A very interesting and romantic history might be written about the effect of drugs, dyes, and spices in developing trade. During the time when Britain was struggling to obtain a share of the foreign trade of Holland and France, such spices as Clove, Cinnamon, and Pepper were of the greatest importance. The Dutch, especially, adopted every possible method to keep the spice trade in their own hands. They cut down the clove, cinnamon, and other trees, in all the islands not directly under their control. They imposed the most barbarous penalties on any interloper. For instance, any one who sold a single stick of cinnamon in Ceylon was punished with death. When the English captured the island in 1796, all such restrictions were of course repealed. Nevertheless its cultivation remained a monopoly of the East India Company until 1832.
Logwood (Haematoxylon campechianum) is closely connected with the story of adventure and colonisation in the West Indies. Its use was at first forbidden by Queen Elizabeth as it did not yield fast colours; this was because the dyers of those times did not know of any mordant to fix them. Yet this is one of the few vegetable dyes which retain their position in the market in these days of aniline colours, and it is said to be a large constituent, with brandy, of cheap "port wine."
Indigo was known to the Romans, who imported it from India on camel-back by way of the Persian and Syrian desert. In the fifteenth century, when the Dutch began to introduce it in large quantities, it was found to interfere with the "woad"6 (Isatis tinctoria) which was then a very important cultivated plant in Europe. In Nuremberg, an oath was administered once a year to all the manufacturers and dyers, by which they bound themselves not to use the "devil's dye," as they called Indigo. Its more recent history shows a very different system. In Assam and other parts of British India, enormous sums of money have been invested in indigo plantations. It has been estimated that four million pounds was invested, and that a population of something like 700 Europeans and 850 workmen to the square mile in Behar, were entirely supported by indigo plantations.
Now all these planters are ruined and the population is dispersed, because German indigo manufactured from coal-tar is destroying the sale of the British-grown material. The plant has pretty blue flowers and belongs to the Leguminous order. The dye is obtained by steeping the leaves and young branches in water, and it is finally turned out in blue powder or cakes.
Perhaps the most interesting of all these drugs is Pepper. The Dutch, in the days of Queen Elizabeth, had a monopoly of the East Indian trade, and they tried to cut down or burn all spice trees except those in their own control. They could thus form a corner in pepper, and alter the price as they felt inclined. At one period they doubled the price, raising it from three shillings to six shillings per pound. This annoyed the London merchants so much that they met together and formed the "Society of Merchants and Adventurers trading to the East Indies." This was of course the original source of our great East Indian trade, and later on resulted in the Indian Empire.
At present, and for centuries past, the whole world is searched and explored for drugs and spices. Our medicinal rhubarb for instance, grows in China on the frontiers of Tibet; it is carried over the mountains of China to Kiaghta in Siberia, and from thence taken right across Russian Siberia to London and New York. It is closely allied to the common or garden rhubarb, which grows wild on the banks of the Volga.
It is only our duty to remember with gratitude all those long since departed botanists who have made our life so full of luxury and have supplied our doctors with all kinds of medicines.
The first doctors were of course just savage botanists, but as soon as men began to write down their experiences, we find botanical treatises. The first, and for a very long time the only, botanical books were intended to teach medical students the names and how to recognize useful flowers and drugs.
Medicinal herbs such as mandrake, garlic, and mint are found described on those clay cylinders which were used in Babylon instead of books, about 4000 B.C., that is some 6000 years ago! The Egyptians thought that "kindly, healing plants," such as opium, almonds, figs, castor-oil, dates, and olives, were derived from the "blood and tears of the gods"; that would be about 3000 B.C. It is not known how far back Chinese botany can be traced, but, by the twelfth century before Christ, some three hundred plants were known, including ginger, liquorice, rhubarb, and cinnamon.
Theophrastus, who flourished about 300 B.C., was a scientific botanist far ahead of his time. His notes about the mangroves in the Persian gulf are still of some importance. It is said that some two thousand botanical students attended his lectures.7 It is doubtful if any professor of botany has ever since that time had so large a number of pupils. Dioscorides, who lived about 64 B.C., wrote a book which was copied by the Pliny (78 A.D.), who perished in the eruption of Vesuvius. The botany of the Middle Ages seems to have been mainly that of Theophrastus and Dioscorides. In the tenth century we find an Arab, Ibn Sina, whose name has been commemorated in the name of a plant, Avicennia, publishing the first illustrated text-book, for he gave coloured diagrams to his pupils.
After this there was exceedingly little discovery until comparatively recent times.
But Grew in 1682 and Malpighi in 1700 began to work with the microscope, and with the work of Linnæus in 1731 modern botany was well started and ready to develop.8
It is interesting to compare the numbers of plants known at various periods, so as to see how greatly our knowledge has been increased of recent years. Theophrastus (300 B.C.) knew about 500 plants. Pliny (78 A.D.) knew 1000 species by name. Linnæus in 1731 raised the number to 10,000. Saccardo in 1892 gives the number of plants then known as follows: —
9. Saccardo, Atti d. Congresso, Bot. Intern. di Genova, 1892.
But, during the years that have elapsed since 1892, many new species have been described, so that we may estimate that at least 200,000 species are now known to mankind.
But it is in the inner meaning and general knowledge of the life of plants that modern botany has made the most extraordinary progress. It is true that we are still burdened with medieval terminology. There are such names as "galbulus," "amphisarca," and "inferior drupaceous pseudocarps," but these are probably disappearing.
The great ideas that plants are living beings, that every detail in their structure has a meaning in their life, and that all plants are more or less distant cousins descended from a common ancestor, have had extraordinary influence in overthrowing the unintelligent pedantry so prevalent until 1875.
Yet there were many, not always botanists, of much older date, who made great discoveries in the science. Leonardo da Vinci, the great painter, seems to have had quite a definite idea of the growth of trees, for he found out that the annual rings on a tree-stem are thin on the northern and thick on the southern side of the trunk. Dante10 seems to have also understood the effect of sunlight in ripening the vine and producing the growth of plants (Purgatorio, xxv. 77). Goethe seems to have been almost the first to understand how leaves can be changed in appearance when they are intended to act in a different way. Petals, stamens, as well as some tendrils and spines, are all modified leaves. There is also a passage in Virgil, or perhaps more distinctly in Cato, which is held to show that the ancients knew that the group of plants, Leguminosæ, in some way improved the soil. I have also tried to show that Shelley had a more or less distinct idea of the "warning" or conspicuous colours (reds, purples, spotted, and speckled) which are characteristic of many poisonous plants (see p. 238).
But if we begin with the unlettered savage, one can trace the very slow and gradual growth of the science of plant-life persisting all through the Dark Ages, the Middle Ages, and recent times, until about fifty or sixty years ago, when a sudden great development began, which gives us, we hope, the promise of still more wonderful discoveries.
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