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The herbarium sheet
Perspectives
Object lessons The herbarium sheet Despite the power of synthetic chemistry, medicine still needs the natural products of plants. Plants are important as potential sources of new drugs. In the past they provided the raw materials for therapeutics. Using the correct kind of plant was important, since plants can poison as well as heal. But the species was also important. One common way of recording their identity and establishing permanent preserved specimens was with the herbarium sheet. This simple piece of paper held the dried and pressed plants parts, which could then be labelled with the name and place of origin. From the 16th century collections of herbarium sheets have been important components of botany. In some cases, herbaria provide the “type” specimen, the original example from which a new species is differentiated. As our world becomes more biologically impoverished, they are also a historical record of lost biodiversity. Herbaria offer a permanent legacy of the natural world that can be consulted long after the specimen was procured and preserved.
© The Board of Trustees of the Royal Botanic Gardens, Kew. Reproduced with the consent of the Royal Botanic Gardens, Kew
For more on Object lessons see Comment Lancet 2015; 386: 939 and Perspectives Lancet 2015; 386: 945, 1525, 1933, and Lancet 2016; 387: 113
*Bill Bynum, Helen Bynum Herbarium sheet for Cinchona officinalis
1046
These things matter for medicine. The herbarium sheet for Cinchona officinalis shown here comes from the Herbarium at the Royal Botanic Gardens Kew, in London, UK. The genus Cinchona contains some 23 species, but the biologically active bark is highly variable in the different species. Three species are especially rich in more than 20 active substances. This was known even before the alkaloids, of which quinine and quinidine are the most important, were isolated in the early 19th century. It was consequently essential that the right species was used, both in extracting the “bark”, as the medicine was long known, and in obtaining seeds for transplanting elsewhere. Its other appellations, Peruvian bark and Jesuit’s bark, hint at its early history. The inhabitants of western South America, where the trees are indigenous in the tropical Andean forests, used the bark as a febrifuge, whence the Spanish learned of it. The story goes that the Viceroy of Peru’s wife, the Countess of ChinchÓn, was cured of a fever in 1638. It probably wasn’t malaria, but the story took hold, and the bark was brought to the Old World in the early 17th century. Malaria was then common in much of Europe and demand for the new drug was high. Thomas Sydenham (1624–89) was so impressed with its power to root out the ague (mostly quartan malaria caused by Plasmodium malariae) that it stimulated him to argue that diseases could be classified just like plants and animals. A century later, Linnaeus named the tree’s genus and some of its species. He misspelled the Countess’s name, but, as is the custom of biological nomenclature, Cinchona became the perpetual name. The vagaries of botanical nomenclature (more than 330 names have been given to Cinchona) are seen at the bottom of this picture—all the names here are synonyms for C officinalis. This herbarium sheet was first dated in 1854. A note on the back records that this specimen was “Taken in a Spanish Frigate from South America”, perhaps as booty. Originally unlabelled, where and when the stem was cut is unknown. European governments with tropical colonies were keen to learn more about Cinchona and to break the South American monopolies on its biological products by establishing the trees in other parts of the world, especially India (the British) and Java (the Dutch). The sheet is a reminder of how the geographical distribution of economically useful plants has been utterly transformed by human activity. Coffee, tea, cotton, tomatoes, oil palm, and a host of other plants are now cultivated in situations far from the areas in which they first evolved. For every useful plantation established, however, natural biodiversity has been lost. It’s a difficult balance.
[email protected]
www.thelancet.com Vol 387 March 12, 2016
Object lessons The herbarium sheet Despite the power of synthetic chemistry, medicine still needs the natural products of plants. Plants are important as potential sources of new drugs. In the past they provided the raw materials for therapeutics. Using the correct kind of plant was important, since plants can poison as well as heal. But the species was also important. One common way of recording their identity and establishing permanent preserved specimens was with the herbarium sheet. This simple piece of paper held the dried and pressed plants parts, which could then be labelled with the name and place of origin. From the 16th century collections of herbarium sheets have been important components of botany. In some cases, herbaria provide the “type” specimen, the original example from which a new species is differentiated. As our world becomes more biologically impoverished, they are also a historical record of lost biodiversity. Herbaria offer a permanent legacy of the natural world that can be consulted long after the specimen was procured and preserved.
© The Board of Trustees of the Royal Botanic Gardens, Kew. Reproduced with the consent of the Royal Botanic Gardens, Kew
For more on Object lessons see Comment Lancet 2015; 386: 939 and Perspectives Lancet 2015; 386: 945, 1525, 1933, and Lancet 2016; 387: 113
*Bill Bynum, Helen Bynum Herbarium sheet for Cinchona officinalis
1046
These things matter for medicine. The herbarium sheet for Cinchona officinalis shown here comes from the Herbarium at the Royal Botanic Gardens Kew, in London, UK. The genus Cinchona contains some 23 species, but the biologically active bark is highly variable in the different species. Three species are especially rich in more than 20 active substances. This was known even before the alkaloids, of which quinine and quinidine are the most important, were isolated in the early 19th century. It was consequently essential that the right species was used, both in extracting the “bark”, as the medicine was long known, and in obtaining seeds for transplanting elsewhere. Its other appellations, Peruvian bark and Jesuit’s bark, hint at its early history. The inhabitants of western South America, where the trees are indigenous in the tropical Andean forests, used the bark as a febrifuge, whence the Spanish learned of it. The story goes that the Viceroy of Peru’s wife, the Countess of ChinchÓn, was cured of a fever in 1638. It probably wasn’t malaria, but the story took hold, and the bark was brought to the Old World in the early 17th century. Malaria was then common in much of Europe and demand for the new drug was high. Thomas Sydenham (1624–89) was so impressed with its power to root out the ague (mostly quartan malaria caused by Plasmodium malariae) that it stimulated him to argue that diseases could be classified just like plants and animals. A century later, Linnaeus named the tree’s genus and some of its species. He misspelled the Countess’s name, but, as is the custom of biological nomenclature, Cinchona became the perpetual name. The vagaries of botanical nomenclature (more than 330 names have been given to Cinchona) are seen at the bottom of this picture—all the names here are synonyms for C officinalis. This herbarium sheet was first dated in 1854. A note on the back records that this specimen was “Taken in a Spanish Frigate from South America”, perhaps as booty. Originally unlabelled, where and when the stem was cut is unknown. European governments with tropical colonies were keen to learn more about Cinchona and to break the South American monopolies on its biological products by establishing the trees in other parts of the world, especially India (the British) and Java (the Dutch). The sheet is a reminder of how the geographical distribution of economically useful plants has been utterly transformed by human activity. Coffee, tea, cotton, tomatoes, oil palm, and a host of other plants are now cultivated in situations far from the areas in which they first evolved. For every useful plantation established, however, natural biodiversity has been lost. It’s a difficult balance.
[email protected]
www.thelancet.com Vol 387 March 12, 2016