In the same periodical, the following additional particulars as regards singing mice are presented by Mr George J. Romanes, Regent's Park.
'Several years ago I received some of these animals from a friend, and kept them in confinement for one or two months. The description which your correspondent gives of their performance leaves very little to be added by me, as in all respects this description agrees perfectly with my own observations. I write, however, to remark one curious fact about the singing of these mice, namely, that it seemed to be evoked by two very opposite sets of conditions. When undisturbed, the little animals used for the most part to remain quiet during the day, and begin to sing at night; but if at any time they were alarmed, by handling them or otherwise, whether during the day or night, they were sure to sing vigorously. Thus the action seemed to be occasioned either by contentment or by fear. The character of the song, however, was slightly different in the two cases.
'That these mice did not learn this art from singing birds there can be no doubt, for they were captured in a house where no such birds were kept. It may be worth while to add that this house (a London one) seemed to have been suddenly invaded, so to speak, by a number of these animals, for although my friend has lived in this house since the year 1862, it was only during a few months that singing mice were heard in it, and during these few months they were heard in considerable numbers.'
As corroborative of the foregoing notices, we give the following very interesting account of a singing mouse, obligingly sent to us by a correspondent, Mr Alfred Wright.
'In the early spring of last year I was invited by an old widow lady to see a singing mouse, which she had at night heard singing and scratching beneath the floor of her bed, and been so fortunate as to catch in a trap. I went, and found the little animal in a cage with a revolving wheel, similar to that in which a squirrel is usually confined. Whether the mouse was shy at the presence of a stranger, I do not know. It remained silent; but at length, after my patience had been nearly exhausted, it began to sing in clear warbling notes like those of a bird. When I called the next evening to hear the mouse again, I heard him to perfection; and was so filled with interest in the novelty, that I begged permission to bring any friend who was a sceptic of the fact, or who might desire to see the phenomenon. My request was readily granted. One friend of course had heard of a singing mouse, but he certainly would not allow that a prolonged squeak was a song--not he! Another friend of course had heard a mouse sing when he was a boy; but he was told, he perfectly well remembered, that the _noise_ produced by the mouse was the result of some internal disease. Well, both of these went with me to hear the little creature. Unfortunately, at first it was again shy; but after an interval of silence it commenced to sing--sweetly, like the low notes, the jug, of the nightingale. My friends had come, had heard, and were conquered! The one acknowledged it was really a song and not a squeak; the other, that the noise was certainly dulcet; but still he thought it possibly might be the result of disease, and not natural to the little animal. We suggested that this wonderful natural curiosity (as we deemed it) should be sent to an eminent naturalist who resided near. Great, therefore, was my astonishment and pleasure when it was presented to me, who could only treat it like a schoolboy would his white mouse--as a pet. And truly it became a great pet to both my wife and myself.