Masao Ota: A Pioneer of Modern Dermatology
A biographical study of Masao Ota / Mokutaro Kinoshita was initiated in 2009 as a serialized work in the journal Hifuka no Rinsho (Clinical Dermatology) by Professor Ken-ichi Ueno (Professor Emeritus, University of Tsukuba) under the title “Mokutaro: Gleanings.”
Following Professor Ueno’s passing, the series was continued by Professor Tomomichi Ono (President of Kumamoto Health Science University). Beginning with the May 2013 issue, it appeared under the title “Masao Ota / Mokutaro Kinoshita: Global and Humanitarian,” and continued until March 2017.
To write something further about Masao Ota may appear presumptuous in view of the distinguished work already produced by these two scholars. Nevertheless, I would like to present a brief summary. My reasons are twofold: first, to express respect to those predecessors who have introduced this giant of dermatology with such depth and dignity; and second, to encourage readers—particularly younger dermatologists who may not yet know Masao Ota—to read these biographies.
If this summary encourages readers to consult their works, it will be my great pleasure. If it fails to do so, the responsibility must lie solely with my own limited ability to summarize.
Because the achievements of Ota are enormous and the materials concerning him are abundant, I cannot hope to summarize them adequately. I will therefore briefly outline his life by dividing it into two aspects: Masao Ota as a dermatologist and Mokutaro Kinoshita as a man of letters.
First, I will describe Masao Ota as a dermatologist.
Brief Chronology
1885 (Meiji 18) — Born in Ito City, Shizuoka Prefecture, the youngest child in a family of seven (four sons and three daughters) in a household operating a drapery and general goods shop called Komesō.
Age 14 — Entered the German Association Middle School in Tokyo.
1903 (Meiji 36) — Entered the Third Division (medical course) of the First Higher School.
1906 (Meiji 39) — Entered the Faculty of Medicine, Tokyo Imperial University.
1912 (Meiji 45) — Joined the Department of Dermatology and Urology of Tokyo Imperial University. Before this he spent seven months conducting bacteriological research in the Department of Hygiene.
1916 (Taisho 5) — Appointed Professor at the South Manchurian Medical College.
1921 (Taisho 10) — Studied in France.
1924 (Taisho 13) — Appointed Professor of Dermatology at Aichi Prefectural Medical College (now Nagoya University School of Medicine).
1926 (Taisho 15) — Became Professor at Tohoku Imperial University.
1937 (Showa 12) — Appointed Professor at Tokyo Imperial University, concurrently serving as a member of the Institute for Infectious Diseases.
October 15, 1945 — Died.
Among the many recollections written about Mokutaro Kinoshita, the most vivid portrayal—including his medical achievements—appears in the memorial essays of Kanahiko Kitamura (1889–1989), who succeeded him directly and later served as Professor at the University of Tokyo from 1946 to 1959.
Professor Ueno wrote that Kitamura’s recollections bring Mokutaro’s figure “concretely and vividly into view, almost as if by magic.”
Based on these accounts, and especially on the biographies by Professors Ueno and Ono, the following outline of Ota’s achievements may be presented.
Mycology
After joining the dermatology department of Tokyo Imperial University, Ota devoted himself to the microscopic observation and drawing of fungi. He studied Sabouraud’s textbook of mycology and also became familiar with the French language. During his stay in France he studied under the great scholar Raymond Sabouraud.
At that time Sabouraud was already a great authority, and it seems that he somewhat underestimated the unknown young physician from the Far East. When Ota sent him his discovery of dyshidrotic-type tinea, Sabouraud replied with a rather severe letter that did not recognize its importance.
Ota later complained that Sabouraud and others did not believe him at all and that he even stopped some experiments.
Nevertheless Ota later proposed a new botanical classification of fungi (the Ota–Langeron classification), and for this he received the French decoration Légion d’honneur.
He later recalled that Sabouraud had expressed some dissatisfaction with this classification.
However, at Sabouraud’s death Ota wrote a tribute praising his achievements and describing him as a man of great culture who was also accomplished in classical studies, music, and sculpture.
In recent years Hideyo Yamaguchi has pointed out that modern classifications of fungi based on molecular biology correspond surprisingly well with the classification proposed by Ota nearly a century ago. This demonstrates the remarkable accuracy of Ota’s morphological observations.
Yamaguchi also described his excitement when a fungal strain originally isolated by Ota (Microsporum ferrugineum) was rediscovered in Europe and cultured again, producing the characteristic rust-colored colony exactly as described in Ota’s original paper.
Ota published 39 papers on fungi (16 in Japanese, 5 in German, 16 in French, and 2 in English).
Nevus Research
Nevus of Ota is perhaps the achievement that established Masao Ota as a world-renowned dermatologist.
Soon after arriving at the University of Tokyo he focused on this condition. In 1939 he published the landmark paper:
“On a Type of Nevus Frequent in Japan — Nevus fuscoceruleus ophthalmo-maxillaris — and its Relationship to Ocular Pigmentation.”
In this paper he wrote:
“The type of nevus described here has hitherto generally been diagnosed as a pigmented nevus and has therefore not attracted particular attention among specialists. However, it differs in nature from pigmented nevi and should rather be regarded as a special form of blue nevus.”
His observations already contained the essential features of what is now known as nevus of Ota.
Research on Hansen’s Disease
Ota also conducted important studies on Hansen’s disease.
He collaborated with members of the Japanese Leprosy Society on the classification of the disease and its histopathological basis.
He concluded that leprosy was not an incurable disease and that if an effective therapeutic agent were discovered, complete cure should be possible.
Evaluation of His Achievements
Some critics have argued that because Ota extended his talents into many fields, he only “sang the overture but did not complete the opera.”
The writer Koji Uno wrote:
“He was a connoisseur to the marrow of his bones and possessed talent in almost every artistic field, yet he could not pursue any one of them through to the end.”
The moulage artist Kentaro Hasegawa also criticized him:
“If he had devoted himself either to medicine or to literature, he might even have received the Order of Culture. But he had too many interests.”
In response, Professor Ueno interpreted the so-called “overture problem” differently.
He suggested that Mokutaro’s intellectual “sensor” was so sharp that he quickly grasped the essence of problems and moved on to new themes.
If an overture is understood in its original meaning as an overview of the entire opera (Übersicht), then to say that “Mokutaro sang the overture” means that he grasped the essence of a problem as a whole.
It is impossible to cover fully the biographies written by Professors Ueno and Ono.
Next time I would like to describe several episodes in the life of Masao Ota as a dermatologist.
English version prepared with AI assistance
(Originally published in Japanese)