has scarcely been investigated. As a curiosity, yet as a possible venture, a parallelism may be suggested between the stridulations of a cricket, which have been counted as occurring at the rate of between two and three chirps per second[1] and the number of pulse waves peculiar to very active insects or one hundred and fifty closures of the heart valves in one minute.[2]
Inspecting in a very cursory manner the higher phylums of the animal kingdom, the authority of numerous investigators can be given for the perfect rhythmic quality of bird songs. The writer can vouch for it that the cackle of one guinea hen during an entire summer went with clock-like regularity at the rate of eighty-eight to ninety-two cackles per minute. The faster cackling being a laughably accurate sign of the growing excitement attendant on the laying of an egg, said by the owner to occur at about eleven o'clock every morning.
The scientific study of rhythm, so far as man is concerned, has been approached almost wholly from the side of its conjunction with literature. Looked at from that side, it is not strange that the testimony could never be mathematically exact and emphatic. The only data which are of sufficient accuracy to prove that the rhythmic phenomena of pulse first impressed on our consciousness that which can accurately be called rhythm, are to be found in the metronomic denotations of musical compositions. It is there and there only that the brain has been able systematically to externalize the rhythm most natural to it with a sense of method and order approximating instrumental exactitude and capable of an exact expression and measure in number. These furnish only a trace, but a trace sufficient when one keeps in mind the havoc that conscious intellect can always play with things strictly natural.
While making a bibliographical search for anything treating of this musical side of the subject, one suggestive title only was found. It was under 'pulse' in the Larousse Encyclopedia and covered the subject to a degree alarming to a new and anxious investigator. It 'Nouvelle methode facile et curieuse pour connaître le pouls par les notes de la musique.' (New method, easy and curious for gauging the pulse by musical notes.) François Nicolas Marquet, Nancy, 1747. When found, the quaint little book proved lamentably insufficient. In its time there was neither metronome nor sphygmograph.
In the introduction to this little treatise which in its day seems to have created quite a stir—'amateurs in search of novelties bought it for fun, and kept it by good taste,' M. Marquet naïvely tries to disarm his critics by saying that he already seemed to hear them object: 'it is certainly a very bizarre matter this learning to know the pulse by musical notes,' adding, 'one could answer them, it is not more strange
