 153, 154, 164, 182, 236, 240, 253, 257, 332 ; breeding places of, 131, 132 ; kinds of, 125 ; life history of, 124, 128 ; methods of extermi- nation of, 133 ; natural enemies of, 129, 131 ; planning of cam- paign against, 134, 135 Mosses, 188 Moth, 153, 318 ; case-making, 154 ; clothes, 154 ; codling, 6, 155. See also Brown-tail moth. Grape-berry moth, Gypsy moth, White-marked tussock moth Mountain laurel, 75, 86 Mountain sheep, 169 Mourning dove, 43, 44 Mucket shells, 307 Mud, or pond, terrapins, 325 Mud puppies, 314, 320 Mulberry, o9 Mullein, 71, 72 Mumps, 247 Mushrooms, 73, 186, 189, 197, 210 ; cause of root rot, 211 ; classifica- tion of, 203-206 ; poisonous and edible, 200-206 Musk grass (Charu), 307 374 CIVIC BIOLOGY Muskrat, 171 Muskrat weed, 75 Musquash root, 76 Mussels, 273, 274, 279-281, 300 Mustard, 70, 72 Mutation, 338 Myriapods, 317 Myriophyllum, 307 Mytilus, 276, 277, 278, 279 Nagana, or tsetse-fly disease, 259 Nam family, 345 Nasturtium, 86 Native plants, conservation of, 67 Natural selection, law of, 335 Nautilus, 274 Nematodes, 264, 265, 266 NephriMs, 232 Nets, collecting, 11 ; fly, 119 ; ma- terials for making, 12 Neuroptera, 153 Newts, 131, 314, 320 Nicotine, 343 Niggerhead, 280 Nighthawk, 47 Nightshade, 76 Nitrates, 102 Nitrifying bacteria, 222 Nitrogen, 47, 98-101, 187 Norman Percherons, 333 Notebook, instructions for keeping, in field and laboratory, 11 Noxious mammals, 30, 44 ; destruc- tion of, 44 Nuthatches, 51 Nuts, importance of, and suggestions for growing, 60 Oak, 69, 83, 84 Oats, 93 Octopus, 274 Oil, coal, 71 ; olive, 128 ; of tar, 128 Onion maggot, 156 Ophthalmia, 107 Opium, 343 Opsonic index, 248 Orchard orioles, food of, 25 Orchard pests, 155 Oregon water hemlock, 76 Oriental cockroach, 154 Orioles, 48 Orthoptera, 153 Osprey, 45 Otter, 171 Ovenbird, 50 Owls, 30, 34, 44 Oxygen, 98, 194 Oyster, 271, 274, 279; Atlantic, 273 ; Pacific, 273 ; producing sickness. 272 Oyster drill, 282 Oyster-shell scale, 166, 332 Pacific clam, 278 Pacific crab, 292 Painted tortoise, 326 Pangenesis, 338 Panther, 169 Parasites, use of, to control insects, 161 Parasitic bacteria, 221 Parasitic protozoa, 266 Parasitic worms, 107 Parsnips, 105 Passenger pigeon, 36, 43, 44 ; egg of, 43 ; picture of, 36 Pasteur, 196, 209 Pavement ant, 156 Peach, 94, 165 Peach yellows, 214, 215 Peach-tree borer, 156 Pear, 94 Pear and apple blight, 212, 213, 216 Pear slug, 157 Pear-blight beetle, 155 Pearl fishing, 279, 280 I INDEX 375 Pear-tree borer, 155 Pecau, 00 Peeper, 31 « Pellagra, 113, 251 Pennyroyal, 128 Peonies, 86 Pepper biuli, 80 Peppergra«s, 70, 71 Perch, 306 Perennial crown«, 71 PeriUjnitis, 234 Periwinkle, 274 llieasants, 40 Phenol, coefficient of, 249 Phloxes, 86 Phoebe, 47 ; food of, 25 Phosphates, 223 Phosphorus, 96, 98, 99, 100, 101; used for poisoning rats, 181 Pickerel frog, 315, 316, 319 Pied-billed grebe, 38 Pig, 201 ; as host for trichina wonn, 267 ; itch mites of, 166 ; tapeworm of, 263 Pigeon, 35, 36, 42; killed by rats, 174; kinds of: band-tailed pigeon, 43 ; passenger pigeon, 43 ; red- billed pige^jn, 43 ; Viosca's pigeon, 43 Pigeon grass, 70 Pigeon hawk, 45 Pigweed, 09, 70 Pimples, 248 Pine, 59, 83, 84 ; white pine, study of, 4, 5, 0 Pintail, 39 Pinworrn, 266 Piroplasmas, 257, 268 Pitch pine, 59 Plague, 236 Plankton, 219 Plant food, essential elements of, 99 ; losses in, due to cropping, 102 Plant lice, 153, 150, 104 ; fecundity of, 18 J:*lant problems, 07-76*; conservation of native plants,. 67 Plantain, 71 Plover, 40 Plum, 165 Plymouth Rock, 104 Pneumococcus, 234 Pneumonia, 121, 184, 232-236, 248, 250, 251 Poison ash, 75 Poison elder, 75 Poison hemlock, 72, 75 Poison ivy, 74, 75 Poison laurel, 75 Poison oak, 74, 75 Poison root, 75 Poison snakeweed, 75 Poison sumac, 74, 75 Poisonous plants, damage from, 73 ; list of, 75, 76 Poisonous snakes, 110, 327-329 Pokeroot, 76 Poke weed, 75 Poliomyelitis, 122 Ponds, as balanced aquaria, 304 ; possible production from. 307 Poplar, 105 Porpoises, 109 Potash, 102, 223 Potassium, 90, 98, 99, 100, 101 Potat^j, 93, 97; blight or scab of, 210, 215 Potato beetles, 42, 153 Poultry, 103, 104 Poultry mite, 167 Pout, 306 'Prairie chicken, 63 Prawns, 287 Proteans, 313 Protein, 187, 189 Protozoa, 266, 25Cf 376 CIVIC BIOLOGY Puerperai fever, 234 Puff balls, 189, 191, 203, 206 Pulmonary tu"berculosis, 249 Purple beech, 83 Purple cornflower, 73 Purple flnch, 49 I'urple niartin, 49 Purslane, 69, 70 Quack grass, 72 Rabbit, 169, 261 Rabid dogs, 110 Rabies, 248, 256 Ragweed, 70 Railroad worm, 156 Rainbow trout, 309 Raspberry, 94 Rat snake, 326 Rats, 30, 34, 44, 245, 267, 332; damage from, 2, 174, 175, 176; extermination of, 3, 177-184; fecundity of, 2, 173; poisoning of, 179, 180, 181 ; problem of, 173-185; trapping of, 177, 178, 179, 182, 184, 185 Rattlebox, 76 Rattlesnake, 253, 322, 327, 328 Red ant, 155 Red buckeye, 75 Red cedar, 59 Red gum, 59 Red mite, 129 Red pepper, 73 Red pine, 59 Red spider, 163, 164 Red-backed salamander, 316 , Red-eyed vireo, 50 Red-headed woodpecker, 4(> lied-lnnuped apple-tree caterpilhii', 15(5 Red-legged locust, 15(5 Red-shouldered hawk, 44, 45 Redstart, 50 Red-tailed hawk, 45 Red-winged blackbird, 48 Reptiles, 321-329 ; products of, 321, 323 Rheumatism, 233, 234, 236 Rhinitis, 234, 235 Rhizopus, 198 Rhododendron, 76 Roaches, 245. See also Cockroaches Robin, 51 Rock bass, 306 Rock pine, 59 Rocky Mountain spotted-fever tick, 167 Rodents, 326 Root gall, 212 Root knot, 265 Root rot, 211, 212 Root tubercles, 188 Bosa rugosa, 89, 97 Rose, 86, 94, 97 Rose chafer, 156 Rose slug, 157 Rose-breasted grosbeak, 49 Round-headed apple-tree; borer, 155 Roundworms, 264, 265, 266 Ruby-crowned kinglet, 51 Ruby-throated hunnning bird, 47 Ruffed grouse, 41, 42, 52, 53 Rum cherry, 75 Rust, 186, 207, 210, 212 Sable, 171 Saccharomycetes, 191 Salamanders, 313, 316, 319, 320, 325 ; enemies of mosquitoes, 131 Salmon, 309, 310, 311 San Jos^ scale, 20, (59, 152, 156, 158, 332; fecundity of, 18 Sand flies, 113 Saprolegnia, 305 Saprophytic bacteria, 221 TNl^EX 377 Sapsucker, 46 Sawflies, 153 Sayornis phoebe, 47 Scab, on apple, 212 ; on potato, 210 Scale insects, 153, 156 Scallops, 273, 274, 277 Scarletfever, 177, 232, 233, 236,239, 243, 245, 246, 247, 251, 256 Scarlet tanager, 25, 49 Schick reaction, 251 Scientific organizations, journals of, 352, 353, 354 Scorpion, 163, 164 Screech owl, 45 Screens, cost of, 20 Screw-worm fly, 113, 157 Scrub pine, 59 Scurvy scale, 156 Sea mussels, 271, 272, 273, 275; pic- ture of beds of, 270 Seed, 188 Selection and survival of the fittest, 330 Seneca snakeroot, 73 Septicaemia, 234 Serum, 248; antitoxic sera for snake poisons (antivenins), 329 ; Flexner's anti meningitis. 111 ; re- sistance of, 249 Shad, 296, 309, 310, 311 Sliagbark hickory, 82 Sharp-shinned hawk, 45 Sheep, 257, 263; itch mite of, 166; liver fluke in, 261 Sheep botfly, 157 Sheep laurel, 75 Sheep-scab mite, 163, 166 Shepherd's-purse, 70, 71 Shetland ponies, 333 Shore bird, 40 Short-leaf pine, 59 Shrikes, 30, 34, 50 Shrubs, 84, 86 Silicon, 98 Silver fox, 172 Sirens, 313, 314 Sistrurus, 327 Skink, 325 Skunk, 169, 256 Sleeping sickness, 236 Slug, currant, 157; pear, 157 ; rose, 157 Slugs, 282, 283, 315; eaten by box tortoise, 325 Small laurel, 75 Smallpox, 107, 211, 233, 236, 237, 247, 251, 256 ; control of, by vacci- nation, 258, 259 Smartweed, 70 Smuts, 186, 207, 210 ; on corn, 213, 216 ; on oats, 212 Snails, 274, 283 Snake venom, treatment of, 329 Snakes, 40, 321, 323; number of species of, 326 ; poisonous, 110, 327-328 Snakeweed, 75 Snapping terrapin, 324 Sneezeweed, 76 Snowball, 97 Snow-on-the-mountain, 76 Society for the Protection of Native Plants, 67 Sodium, 98 Sodium chloride, 249 Sodium hypochlorite, 249 Soft, or long-necked, clam, 276, 278 Soft-shelled terrapin, 325 Soil, effects of washing on, 57 ; ele- ments in, 99 ; fertility of, 91, 98 ; loss of fertility of, 55, 102 Song birds killed by rats, 174 Song sparrow, 49 Sonoran coral snake, 328 Sorghum, 197 Sourwood, 59 378 CIVIC BIOLOGY Southern clothes moth, 154 Sow bug, 317 Sparrow, 34, 45, 47, 49, 50, 182 Sparrow hawk, 45 Sphinx moth, 155, 156 Spidei-s, 46, 51, 163-168, 315 Spinal meningitis, 107, 110 Spirilla, 218 Spirits of camphor, 128 Spitzenburg apple, 334 Spoonwood, 75 Spotted cowbane, 75 Spotted fever, 233, 236, 256 Spotted parsley, 75 Spotted salamander, 316 Spotted sandpiper, 40 Spotted terrapin, 325 SpiTice pine, 59 Spruces, 58, 83 Squash bug, 152, 156 Squids, 273, 274 Squirrel, 261 Stable fly, 20, 113, 121, 122, 154, 236 ; life history of, 121 Stable-window fly trap, 108, 109 Staggerbush, 76 Staggerweed, 76 Staphylococci, 234 Stegomyia fasciata, 258 Stewart's disease, 215 Sticktights, 69 Stinkhorns, 204 Stinking smut, 213 Stinkweed, 75 Stinkwort, 75 Stork, 39 Strains, pure-bred selected, 96, 97 Strawberry, 94 ; enemies of, 156 Streptococcus, 234 Striped cucumber beetle, 156 Strychnia sulphate, 181 Strychnine used for poisoning rats, 180, 181 Sugar, danger from gorging with, 344 Sugar, or rock, maple, 82 Sugar pine, 59 Sulphate of copper, 71 Sulphur, 98, 99 Sulphur ointment, 165 Sumac, 74, 75, 86 Summer cholera. See Summer com- plaint Summer complaint, 107, 110, 121 Sunfish, 306 Sunflower, 86 Surra, 259 Swallows, 49, 129 Swamp hellebore, 76 Swamp sumac, 75 Swan, 38, 42 Swatter, 119 Sweet peas, 86 Swine, 174 Sycamore, 59 Symbiotic bacteria, 221 Syphilis, 107 Syrphus flies, 112 Tachina flies, 112 Tadpoles, 314-318 Tamarack, 59 Tanagers, 49 Tansy, 72 Tapestry moths, 154 Tapeworm, 107, 254, 260, 262-264 ; of dogs, 264; of fishes, 264; of man, 261 Tarantulas, 164 Tea, 344 Teal, 306 Teasel, 71 Tent caterpillar, 155 Termites, 155 Terns, 38 Terrapins, 321, 323, 324, 325 INDEX 379 Tetanus, 248 Texas fever, 97, 163, 167, 168, 236, 267 Thorn apple, 75 Thrashers, 50 Threadworms, 255, 264 Three-leaved ivy, 75 Thrushes, 51 Thunderwood, 75 Ticks, 163, 164, 165, 236, 255 ; cattle tick, 167, 168, 257 ; dog, or wood, tick, 168 ; Rocky Mountain, or spotted-fever, tick, 167 ; species of, 168 Titmice, 51 Toads, 306, 312-320; commercial value of, 317; eggs and tadpoles, 314-316, 318; food and feeding tests, 312, 315, 317 Tobacco as an insecticide, 114, 343 Tomato, 94 Tonsillitis, 233, 234, 235, 243, 245, 251 Tools, 13, 14 Toothache, 233 Tortoises, 321, 324, 325 Towhee, 49 Trailing arbutus, 67 Tree frogs, 313, 314-, 316, 319, 320 Tree sparrows, 34, 49 Tree swallows, 49 Trees, characters of, 82 ; hard woods, 59 ; light demanders, 59 ; planting of, 61 ; relation of, to landscaping, 81, 83,84 ; shadebearers, 59 ; study of, 59, 60 Trematodes, 260 Trichina, 175, 266, 267, 268 Trichinosis, 264, 266 Trout, 309 Trumpeter swan, 39 Truth, fake sources of, 347 Trypanosomes, 259, 260 Tsetse flies, 236, 259, 260 Tuberculosis, 107, 110, 121, 232, 234, 235, 236, 245, 250, 251, 252, 256 ; avian, 233 ; bovine, 110, 233 ; pul- monary, 249 Tuberoses, 86 Tubers, 71, 307 Turkeys killed by rats, 174 Turpentine a remedy for dog tick, 168 Turtles, 131, 321, 323, 325 Typhlitis, 234 Typhoid, 20, 110, 118, 121, 177, 232, 234, 235, 236, 242, 243, 245, 248, 251 ; epidemic of, 241 ; relation of dirty hands to, 250 Typhoid fly, 107, 112 ; life history of, 113. See also House fly Typhoid Mary, 242 Typhus fever, 236, 256 Uncinariasis, 268 Vaccination, 258 Vaccines, 248 Van Fleet rose, 97 Variation, 330, 338 ; law of, 333 Vedalia beetle, 20 Vegetables, pests of, 156 Venomous snakes, 324 Vermin, 245 Vinegar eels, 265 Vines, 87 ; relation of, to landscape gardening, 87, 88, 89 Viosca's pigeon, 43 Viper, 327 Vireos, 48, 50 Virginia scrub pine, 59 Vivaria, 10, 131 Walking sticks, 153 Walnut. See Black walnut Wapata, 307 Warblers, 48, 50 380 CIVIC BIOLOGY Warbling vireo, 50 Wasps, 153 Water beetles, larva? of, 131 Water bugs, 153 Water cress, 306, 307 Water hemlock, 73, 75 Water lilies, 306, 307 Water snakes, 326 Waterfowl, 38, 39, 40, 45, 324 Waxwings, 50 Weasels, 169 Weeds, 67-76 ; adaptability of, 70 ; classes of, 70, 71 ; damage from, 68 ; destruction and control of, 34, 69, 71 ; medicinal, 71, 72 Weeping willow, 84 Weevils, 155, 156, 317 Western little-neck clam, 278 Western prairie chicken, 42 Whale, 169 Wheat, 93, 94, 95, 97 Whippoorwill, 47, 129 Whistling swan, 39 White ants, 153, 155 White ash, 82 White cedar, 59 White diarrhea of chicks, 233 White elm, 59 White hellebore, 76 White man's plant, 75 White pine, 59, 84 ; type for study, 4, 5, 6 White-breasted nuthatch, 51 Whitefish, 309 White-marked tussock moth, 156 White-throated sparrow, 49 Whooping cough, 232, 234, 247 Wicky, 75 Widal reaction, 251 Wild boar, 263 Wild carrot, 71 Wild cat, 169 Wild celery, 307 Wild cherry, 75 Wild duck, 53, 325 Wild onion, 71 Wild rice, 307 Wild rose, 86 Wild sago, 307 Wild trout, 305 Wild turkey, 42, 53 Willow, 59, 307 Wilson snipe, 40 Wilson's thrush, 51 Wilt disease, 212 ; bacterial blight, 215 ; stem blight, 216 Window flytrap, 108, 109 Wode-whistle, 75 Wolf, 169, 256 ; itch mite of, 166 Wolfsbane, 76 Wolf s-milk, 76 Wolverine, 169 Wood duck, 39, 40, 306, 307 Wood frog, 315, 316, 319 Wood laurel, 75 Wood pewee, food of, 24, 47 Wood thrush, 51 Wood ticks, 165, 168 AVoodcock, 40 Woodpecker, 7, 46 Woolly apple louse, 156 Woolly loco weed, 76 Worms, 51, 315 Wormseed, 69 AVrens, 50 Yeara, 75 Yeast, 186, 189-197 ; a cause of dis- ease, 197 ; description of, 191, 192 ; distribution of, 192 ; pure culture of, 195 ; uses of, 194 Yellow fever, 20, 123, 124, 126, 134, 233, 236, 240, 253, 254, 256, 258 Yellow perch, 309 ; topography of, 298 Yellow pine, 59 INDEX 381 Yellow poplar, 61) Yellow-throated vireo, 50 Yellow warbler, 50 Yellow woolly bear, 155 Zero family, 345 Yellow-billed cuckoo, 40 Zinnias, 86 Yellow-fever mosquito, 124, 125 Zoological parks, 171 THIS BOOK IS DUE ON THE LAST DATE STAMPED BELOW AN INITIAL FINE OF 25 CENTS WILL BE ASSESSED FOR FAILURE TO RETURN THIS BOOK ON THE DATE DUE. THE PENALTY WILL INCREASE TO 50 CENTS ON THE FOURTH DAY AND TO $1.00 ON THE SEVENTH DAY OVERDUE. Q.HJ05 KG. UNIVERSITY OF CAUFORNIA UBRARY