Letter, from Antoni van Leeuwenhoek to the Royal Society, dated at Delft Signed autograph Stating that balsam, if rubbed onto the chest, cannot pass into the lungs; account of apparatus, designed by Leeuwenhoek, to inhale smoke and vapour; observations of the blood vessels in a sheep's lung; observations of Leeuwenhoek's phlegm; theory that cold air can harm the lungs 3 red-chalk figures attached Read to the Royal Society on 25 March 1702 English translation see EL/L3/43 Transcribed and translated in 'Alle de brieven van Antoni van Leeuwenhoek', edited, illustrated and annotated by Committee of Dutch Scientists, vol 14, p 75 English translation printed in 'Philosophical Transactions', vol 23, no 279, p 1143 14 February 1702