Phonetics, literally, are the enunciation of the principles upon which the production of sound depends; but the term is generally applied to those principles which govern the production of articulate human speech. Attempts have been made to establish the fact that articulate speech obtains among animals other than men, but they have not resulted in any positive evidence of this. In one sense phonetics are a branch of physiology, since speech is the resultant of breathing processes modified by the conditions of the larynx, tongue, and mouth, and nasal spaces. Some have considered that speech so modifies some of these parts that an examination of them would go far to determining to what race, or at least to what group of languages, an individual belongs by descent. It is chiefly as an aid to philological discoveries that phonetics have a practical value. The term phonetic is also applied to a system of spelling the object of which is to reproduce in letters the exact sound of words, and this use of phonetics has many supporters, especially among those who have to do with shorthand. This mode of speech is illustrated by printed organs and magazines, whose repulsiveness to the eye goes far to render any wide spreading of the system unlikely.