Human uses of mammals that "one is well advised to study the behaviour rather than attempting to get at any underlying emotion". Charles Darwin however had accepted the idea of emotion in animals, writing his 1872 book "The Expression of the Emotions in Man and Animals" on the subject. Darwin believed that mammals had social, mental and moral lives. In "The Descent of Man" (1871), he wrote: "There is no fundamental difference between man and the higher mammals in their mental faculties." Biologists remained wary of the idea, even for the great apes, but this led to serious difficulties, as Donald O. Hebb explained
The Man in a Case Man in a case" worked. The exact prototype of Belikov is unknown. Some contemporaries (including V.G. Bogoraz and M.P. Chekhov) considered that the teacher of Ancient Greek language and the inspector of the Taganrog gymnasium A.F. Dyakonov was a prototype of "the person in a case", others described the traits of character of Dyakonov disproving opinion of the first. So, P.P. Filevsky noted Dyakonov's generosity and wrote: "I positively claim that between "The man in a case" and A.F. Dyakonov there is nothing in common and no local color can be found in this work by A.P. Chekhov". The cost