Page:Popular Science Monthly Volume 34.djvu/52

42. The gopher is singularly exempt from the dangers encountered by the species which normally dwell on the surface, and its needs are totally different from its purely terrestrial kindred. How is it, then, that the form remains unchanged? Clearly the selectionist has to assume either that advantageous variations do not occur, or that there is some controlling element limiting the process of variation which absolutely prevents the accumulation of these chance modifications to a profitable end. Variations do occur in the shape of individuals. They seem to be about as plastic as other vertebrates in this regard. Here we must throw out the idea that the failure to produce advantageous modifications is due to the lack of variety on which selection can work. We are therefore reduced to the question-begging of which many naturalists now avail themselves in considering this process, and are compelled to say that there is a certain rigidity in the organization of the animal which prevents the accumulation of beneficial variations. This explanation is substantially like that of the doctor in Molière's play, who explained that "opium put people to sleep because of its soporific virtue"; but this does not suffice in the present case. It is worth while to note in this connection that, although the habits of the gopher have varied little with their peculiar habit of life, they have invented, as before noted, the very sufficient and ingenious custom by which they discharge the surplus earth from their burrows at the least expenditure of force and time. This peculiar intellectual adaptation appears to me one of the most interesting features connected with the life of this interesting animal.

To the question, sometimes raised, whether in the existing profusion of books and newspapers, making the direct taxing of memory less necessary than formerly, the powers of that faculty may not be depreciated, it may be answered that, though we no longer depend upon the memory as our only register of facts, we still use it more than the ancients did. Our knowledge travels over an immeasurably wider area, we have more to remember, and with continued advancement of civilization a good memory becomes more needful for the work of life. Our general intelligence and powers are improving, and memory is sharing in the general advancement.