LIST OF ILLUSTRATIONS. FIG. 1. Caudal bursa of a male strongyle (Esophagostoma dentatum) to serve as diagram for the family.......... 2-9. New World hookworm (Uncinaria americana). 2. New World male hookworm. 3. New World female hookworm.. 4. The same enlarged to show the position of the anus and vulva....... 5. Dorsal view of anterior end of New World hookworm. 6. Lateral view of anterior end of New World hookworm 7. Lateral view of caudal bursa of New World male hookworm.. 8. Caudal end of New World male hookworm.. 9. Four eggs of New World hookworm 10-41. Old World hookworm (Agchylostoma duodenale). 10. Dorsal view of anterior end of Old World hookworm... 11. Old World male hookworm... 12. Old World female hookworm... 13. The same (diagrammatic) enlarged to show the position of the anus and vulva... 14. Semidiagrammatic figure of caudal bursa of same... 15. Lateral view of Old World male hookworm enlarged to show the anatomy 16. Eggs of Old World hookworm... 17-29. Embryology of Old World hookworm.. 30-31. Larvæ at the end of the second stage (encysted larvæ) ... 32. A young hookworm of man, without buccal capsule, four days after infection.. 33. Anterior end of larval hookworm during formation of provisional buccal capsule..... 26 34. Head of larval hookworm before entering the fourth stage, five days after infection ...... 35. Young hookworm in fourth stage, with provisional buccal capsule... 36. Provisional buccal capsule (fourth stage) of larval hookworm, about nine days after infection.... 37. Young male hookworm, about nine days after infection.... 38-39. Development of definite buccal capsule..................... 40-41. Male and female hookworms before the fourth casting of skin, fourteen to fifteen days after infection ............. 42. A severe case of hookworm disease observed in Florida... 43-85. Eggs and embryos of other parasitic worms. 43. Egg of common eelworm or ascaris (Ascaris lumbricoides) of man........... 44. The same, optical section, seen with median focus.... 45-54. Embryology of common ascaris of man after the egg is discharged in the feces.... 55. Embryo of the common ascaris of man, in its eggshell FIG. 56. Free embryo of common ascaris of man, casting its skin... Page 82 65. Embryo of the common pinworm of man, in the eggshell, as found in the fresh feces...... 82 66. Full-grown embryo of the common pinworm of man, escaped from its shell...... 67-70. Egg of common whipworm (Trichuris trichiura) of man, showing changes undergone while still in the female worm; fig. 69 is the stage found in fresh feces.... 71-73. Later stages of development of an allied whipworm (Trichuris affinis) of sheep and cattle, showing changes after the egg escapes in the feces 74. Isolated embryo of Trichuris affinis. 75. Egg of Cochin-China diarrhea worm (Strongyloides stercoralis). 76. Rhabditiform embryo of same. 77. Filariform larva of same.. 78. Egg of common liver fluke (Fasciola hepatica) examined shortly after it was taken from the liver of a sheep. This is the same stage found in human feces.... 79. Egg of common liver fluke containing a ciliated embryo (miracidium) ready to hatch...... 80. Embryo of the common liver fluke boring into a snail. 84 84 84 81. Egg of lancet fluke (Dicrocœlium lanceatum) with contained embryo.. 82. Egg of human-blood fluke (Schistosoma hæmatobium) with contained embryo, passed in the urine or in the feces. 84 84 83. Egg of beef-measle tapeworm (Tania saginata), with thick eggshell 84. Eggs of pork-measle tapeworm (Tania solium): a, with primitive 84 84 85 94 SUMMARY Convinced from theoretical deductions that hookworm disease (uncinariasis) must be more or less common in the South, a trip was made from Washington, D. C., to Ocala, Fla., stopping at penitentiaries, mines, farms, asylums, schools, and factories, and the fact was established that the chief anemia of the Southern rural sand districts is due to uncinariasis, while clay districts and cities are not favorable to the development of this disease. In the Old World, hookworm disease was probably known to the Egyptians nearly three thousand five hundred years ago, but its cause was not understood until about the middle of the nineteenth century, when it was shown to be due to an intestinal parasite, Agchylostoma duodenale. Until 1893 no authentic cases of this disease were recognized as such in the United States, but between 1893 and 1902 about 35 cases were diagnosed. In 1902 it was shown that a distinct hookworm, Uncinaria americana, infests man in this country, and this indicated very strongly that the disease must be present although not generally recognized. It is now established that in addition to the few cases of Old World hookworm disease imported into the United States we have in the South an endemic uncinariasis due to a distinct cause, Uncinaria americana. This disease has been known for years in the South and can be traced in medical writings as far back as 1808, but its nature was not understood. Some cases have been confused with malaria, others have been attributed to dirt-eating. The hookworms are about half an inch long. They live in the small intestine, where they suck blood, produce minute hemorrhages, and in all probability also produce a substance which acts as a poison. They lay eggs which can not develop to maturity in the intestine. These ova escape with the feces and hatch in about twenty-four hours; the young worm sheds its skin twice and then is ready to infect man. Infection takes place through the mouth, either by the hands soiled with larvæ or by infected food. Infection through the drinking water may possibly occur. Finally, the larvæ may enter the body through the skin and eventually reach the small intestine. Patients may be divided into light cases, in which the symptoms are very obscure; medium cases, in which the anemia is more or less marked, and severe cases, represented by the dwarfed, edematous, anemic dirt-eater. Infection occurs chiefly in rural sand districts. Above the frost line the symptoms are more severe in summer than in winter, and whites appear to be more severely affected than negroes. Persons who come in contact with damp earth are more commonly infected than others, so that the disease is found chiefly among farmers, miners, and brickmakers. Severe cases are more common in women and children than in men over 25 years of age. Uncinariasis is a disease which occurs in groups of cases, and if one case is found in a family the chances are that other members of the same family are infected. The testimony of patients severely infected is unreliable. Recalling that any one or more symptoms may be absent or subject to variation, it may be noted that the period of incubation (at least before the malady can be diagnosed by finding the eggs) is from four to ten weeks. Stages are not necessarily distinctly defined, but are described as (1) stage of purely local symptoms, corresponding to the light cases; (2) stage of simple anemia, corresponding to the medium cases; and (3) dropsical stage, corresponding more or less to the severe cases. The duration of the disease after isolation from the source of infection has been traced for six years and seven months; how much longer infection will last is not established. If a patient is subject to cumulative infection, the disease may last five, ten, or even fifteen years, and in case of light infection perhaps longer. External appearance.-In extreme cases there is a general lack of development: skin waxy white to yellow or tan; hair is found on the head, but is more or less absent from the body; breasts are undeveloped; nails white; external genitalia more or less rudimentary; face anxious, may be bloated; conjunctivæ pale; eyes more or less dry, pupil dilates readily; membranes pale according to the anemia; teeth often irregular; tongue frequently marked with purple or brown spots; cervical pulsations prominent; thorax emaciated; heart beats often visible; abdomen frequently with "pot belly;" extremities emaciated, frequently edematous, and with wounds or ulcers of long standing. Urine 1010 to 1015; in advanced cases albumin without casts; acid or alkaline. Feces reddish brown, contain eggs, and may contain blood. Circulatory system.--Anemia pronounced, according to degree and duration of infec tion; blood watery, with decreased red blood corpuscles and with eosinophilia: "heart disease" very commonly complained of; hemic murmurs present; pulse 80 to 132 per minute. Temperature.-Subnormal, normal, or to 101° or 102° F. Respiratory system.-Breathing may be difficult, slow, or increased to as high as 30. Muscular system.-Emaciation and great physical weakness. Digestive system.-Appetite poor to ravenous; abnormal appetite often developed for pickles, lemons, salt, coffee, sand, clay, etc.; pain in epigastrium; constipation or diarrhea. Nervous system.-Headache, dizziness, nervousness, mental lassitude, and stupidity. Genital system.-Menstruation irregular or absent; if present, it occurs chiefly in winter; there is a marked tendency to abortion. Diagnosis.-The safest plan is to make a microscopic examination of the feces to find the eggs; or, if feces are placed on white blotting paper, a blood-like stain will be noticed. Treatment.-Thymol, or male fern (or? calomel); iron, and good food. Prevention.-Treat all cases found and dispose of feces. Economically, uncinariasis is very important. It keeps children from school, decreases capacity for both physical and mental labor, and is one of the most important factors in determining the present condition of the poorer whites of the sand and pine districts of the South. The disease is carried from the farms to the cotton mills by the mill hands, but does not spread much in the mills; nevertheless, it causes a considerable amount of anemia among the operatives. REPORT UPON THE PREVALENCE AND GEOGRAPHIC DISTRIBUTION OF HOOKWORM DISEASE (UNCINARIASIS OR ANCHYLOSTOMIASIS) IN THE UNITED STATES. By CH. WARDELL STILES, Ph. D., Chief of Division of Zoology, Hygienic Laboratory, U. S. Public Health and MarineHospital Service. INTRODUCTION. Thoroughly convinced from theoretical zoologic considerations, especially of a faunistic nature, that uncinariasis must be a more or less common disease in the Southern portion of the United States, I requested instructions from Surgeon-General Wyman to study the subject in a field investigation. The desired authorization was received and the results of the work are contained in this paper. DEFINITION. Uncinariasis is a specific zooparasitic disease found especially in tropical and subtropical sand areas, and caused by hookworms (genus Uncinaria) which inhabit the small intestine. Its chief symptoms are: Anemia, with the circulatory symptoms found in all extreme anemias, namely, dizziness, palpitation, hemic murmurs; great weakness, in some cases with considerable emaciation; colicky pains in the abdomen; perverted appetite, such as "dirt-eating;" constipation or diarrhea, stools sometimes brownish or bloody; nausea; edema. The only positive diagnosis is by finding the parasite or its eggs in the stools. It may affect any class of patients, but is more frequent in persons whose daily life brings them in contact with damp earth (children, farmers, miners, brickmakers, excavators, etc.). TERMINOLOGY. The disease now under discussion is known by a number of different names, but uncinariasis" should be adopted as the more correct technical designation. Among the names frequently applied to it, the a Looss (1902) has recently attempted to suppress the term "uncinariasis" in favor of anchylostomiasis, his view being that the genus Agchylostoma is distinct from Uncinaria. His suggestion does not help matters much at present. Even if the zoological genera are recognized as distinct, uncinariasis would still exist in man, while among animals it would be still more common than anchylostomiasis. Further, the two genera would probably have to be united in a subfamily, which could then be called "Uncinariinæ," and uncinariasis could then signify any infection of any |