There is also a marked difference in the temper and habits of the two. The dog is, generally speaking, easily manageable, but nothing will, in the majority of cases, render the wolf moderately tractable. There are, however, exceptions to this. The author remembers a bitch wolf at the Zoological Gardens that would always come to the front bars of her den to be caressed as soon as any one that she knew approached. She had puppies while there, and she brought her little ones in her mouth to be noticed by the spectators; so eager, indeed, was she that they should share with her in the notice of her friends, that she killed them all in succession against the bars of her den as she brought them forcibly forward to be fondled. M.F. Cuvier gives an account of a young wolf who followed his master everywhere, and showed a degree of affection and submission scarcely inferior to the domesticated dog. His master being unavoidably absent, he was sent to the menagerie, where he pined for his loss, and would scarcely take any food for a considerable time. At length, however, he attached himself to his keepers, and appeared to have forgotten his former associate. At the expiration of eighteen months his master returned, and, the moment his voice was heard, the wolf recognised him, and lavished on his old friend the most affectionate caresses. A second separation followed, which lasted three years, and again the long-remembered voice was recognised, and replied to with impatient cries; after which, rushing on his master, he licked his face with every mark of joy, menacing his keepers, towards whom he had just before been exhibiting fondness. A third separation occurred, and he became gloomy and melancholy. He suffered the caresses of none but his keepers, and towards them he often manifested the original ferocity of his species. These stories, however, go only a little way to prove that the dog and the wolf have one common origin. [There are some naturalists that even go so far as to state that the different varieties of dogs are sprung from, or compounded of, various animals, as the hyaena, jackal, wolf, and fox. The philosophic John Hunter commenced a series of experiments upon this interesting subject, and was forced to acknowledge that "the dog may be the wolf tamed, and the jackal may probably be the dog returned to his wild state."