In the process of human evolution, man has inevitably suffered from various diseases as a part of his biological destiny. These diseases have influenced not only the lives and subsistence of individuals, but have also had an influence upon society, culture, and even the history of mankind. All human beings, from ancient times onward, seem to have recognized pathological conditions which could be a menace to their lives and could lead to the collapse of their society.

Today, although great advances have been made in medical science and the etiology and therapy for many diseases have been thoroughly elucidated, some interesting problems remain to be solved concerning the history of man and disease: What was the attitude of people with regard to virulent disease, and how did they become infected by disease in ancient times? How did they finally die of such diseases without the aid of advanced medical technology? Such problems regarding the historical relationship between man and disease have recently become the center of wide interest.

One method of approaching these problems has been through "medical history," which relies mainly on the descriptions of medical matters and the pictures of pathological conditions of ancient people presented in earlier literature. From such early medical descriptions and records, the diseases affecting ancient populations are being diagnosed by medical historians in light of modern medical science. In Japan, systematic studies based on numerous earlier literature were carried out by FUJIKAWA (1902, 1904, 1912), who discovered many previously unknown early palaeographs recording epidemics of measles, dysentery, smallpox, cholera, typhoid fever, and syphilis. The origin of syphilis in this country and the history of syphilology in the world were discussed from the viewpoint of medical history by DOHI (1902, 1921) in his excellent work entitled "The World History of Syphilis."

Recent studies based on the work done by FUJIKAWA and DOHI support their conclusion that syphilis must have been transmitted into Japan from the east coast of China (the Canton district) in about 1512 A.D., namely during the Muromachi period (1338-1573 A.D.).

In recent years, especially since the end of World War II, another approach to elucidating the health status of ancient populations and the prevalence of certain diseaseshas developed based upon the rapidly increasing excavation of human skeletal remains which often display various pathological conditions. The terms "palaeopathology" and "palaeoepidemiology" have generally been applied to such studies. Both fields of study are closely related to archaeology, anthropology, pathology, epidemiology, and other fields of medicine and have evolved through the increasing collection of materials and the development of research techniques for diagnosis and interpretation of bone pathology.

General books broadly covering these fields have been published by WELLS (1965), HENSCHEN (1966), JARCHO (1966), and BROTHWELL (1972). In his studies on the evidence of syphilis in ancient times, HENSCHEN, for one, described the possible evidence of syphilis in the crania of pre-Columbian Indians from Peru and Mexico which revealed widespread areas of ostitic erosion on the vaults. BROTHWELL has also described a medieval specimen from London which showed extensive destruction of bone occurring in the region of the face and upper part of the skull due to syphilis. In 1967, the large volume "Diseases in Antiquity," edited by BROTHWELL and SANDISON, which contains many interesting and useful papers, was published. GOFF, one of the contributors, described the typical pathological changes in osseous syphilis andreported some new pre-Columbian materials from Guatemala and Mexico which probably revealed evidence of venereal syphilis. STEINBOCK (1976) provided excellent detailed descriptions and interesting illustrations of gross pathological changes in syphilitic lesions in the cranium. And in this study the present author has attached considerable importance to those precious studies on osseous syphilis.

In Japan, the first palaeopathological study was done by ADACHI (1895), who studied a Jomon skeleton excavated from the Furusaku shell mound in Chiba Prefecture, and investigated diffuse hypertrophic lesions found in tibia and fibula. He concluded that syphilis might have existed during the Stone Age in this country. DOHI (1921), who reexamined the same materials in detail, however, disagreed with ADACHI'S conclusion and stated that syphilis did not originate in this country during the Stone Age but must have been transmitted into the western part of Japan from the east coast of the Canton district of China in about 1511 or 1512 A.D.

KIYONO and HOSHIJIMA (1922) made detailed investigations of 160 skeletal remains excavated from various sites throughout Japan (138 from shell mounds of the Stone Age, and 22 from tombs of the Kofun period). They described many pathological changes such as skeletal trauma, benign osteoma, auricular exostosis, and degenerative changes in the vertebral columns. KIYONO (1949), KIYONO et al. (1927, 1928), and colleagues such as MIYAKE and IMAMICHI (1931), IMAMICHI (1934), and OKURA (1939) made repeated studies in this field, although they rarely dealt with the problems of osseous syphilis in ancient populations in Japan, SUZUKI (H; 1956) studied a large number of medieval Japanese skeletons excavated from Zaimokuza in Kamakura and reported in detail on injured bones from a large-scale battle which took place in 1333 A.D. (Yoshisada NITTA'S attack on Kamakura). KUMAGAI (1958) reported on various pathological changes found in skeletal remains of the Yayoi period (ca. 300 B.C. to 300 A.D.) excavated from Doigahama, Yamaguchi Prefecture. SAKURA (1964) studied historical changes in the frequency of dental caries among ancient people in this country.

Special attention should be paid to the descriptions of syphilis in the skulls of the Muromachi period reported by SUZUKI (H; 1963). According to SUZUKI, three out of twenty-three skulls of that period excavated from Kaji-bashi in Tokyo showed the characteristic features of osseous syphilis (see Plate 3).

Published materials on human skeletal pathology have gradually increased, and, although few, epidemiological analyses of ancient populations of Japan have also been published. Works by the following authors contained valuable case reports of interesting pathological bone changes and/or studies broadly covering the general palaeopatho logical field, with the exception of osseous syphilis: OGATA (1972, 1981), SUZUKI (H; 1958, 1975), NAITO (1974), MORIMOTO and OGATA (1976), SUZUKI (T; 1978, 1981), SUZUKI and IKEDA (1981), and TASHIRO (1982).

In the present study, the author considers the effects on human skeletal remains of syphilis, which usually produces characteristic features on dried bone and which appears to have been extremely prevalent in the Japanese population in earlier centuries, particularly during the Edo period (1603-1867).

This paper is a doctoral dissertation submitted to the Faculty of Science, The University of Tokyo, in 1982.

Syphilis As is generally known, syphilis is one of the most virulent of venereal infections because of its frequency, seriousness, and various manifestations; this being true in particular among primitive societies.

Syphilis is usually divided into three stages based on clinical manifestations and duration after infection. The primary stage of syphilis is characterized by hard chancres with small erosions or deep ulcers on the genital organs. In the secondary stage of syphilis, the principal lesions involve the skin and mucous membrane. The tertiary stage of syphilis appears three or more years after the initial infection. Nearly all organ systems, such as the cardiovascular system, the central nervous system, the respiratory tract, and the skin and skeletal systems, are involved in this stage characterized by gumma. The skeletal system, in particular, is one of the most common sites of lesion during this stage. The bones most frequently involved are the skull, tibia, femur, and vomer. Gumma of the bone sometimes cause spontaneous fractures and such deformi ties as "saddle nose." These destructive changes in the skeleton, which mainly result from gumma of the bones, may be considered, from the palaeopathological point of view, as characteristic signs of osseous syphilis.

Spirochetes of the genus Treponema are also responsible for certain diseases that in many respects resemble syphilis but do not carry the stigma of a venereal infection (HAAM, 1977). These nonvenereal diseases are yaws (framboesia), pinta, and bejel. The geographical and historical evidence for these human treponematoses has been discussed in detail by HACKETT (1967).

It is said that bone changes during the tertiary stage of yaws are indistinguishable from those of syphilis. There have been many discussions on the differential diagnosis between the osseous syphilis and osseous yaws of skeletons excavated from the areas in which these two diseases once coexisted (PUTSCHAR, 1966; STEINBOCK, 1976). In Japan, however, there has been no evidence of the existence of the above-mentioned tropical endemic non-venereal infections either in the past or at present. Thus in the present context, it is unnecessary to consider these non-venereal diseases seriously in a differential diagnosis of syphilis among unearthed skeletal remains from Japan.

The early prevalence of syphilis in palaeographs It was in the decade following 1510, the late Muromachi period, when the power and authority of the Muromachi government had almost completely disappeared, that the first outbreak of a virulent venereal infection appeared among the people and suddenly disseminated itself in epidemic proportions in this country.

The oldest documents describing the appearance of syphilis in Japan are the "Gekkai-roku" and the "Myohoji-ki" (FUJIKAWA, 1904, 1912). The "Gekkai-roku" is a kind of medical essay written by Shukei TAKEDA, a famous doctor in Kyoto during the Muro-machi period. He reported the first outbreak of syphilis in the Kansai district in 1512 (Eisho 9 on the Japanese calender) and described curious eruptions on the skin which were called Tau-mo (Chinese eruption) or Ryukyu-mo (ryukan eruption) by the general population. The "Myohoji-ki" (Myohoji temple's records) is a kind of miscellany written by many Buddhist priests who lived in Myohoji temple, located in Kawaguchiko, Yama-nashi Prefecture, during the Muromachi and Edo periods. In this miscellany, various occurrences in the Kanto district were recorded, and it shows that there was a large outbreak of syphilis in 1513 A.D. around this district, i.e., a strange epidemic with large and curable eruptions called Tau-mo was reported in its pages as having spread widely among the people.

This virulent epidemic of syphilis struck the unsuspecting Japanese without distinction as to age or sex. During the Edo period, the people were familiar with syphilis and called it by various names such as Tau-mo, Tau-kasa, kasa, yo-bai-so sau-doku, bai-sau, and bai-doku. There are many documents and much literature dealing with the clinical manifestations of and therapies for syphilis during the middle and late parts of this period.

From an account written by Keisuke FUNAKOSHI during the 1830s, for example, the clinical processes of syphilis during the Edo period seem to have been characterized by such manifestations as initial sclerosis, hard buboes, syphilitic eruptions, alopecia, severe pain and swelling of the bones, suppurative and erosive ulceration, and decom position or rotting of tissue (e.g. FUNAKOSHI, 1838). Many other authors such as Nankei TACHIBANA, Genpaku SUGITA, and Ryqjun MATSUMOTO also reported how numerous people were suffering from virulent venereal syphilis. The last of these authors, MATSUMOTO, who was the first physician with a truly scientific idea of hygiene and epidemiology and who conducted a systematic VD examination for prostitutes in Nagasaki in 1860 (Man'en 1 on the Japanese calendar), described the prevalence of syphilis and its causa tive environment as follows: "Syphilis may infect about 95 percent of the people among the humbler classes. The terrible prevalence of syphilis could be caused by the lenient and loose control of the prostitution without strict regulations."

During the Meiji period (1868-1915), particularly from the later half of this period, the real necessity for preventing and reducing the incidence of venereal infections among the people was at last widely recognized scientifically from the points of view of public hygiene and national prestige, and clinical and epidemiological data on venereal diseases, including syphilis, were gradually published.