Much, has been written on Leeuwenhoek. It is with diffidence that I undertook to speak to-night on this subject in the country of Dobell and Cole, who have contributed so much to the knowledge and understanding of this great microscopist. Yet, though Leeuwenhoek's letters, written quite frankly like Pepys' diary, contain a self portrait more captivating than most autobiographies written for the purpose, the image deduced from them by most authors leaves me somewhat dissatisfied.