This little book is an attempt to bring together and place in untechnical form the most important of these facts gathered from sources many of which are at present inaccessible to the general reader, perhaps even to many physicians and entomologists.
In order that the reader who is not a specialist in medicine or entomology may more readily understand the intimate biological relations of the animals and parasites to be discussed it seems desirable to call attention first to their systematic relations and to review some of the important general facts in regard to their structure and life-history. This, it is believed, will make even the most complex special interrelations of some of these organisms readily understandable by all. Those who are already more or less familiar with these things may find the bibliography of use for more extended reading.
My thanks are due to Prof. V.L. Kellogg for reading the manuscript and offering helpful suggestions and criticisms.
Unless otherwise credited the pictures are from photographs taken by the author in the laboratory and field. As many of these are pictures of live specimens it is believed that they will be of interest as showing the insects, not as we think they should be, but as they actually are. Mr. J.H. Paine has given me valuable aid in preparing these photographs.
R.W.D.
Stanford University, California,
March, 1910.
CONTENTS
| [CHAPTER I] | |
| PAGE | |
| Parasitism and Disease | 1 |
Definition of a parasite, 1; examples among various animals,2; Parasitism, 3; effect on the parasite, 4; how a harmlesskind may become harmful, 5; immunity, 6; Diseases caused byparasites, 7; ancient and modern views, 7; Infectious and contagiousdiseases, 8; examples, 9; importance of distinguishing,9; Effect of the parasite on the host, 9; microbes everywhere, 10;importance of size, 11; numbers, 11; location, 11; mechanicalinjury, 12; morphological injury, 13; physiological effect, 13;the point of view, 14. | |
| [CHAPTER II] | |
| Bacteria and Protozoa | 15 |
Bacteria, 15; border line between plants and animals, 15;most bacteria not harmful, 15; a few cause disease, 15; howthey multiply, 15; parasitic and non-parasitic kinds, 17; how akind normally harmless may become harmful, 18; effect of thebacteria on the host, 18; methods of dissemination, 18; Protozoa,19; Amœba, 19; its lack of special organs, 19; whereit lives, 19; growth and reproduction, 19; Classes of Protozoa,20; the amœba-like forms, 20; the flagellate forms, 20; importanceof these, 21; the ciliated forms, 22; the Sporozoa orspore-forming kinds, 22; these most important, 23; abundance,23; adaptability, 23; common characters, 24; ability toresist unfavorable conditions, 24. | |
| [CHAPTER III] | |
| Ticks and Mites | 26 |
Ticks, 26; general characters, 27; mouth-parts, 27; habits,27; life-history, 27; Ticks and disease, 28; Texas fever, 28; itsoccurrence in the north, 28; carried by a tick, 29; loss andmethods of control, 31; other diseases of cattle carried by ticks,31; Rocky Mountain spotted fever, 32; its occurrence, 32;probably caused by parasites, 32; relation of ticks to this disease,33; Relapsing Fever, 33; its occurrence, 34; transmittedby ticks, 34; Mites, 35; Face-mites, 35; Itch-mites, 36; Harvest-mites, 37. | |
| [CHAPTER IV] | |
| How Insects Cause or Carry Disease | 40 |
Numbers, 40; importance, 41; losses caused by insects, 41;loss of life, 42; The flies, 43; horse-flies, 43; stable-flies, 44;surra, 45; nagana, 45; black-flies, 46; punkies, 46; screw-wormflies, 47; blow-flies, 48; flesh-flies, 48; fly larvæ in intestinalcanal, 49; bot-flies, 50; Fleas, 52; jigger-flea, 53; Bedbugs, 54;Lice, 54; How insects may carry disease, 55; in a mechanicalway, 55; as one of the necessary hosts of the parasite, 56. | |
| [CHAPTER V] | |
| House-flies or Typhoid-flies | 57 |
The old attitude toward the house-fly, 57; its present standing,58; reasons for the change, 58; Structure, 59; head andmouth-parts, 60; thorax and wings, 61; feet, 62; How theycarry bacteria, 62; Life-history, 63; eggs, 63; ordinarily laid inmanure, 63; other places, 63; habits of the larvæ, 64; habits ofthe adults, 64; places they visit, 65; Flies and typhoid, 65;patients carrying the germs before and after they have had thedisease, 65; how the flies get these on their body and distributethem, 66; results of some observations and experiments, 66;Flies and other diseases, 68; flies and cholera, 68; flies and tuberculosis,69; possibility of their carrying other diseases, 70;Fighting flies, 71; screens not sufficient, 71; the larger problem,71; the manure pile, 72; outdoor privies, 72; garbage can,72; coöperation necessary, 72; city ordinances, 73; an expert'sopinion of the house-fly, 73; Other flies, 75; habits of severalmuch the same but do not enter house as much, 75; the smallhouse-fly, 75; stable-flies, 75; these may spread disease, 75. | |
| [CHAPTER VI] | |
| Mosquitoes | 76 |
Numbers, 76; interest and importance, 76; eggs, 77; alwaysin water, 77; time of hatching, 77; Larvæ, 78; live only in water,78; head and mouth-parts of larvæ, 78; what they feed on,78; breathing apparatus, 79; growth of the larvæ, 80; Pupæ,80; active but takes no food, 80; breathing tubes, 80; how theadult issues, 81; The Adult, 81; male and female, 81; how mosquitoes"sing" and how the song is heard, 82; the palpi, 82;The Mouth-parts, 83; needles for piercing, 83; How the mosquitobites, 84; secretion from the salivary gland, 84; why malescannot bite, 84; blood not necessary for either sex, 84; TheThorax, 85; the legs, 85; the wings, 85; the balancers, 85; thebreathing pores, 86; The abdomen, 86; The digestive system,86; The salivary glands, 87; their importance, 87; effects of amosquito bite, 87; probable function of the saliva, 88; Howmosquitoes breathe, 89; Blood, 90; in body cavity, 90; heart, 90;Classification, 91; Anopheles, 91; distinguishing characters, 92;eggs, 92; where the larvæ are found, 93; Yellow fever mosquito,94; its importance, 94; the adult, 95; habits, 95; habits of thelarvæ, 95; Other species, 96; some in fresh water, others inbrackish water, 96; Natural enemies of mosquitoes, 97; hownatural enemies of mosquitoes control their numbers, 98; mosquitoesin Hawaii, 98; Enemies of the adults, 99; Enemies ofthe larvæ and pupæ, 100; Fighting mosquitoes, 101; fightingthe adult, 102; Fighting the larvæ, 103; domestic or localspecies, 104; draining and treating with oil, 104; combattingsalt-marsh species by draining, 105; by minnows or oil, 105. | |
| [CHAPTER VII] | |
| Mosquitoes and Malaria | 106 |
Early reference to malaria, 106; its general distribution, 106;theories in regard to its cause, 107; insects early suspected, 107;The parasite that causes malaria, 108; studies of the parasite,108; Life-history in human host, 109; its effect on the host, 110;the search for the sexual generation, 111; The parasite in themosquito, 112; review of whole life-history, 115; malaria transmittedonly by mosquitoes, 115; Summary, 117; experimentalproof, 118. | |
| [CHAPTER VIII] | |
| Mosquitoes and Yellow Fever | 120 |
A disease of tropical or semi-tropical countries, 120; outbreaksin the United States, 120; parasite that causes the diseasenot known, 121; formerly regarded as a contagious disease,122; The yellow fever commission, 123; Dr. Finlay'sclaim, 124; experiments made by the commission, 125; summaryof results, 129; what it means, 130; results in Havana,131; the fight in New Orleans, 132; In the Panama canal zone,135; in Rio de Janeiro, 136; claims of the French commission,138; habits of stegomyia, 139; breeding habits, 139; possibleresults of war against the mosquitoes, 139; Danger of this diseasein the Pacific Islands, 140. | |
| [CHAPTER IX] | |
| Fleas and Plague | 142 |
Great scourges, 142; the "black death," 142; old conditionsand new, 143; How plague was controlled in San Francisco,143; Indian Plague commission, 144; Dr. Simond's claim,145; The advisory committee and the new commission, 146;Results of Dr. Verjbitski's experiments, 147; Results of variousinvestigations, 150; structure and habits of fleas, 151; feedinghabits, 152; Common species of fleas, 153; Ground squirrels andplague, 155; squirrel fleas, 156; Remedies for fleas, 157; catsand dogs, 159. | |
| [CHAPTER X] | |
| Other Diseases, Mostly Tropical, Known or Thought toBe Transmitted by Insects | 161 |
Sleeping Sickness, 161; its occurrence in Africa, 161; causedby a Protozoan parasite, 162; the tsetse-fly, 163; Elephantiasis,164; caused by parasitic worms, 164; their development,165; how they are transferred to man, 165; effect on the patient,166; Dengue, 168; other names, 168; probably transmittedby mosquitoes, 170; Mediterranean fever, 171; cause,171; may be conveyed by mosquitoes, 171; Leprosy, 171;caused by a bacteria parasite, 171; possibilities of flies, mosquitoesand other insects transmitting the disease, 172; Kala-azar,173; transmitted by the bedbug, 173; Oriental sore, 174;the parasite may be carried by insects, 174. | |
| [Bibliography] | 175 |
Parasites and parasitism, 175; Protozoa, 176; Bacteria, 177;Insects and disease, 178; Mosquitoes—systematic and general,179; Mosquito anatomy, 182; Mosquitoes—life-history andhabits, 183; Mosquito fighting, 183; Mosquitoes and disease,185; Malaria, 186; Yellow fever, 189; Dengue, 192; Filarialdiseases and elephantiasis, 193; Leprosy, 193; Plague, 194;Fleas, 198; Typhoid fever, 199; House-flies—anatomy, life-history,habits, 200; House-flies and typhoid, 202; House-flyand various diseases, 203; Human myiasis, 207; Stomoxysand other flies, 208; tsetse-flies, 209; Trypanosomes and Trypanosomiasis,210; Sleeping sickness, 211; Rocky mountainfever and ticks, 212; Ticks and various diseases, 213; Kala-azarand bedbugs, 216; Text or reference books, 216; Miscellaneousarticles, 218. | |