188 BULLETIN NO. VII. 
and with great caution, and had the pleasure of seeing him sit- 
ting among his corn and singing his beautiful solo. I observed 
him without interruption, for ten minutes, not over four feet 
from him. His song was not a chirp, but a continuous song of 
musical tone, a kind of to-wit-to-wee-woo-woo-wee-woo0, quite 
varied in pitch. While Iobserved him I took for granted that 
he was a common house mouse (Jus musculus), but when he 
sprang from the shoe to make his escape he appeared like the 
prairie mouse (Hesperomys michiganensis), a species I had not 
however, observed before indoors. I have thus far failed to 
secure this little rodent musician, but I shall continue to do all 
I can in the way of popcorn to entertain him, and if his marvel- 
ous voice gives him the pre eminence in mousedom which he 
deserves, by the aid of natural selection I shall presently have 
a chorus of mice; in which case you shall receive their first 
visit.—W. O. Hiskey, Minneapolis, Minn.” 
The writer has been informed of many similar cases, making 
it certain that the musical performances described above, are in 
no way exceptional, but showing that considerable musical 
powers are universal among Hesperomys. That the song is 
not a voluntary expression of pleasure has been suggested by 
many. The most recent data in favor of the pathological 
nature of mouse music has been offered by Mr. Davis.* 
While wandering about the house its tell-tale song gave 
notice of its wanderings. ‘‘When removing it from the trap 
to the cage, and many times afterward, it ran about a small 
room, and the most noticeable feature on these occasions was 
the unvaried song, it being especially loud if I caused the mouse 
to scamper around the room several times without stopping. 
When gnawing upon the exposed wood in the cage, when eat- 
ing, or when disturbed in its nest, this singing was particularly 
loud; in fact, upon any exertion, the song was produced, vary- 
ing in volume in proportion to the amount of exercise.” 
‘*It was just previous to, and for some time after the birth of 
two miserable little young that J/us sang most continuously.” 
It would be of great interest to determine by anatomical 
examination whether the singing mice are suffering from bron- 
chial disease. 
*Wm. T. Davis. The Song of the Singing Mouse. Am. Naturalist, 1889, p. 481. 
