104 THE POPULAR SCIENCE MONTHLY. 



The singing of mice has been attributed to various causes : 1. It 

 has been thought to proceed from disease of the lungs or vocal organs, 

 and to be akin to the wheezing characteristic of asthma. 2. It has 

 been propounded that the singers are always pregnant females ; but 

 this statement has been made on very insufficient data, and may, I 

 think, be dismissed. 3. Dr. Crisp informed Mr. Buckland that he 

 thought the singing was caused by a parasite in the liver; and Mr. 

 Buckland tells me that he has at his museum at South Kensingfton a 

 specimen in spirits in which this parasite is plainly visible in the liver 

 of a singing mouse once ahve in his possession. "But," he says, " I am 

 not at all sure that other mice also who are not musical have not this 

 parasite." This I believe to be the case, for it is well known that mice 

 and rats, whether singers or not, are peculiarly liable (perhaps from 

 their promiscuous feeding) to become the hosts of parasites such as 

 hydatids in the liver, and trichina in the muscles. 



Of course, I can say nothing about the condition of the livers of the 

 two mice I heard sing last week ; but they did not act as if they were 

 afflicted with disease of the liver, or any other organ. Brisk and viva- 

 cious in all their movements, darting now and then back to their hiding- 

 place, as if to keep open their means of retreat while foraging, they 

 looked the impersonation of vigorous health and bright activity ; and, 

 like every one else who has heard them, I feel quite sure that their song 

 — especially that of " Nicodemus " — is not involuntary, nor the result of 

 any disease of the respiratory organs, but an intentional and conscious 

 utterance of a series of notes in musical sequence. As Mr. Buckland 

 says {loc. cit.), " The song is a genuine song, as good and as musical 

 as that of a lark on a fine summer morning," 



Prof. Owen tells us that the anatomy of the mouse is very similar 

 to that of birds ; and all who have seen this little rodent in the act of 

 singing have noticed that the throbbing of its throat is like that of a 

 bird in full song, and that it then elevates its snout as a bird does its 

 beak. 



Whether the singing of mice may be due to an imitative faculty 

 which leads them to mimic the vocalization of birds, I am not prepared 

 to say. There is great apparent probability in favor of this supposition, 

 but there is, also, strong evidence against it ; because well-authenti- 

 cated instances have been adduced of mice bred in captivity, and apart 

 from any caged bird, having exhibited cajjability of song. 



It is remarkable that in almost every case of a singing mouse hav- 

 ing been seen as well as heard, it has been described as very small, 

 much browner than the common gray or slate-colored mouse, and as 

 having very large ears. This exactly applies to my little entertainers, 

 " Nicodemus " and " The Chirper." They are both very tiny mice, 

 their coats are very brown (not so much so as to be fawn-colored), and 

 their ears are abnormally big. I should be tempted to regard the 

 singing mouse as a peculiar variety, if this idea had not been contra- 



