Henrik Gahn explains why he has not answered Linnaeus’s letter [this letter has not come down to us] earlier; quite simply there has been nothing interesting to relate. Gahn also feels that he must explain to Linnaeus why he declined to join Daniel Solander’s next journey. The real details Gahn cannot put in writing, but will tell Linnaeus when they next meet. However, for the time being it would be enough to say that Solander’s happiness was entirely in the hands of Joseph Banks. Solander cannot even feed himself with his salary from the Museum [the British Museum], and has received not the slightest encouragement from King or Government, but everyone is interested in hearing his stories and therefore desire his company. What benefit would it have been to Gahn if he had only been Solander’s assistant, with the task of looking for natural history specimens and drying plants? Gahn reflects that with medicine in Stockholm he would not become rich but with natural history he would starve to death. In England there are no more openings, as here they reflect less on foreigners than anywhere else.
Gahn has, as requested, passed on Linnaeus’s greetings to Solander and reports that Solander has promised both John Ellis and Gahn that he will soon pass on his discoveries to Linnaeus. When Gahn first came to England he had heard that the recently returned travellers were planning to visit Sweden and place their spoils at the feet of Linnaeus, but since they had decided on a rapid return to the South Seas Gahn had heard that they had hoped that Linnaeus would come to England, and that Banks had promised to meet Linnaeus in Hamburg. Gahn wonders if this is true. Solander and Banks have employed Andreas Berlin, who had defended a thesis on usu fungorum [Gahn means Dissertatio academica usum muscorum], to prepare fair copies and to put in order their descriptions. Gahn supposes that a copy will be sent to Linnaeus. Berlin wishes to join the next expedition but Solander does not want him on account of his poor health. It is a pity that their first discoveries will not be published before they start on their second journey. They have drawings and descriptions of everything but not finalized and anyway so expensive to engrave and print that Gahn is certain that should Banks die everything would simply be forgotten. Gahn had asked Solander about the muscot, but he denies having seen it. At Ellis’s Gahn had seen two large dried muscot leaves with fruits that had been sent to him from Tobago in the West Indies. However, there was no flower. They were very similar to the figure in Georg Eberhard Rumpf, [Gahn refers to Herbarium Amboinense ] and from an incomplete description that accompanied them Ellis thought that they were Dioecia monandria monogynia. Gahn had seen the fruit; it was a capsula monosperma that opens along one of the sides, with the muscot flower enveloping the nut itself. Gahn thought it was remarkable that it had not the slightest smell or taste of Tobago. He had an English acquaintance, recently returned from Bengal, who had found muscot nuts on an island not far from there that were just like Rumphi’s description but without taste. Gahn’s acquaintance thought that the explanation was to be sought in defective male flowers. Already two years ago Ellis had written to ask for flowers of the tree but had not yet received them. Gahn thought that Ellis would write to Linnaeus on the matter, also saying that Ellis was a fairly kind and lovable person who also loved Linnaeus despite the fact that Ellis was dissatisfied that Linnaeus has supported Philip Miller in the dispute over Rhus vernix [Gahn refers to a dispute between Ellis and Miller in the Philosophical Transactions, see for example articles by Miller, “Remarks upon the Letter of Mr. John Ellis, F.R.S. to Philip Carteret Webb”, and by Ellis, “An Answer to the Preceding Remarks”, both published in 1758, and preceeding articles; see also Miller to Linnaeus, 20 January 1768{L4021}]. Gahn is almost certain that Ellis was right. The correct Rhus vernix as drawn by Engelbert Kämpfer is far different from the North American Poison as described by Johann Jacob Dillenius and drawn by Leonard Plukenet, as mentioned by Linnaeus. Among Kämpfer’s plants in the Museum there is a specimen of the right one, which has round leaves with pronounced veins, whereas the American has lanceolate and glabrous leaves with few veins. Kämpfer’s is a large tree, the other a bush; the former yielding strong resin and the latter no more than others of that genus. Kämpfer’s wild Rhus, or Fasino-ki, is also a different species; even those in the gardens here are yet another that they call sinense. They are of all colours, including black. Miller also included Mark Catesby’s Toxicodendron to the same species, which is even more widely different. Gahn remembers that Ellis had shown him several pieces of genuine Copal, together with the plant’s flower and fruit from which they were taken, and that was the correct Hymenaea. Ellis had also given Gahn some specimens of Brownea, which were to be sent without delay to Linnaeus. As Nicolaus Joseph, baron von Jacquin’s sketch was so incomplete, Gahn has taken the liberty of sending one he had done himself in all haste, and explains it thoroughly. A person named Young, who had sent the plant to Ellis, states that on the island of Tobago it generally has 9 stamens whereas in Nova Grenada it has from 10 to 12, which probably explains the reason behind the difference between Pehr Löfling and Jaquin. Gahn believes that Linnaeus has heard that the tea tree in the Duke of Northumberland’s garden at Sion had flowered during the autumn, which provided the reason for an artist and semi-botanist, Johannes von Müller, to make a drawing. The same Miller has started to publish an illuminated table and description of each class and order of Linnaeus’s System [An illustration on the sexual system of the Genera plantarum of Linnaeus], which will make the basic rules easier to understand. Miller told Gahn that he is only waiting for a suitable vessel in the spring to send the published work to Linnaeus. Another German, Johann Reinhold Forster, has also started to work with natural history, and is an industrious and kind man. He has published in English the Linnaean disciples’ travels [Forster had published a translation of Pehr Löfling’s, Iter Hispanicum, eller resa til spanska länderna uti Europa och America, called "An abstract of the most useful and necessary articles mentioned by Peter Loefling"], printed catalogues on North American naturalia [ Americae septentrionalis] and a work of new English insects [Novae species insectorum ], of which he will send everything with the first available vessel to Linnaeus. Gahn also wishes he could report something on Solander’s discoveries, since Solander himself takes such a long time, but knows too little about them. Gahn tells Linnaeus that a short report on the journey has been published in Carl Christoffer Gjörwell’s Almänna Tidningar which should amuse him. Their bread tree is monoecious but because only the sweet pulp, but not the seeds, are tasty, it is remarkable how the inhabitants cultivated some trees with sterile male flowers and have exterminated all the others, so that no seeds could be obtained in the entire country, and planting is done only with cuttings. On New Zealand, a plant, Liliacea, is used to make fine flax and woven materials. Gahn hopes that the master himself will soon be able to provide better information on all this. Gahn continues, mentioning the green powder that comes from the East Indies and makes a tasty jelly that Linnaeus knows was obtained from the leaves of Sassafras. In London, they have recently started to sell a similar white one, originating from North America and making a tasty jelly, much better than sago. Gahn suspects that it is made out of potatoes. The remarkable elastic resin that is made in the West Indies, used by the Chinese in ad titilationem in coitu augendam, is certainly included in Linnaeus’s collection. Gahn believed that a gentleman from the West Indies had told him how to make it. It is the juice of the ordinary fig, which, through a Convolvulus additive, precipitates this resin. Gahn is still unaware of the species of Convolvulus, and believes it to be new. A chemist in Paris, Pierre Joseph Maquer, has found that ether is the only menstruum for this resin. In addition to its many other uses it is used in London to remove lead pencil drawings and other dirt from paper and is much better, and more convenient, than wheat bread. Gahn has no other news concerning natural history, and apologises for taking up so much of Linnaeus’s time. At present, Gahn is fully engaged with medicine and hospitals. Gahn reports that William Hewson and Alexander Monro II in Edinburgh had almost simultaneously discovered the lymphatic vessels of birds, fish and amphibians. It would take too long to describe all the experiments that were made to confirm this, writes Gahn. The chemist Joseph Black in Edinburgh, had become so famous through his Aër fixus that he had now started another system on heat and cold. Gahn gives an explanation. Gahn again apologises for having certainly exhausted Linnaeus.
Gahn sends his greetings to Linnaeus’s wife [Sara Elisabet Linnaea] , the young professor [Carl Linnaeus the Younger] and the young daughters [Sara Christina Linnaea, Sophia Linnaea] . He also greets Jonas Sidrén, Gahn wrote to him a year ago from Göttingen, and wonders if he ever received his letter.
P.S. Gahn wants to know if if the Lopeziana and Colombo ever reached Linnaeus. He has seen in London how effective the Lopeziana is when curing diarrhoea. If Linnaeus would like to answer, Gahn thinjs it would be best to send it to his brother Walther Gahn.