906 Dynamic Theory. 



S. N. Rhoads, in American Naturalist for March, 1889, advances the 

 opinion that the songs of birds are founded on imitations of other sounds. 

 " The Mocking-bird, Catbird, Shrike and Jay, are studied and artistic 

 imitators of their feathered associates, indicating the perfection to which 

 bird language has developed as an art ; but if we would seek examples 

 of the primary instinctive exercise of the mimetic faculty, the notes of 

 the Prairie Bluewing and Yellow Warbler, the Grasshopper warbler of 

 Europe, the Yellow-wing and Savannah Sparrow, together with most of 

 those of the ardeidse, anatidse, rallidae, and some of the better known 

 strigidae and faliconidae, afford a better illustration. " Some of the above 

 closely mimic the noises of the insects in their neighborhood. The yel- 

 low-breasted rail imitates the croak of the tree frog. The bittern and 

 green heron imitate certain species of frogs, while the frog himself orig- 

 inally took his lesson from the rush of waters playing in and out of con- 

 fined places. The long and short billed marsh wrens and the winter 

 wren, sing in harmony with the noises of their aquatic surroundings, the 

 bubbling of moving water, and the "prattle of woodland rivulets." 

 1 ' The same may be observed of the dipper, kingfisher, aquatic thrush, 

 blue-yellow-back warbler, seaside finch, swamp sparrow, and others. " 

 The pteroptochos albicollis, a bird in Chili which stays about the bushes 

 on the barren hills, is called the Tapacolo," which means " cover your 

 posteriors." Its tail stands up more than erect, tilting over toward the 

 head. It is very sly and crafty. It has five different cries for different 

 times of the year, " some of which are like the cooing of doves, others 

 like the bubbling of water, and many defy all similes." ( Darwin.) 



Words which have been formed in imitation of sounds in the objective 

 world are called onomatopoetic, literally to make names. Obviously 

 only a part of a language can be onomatopoetic, since only a part of our 

 environment gives us sensations of sound. Expressions which convey 

 the ideas of the shapes, sizes, appearance and qualities of many things, 

 their states of motion and rest, &c. , can be produced by various gest- 

 ures, and are naturally so produced. Even now in the most highly 

 civilized communities, gestures are not entirely superseded by words, 

 though they are ordinarily used as accompaniments and emphasizers. 

 The western sheep ranchers educate a certain breed of shepherd dogs to 

 obey signal gestures, which are, however, simple and so natural as to be 

 easily taught to the intelligent dog. A beckon with the hand means 

 come, a repelling motion go, a wave of the hand to the right or left 

 means move in tho direction indicated. A dog at the distance of half a 

 mile or more will move as commanded by these signs, frequently stop- 

 ping and looking back for further instructions. There are many cases 

 on record of dogs, by natural gestures and physical demonstrations, so- 

 liciting the attention of their masters for a special purpose. In more 



