In 1815 appeared the first part of the 'History of the British Crustacea' entitled Malacostraca Podophthalma Britanaica.' Seven teen numbers containing forty-seven plates only appeared. It is to be regretted that any circumstances should have precluded from completion a work that, even in its imperfect state, has become a standard in natural history. At different times Leach was elected Fellow of all tho more important societies in Europe and America, and communicated a largo number of papers to their various Transac tions. He was also author of the article on Carcinology in the Die tionnaire des Sciences Naturellee,' and in '31elanges Zoologiquee.' Independent of the desire of knowledge, a love towards the animals themselves formed a marked feature in his character, which induced a reciprocal feeling in those he potted, exhibited in the power to tame the most savage beasts or poisonous viper, with either of which he would play with impunity. It was his constant habit at one time to have with him a wolf of very ferocious temper, but which always obeyed and followed him in his walks about the city, and, on one occasion while in Paris it remained waiting for three hours at tho entrance of the Jardin des Plaates, with the fidelity of a common dog, while its master went into the grounds.
Leach was of a thin spare figure, and possessed an intelligent and expressive countenance, which was improved by a pair of most piercing black eyes ; his manner was engaging, aad his conversation earnest and convincing, aud when on the subject of hie favourite studies, enthusiastic. The result of this temperament was manifest
in the unwearied industry at his labours. Late at night and early in the morning-Leach was always to be found at work, and about the year 1817 he was often not in bed for the night. The consequence of his severe labours exhibited itself first in the injury tho use of the microscope entailed upon his sight, which induced ismaurosis. This in a short time was followed by a more serious illness, which precluded him from pursuing, except at irregular intervals for amusement, what had been the ambition of his life. He therefore retired from the curatorship of the natural history department of the British Museum and with it closed his scientific career.
He returned to the neighbourhood of Plymouth, where he continued until 1826, when he proceeded to the south of Europe. During his sojourn in Italy he industriously collected the insects of the localities in which he resided. The collection is preserved is the Museum of the Plymouth Institution and Devon and Cornwall Natural History Society. Although benefited by the warm climate of the south, his health never recovered from the shock his constitution ha I sustained, and when the cholera visited Europe he was among its early victims. Dr. Leach died August 25th, 1836, at St. Sebastiano in Piedmont.