Why Did Doctors Fail to Classify Diseases Like Plants?

On the evening of the last day of the year, a very short year-end concert was held at the hospital where I work. We played 《Auld Lang Syne》 on the bamboo flute in the lobby. The patients responded with humming. We finished the short concert, which lasted less than 10 minutes, with an encore of another bamboo flute piece.

When I returned to the consultation room, I could hear the patients singing. The patients in their 60s and 70s sang a few popular songs in the hospital lobby, adding a bit of dance. I could also hear the song 《Camellia Lady》 by Im Yeong-ja.

A Small Year-End Concert and the Song Echoing in the Hospital Lobby

For the elderly generation of South Korea, 《Camellia Lady》 is not just an ordinary popular song. After its release, 《Camellia Lady》 became a massive hit and was later banned for a long time before being revived. Sitting in the consultation room, listening to the patients sing 《Camellia Lady》, I thought, "The patients who had tea with me chose the right song."

The tea tree belongs to the genus Camellia. It is a song that has a common denominator among the patients who talked with me over tea. And my thoughts raced through the camellia flower to the classification of diseases.

The camellia tree is a species of tree included in the genus Camellia. The camellia tree grows slowly and lives a long time. It can survive for decades or even centuries. It has evergreen leaves that do not fall in all four seasons. Always green but not showy, the camellia tree grows slowly but lives long; it is a plant that endures rather than displays.

The camellia flower drops whole without scattering its petals. It maximizes pollination efficiency by tightly binding many stamens to the petals, and after blooming, it separates from the branch without hesitation to avoid infection and energy waste.

The petals that fall whole decompose slowly on the ground, creating a favorable soil environment for its species. Through this dropping, the camellia flower shows a "waste-free exit" along with a "quiet contribution for the next generation."

The Symbolism of the Dropping Camellia Flower and 《La Traviata》

This camellia flower, with such symbolism, enters the center of European culture in the mid-19th century through Alexandre Dumas' 《Camellia Lady》 and Verdi's opera 《La Traviata》.

In 1848, Dumas published the story of a woman in Parisian high society and the man who loved her. The story between the two always features the camellia flower. Dumas introduced the camellia flower, which did not grow in Europe, instead of roses, lilies, or violets in his love story.

The protagonist, Violetta, always carried a camellia flower. The camellia flower was not used as decoration but as a language. It expressed the days she could meet a man and the days she could not.

The novel soon expanded into music. Verdi composed the opera 《La Traviata》 based on Dumas' original work, which premiered in 1853 at the La Fenice Theatre in Venice. The heroine, Violetta, always appears with the camellia flower in the opera.

Violetta, who suffers from tuberculosis, meets Alfredo and receives a confession of love, and they fall in love. However, faced with Alfredo's father's opposition, Violetta sacrifices her love to protect Alfredo and leaves him.

The chosen sacrifice is the core of this tragedy. Violetta's illness worsens, and although Alfredo returns, she quietly ends her life.

The protagonist's unembellished death and completed exit resemble the end of the camellia flower. It shows the dignity of extinction. Through the novel and opera, the camellia flower has come to symbolize conditional love, forbidden relationships, frailty and nobility, and something beautiful but not long-lasting.

18th Century Europe: From Linnaeus' Plant Classification to Human Disease Classification

The reason the scientific name of the camellia flower (Camellia japonica) has the term 'japonica' meaning Japan is related to the situation of the plant classification era. Plant classification was centered in 18th century Europe. In 1753, Carl Linnaeus established a classification system in 《Species Plantarum》 that continues to this day.

Linnaeus believed that nature could be organized and systematized through orderly and correct observation and naming. At this time, the binomial nomenclature (genus + species name) was established, and classification was based on specimens brought to Europe. The local classification system was merely a reference. All plants in the world were classified and named according to these principles.

The reason the ornamental camellia flower was given the name japonica is that Europeans recognized its Japanese origin. Although the camellia flower also inhabited the southern part of the Korean Peninsula at that time, European botanists perceived and named it as a plant that grew in Japan.

Even before the botanical name was established, Dutch scholars stayed on Dejima Island in Japan, and the Japanese provided them with camellia flower specimens. The Dutch scholars introduced the camellia flower to mainland Europe, and the camellia tree became known as a Japanese plant, acquiring the name japonica.

The same goes for the tea tree, which belongs to the same genus as the camellia tree. Before plant classification, all knowledge about tea was already well organized by the Chinese. When the tea tree was introduced to European botany, it was already present in Korea and Japan, but the tea tree, which had been highly experienced by the Chinese, was seen by European scholars as the Chinese tea tree.

However, European classifiers could not simply use the Chinese name for the tea tree as the name used by the Chinese deviated from the principles of Latin binomial nomenclature. European botanists named it 'Camellia sinensis' (Camellia sinensis), meaning Chinese camellia. 'Sinensis' means 'from China.'

Classification is a means of reflecting how actual things exist. When classification is done according to the order of nature, it is more practical and reflects the truth.

However, classification can also be done based on utility and convenience. Library classification is a representative example. It was somewhat amusing when my book about tea was classified under the major category 《Home》, the middle category 《Cooking》, and the minor category 《Beverages》.

Still, 18th-century plant classification relatively reflected the order of nature and the truth. Linnaeus excluded human uses, medicinal effects, and symbols. He established a classification system based on the forms that plants reveal themselves, especially the structures of flowers, leaves, fruits, stamens, and pistils, such as the number of petals, the number and arrangement of stamens, and the structure of the pistil, which are repetitive and stable forms.

It can be seen as a classification system that distorts nature the least. In this century, it has been challenged by concepts such as evolution and variation, but the 18th-century plant classification system was a groundbreaking knowledge system for its time.

Plant classification also seduced contemporary physicians. Plant taxonomy changed the way doctors thought about diseases. For physicians before Linnaeus, diseases were not fixed entities but events that appeared differently each time. They were individual conditions. Therefore, until then, medicine focused on listing and describing symptoms.

However, after Linnaeus, physicians began to think of diseases as the same forms that appear repeatedly. Diseases became objective entities.

Physicians began to think of diseases as distinguishable natural species and sought to classify them and give them unique names. Diseases began to writhe, reborn through the eyes of doctors rather than the bodies of patients.

Labels Attached to Diseases…The Dream and Limitations

Notable figures pursuing disease classification at that time included François Boissier de Sauvages from France and William Cullen from Scotland. The botanist Linnaeus, who was also a physician, participated in this.

They primarily embarked on disease classification based on symptoms. Since the 17th-century British physician Thomas Sydenham, diseases had been described mainly based on symptoms, and there was a strong belief that the symptoms of diseases were the same.

However, diseases were not classified systematically like plants. Unlike fixed plants, diseases are 'events' and 'processes.' They vary over time, differ from patient to patient, and depend on conditions.

Moreover, while plants are independent entities, diseases are the result of interactions between the body and the environment. Diseases overlap and mix, and their identities change over time. It was impossible to classify such diseases and define them as fixed species like plants.

In the case of Sauvages, he placed 'weakness' (衰弱) under the 《Genus》 with 'sensory impairment, voluntary motor impairment, appetite loss, vitality loss, and all functional decline' under 《Order》. Then, under 'voluntary motor impairment,' he placed 'paralysis of the lower limbs, hemiplegia, aphasia, mutism, and stuttering' under 《Family》. And under 'hemiplegia,' he placed 'apoplectic, traumatic, epileptic, and lead mine hemiplegia' as 《Species》. Through this classification, diseases were given names. However, this naming did not deepen the understanding of diseases.

Currently, terms like genus, order, family, and species are not used in disease classification. However, the tradition of placing smaller categories under larger categories remains.

In modern times, there is a tendency to classify diseases mainly based on their causes. However, a perfect logical classification system is still lacking. For example, it has not been resolved whether to classify kidney infections as kidney diseases or infectious diseases.

The dream of natural classification that started from plant taxonomy has been institutionalized as the International Classification of Diseases (ICD), albeit imperfectly. The coded ICD is used effectively for disease definitions, statistics, administration, insurance, and epidemiology.

Yoo Young-hyun, Director of Tea Clinic (Audio Column 1+1 Story https://www.youtube.com/@yhyoo0906)