The English Mastiff is a breed of large dog. Excessive running is not recommended for the first two years of the dog's life, in order not to damage the growth plates in the joints of this heavy and fast-growing dog, which in some weeks may gain over 5 lb. However, regular exercise must be maintained throughout the dog's life to discourage slothful behaviour and to prevent a number of health problems. Another important contribution to the breed was made by a dog called Lion, owned by Captain (later Colonel) John Garnier of The Royal Engineers. He bought two Mastiffs from the previously mentioned dealer Bill George. The bitch, Eve, bought by George at Leadenhall Market, was old enough to be grey-muzzled, but of good type.