Of all the attributes of man which have been considered sufficiently distinctive to separate him from the lower animals, that of speech has been regarded as of the first importance. It has been looked upon as so essentially dependent upon human intelligence as in itself to constitute a sufficient line of separation between man and all living creatures below him. By none has this position been more strongly upheld than by Max Müller, who maintains that speech is a faculty of man which distinguishes him from all other creatures. This, of course, is true in a general sense; but as every attribute of man is at the present time undergoing a more complete analysis than has ever before been attempted, the dictum may be found not to be so absolutely correct, as at first sight appears; for it may be remembered that the subject of language has hitherto been treated by scholars and men of letters, who have discussed its various forms in relation to a given basis, whereas, at the present time, an endeavour is being made to proceed a step further towards the origin of language by its investigation from a physiological or scientific standpoint. If this be done, and we study the nature of language, as observed in the savage or the infant, we may perhaps discover that it is not altogether so different from what we may call the language of the lower animals. There is so much in man which is common to the creatures below him, that it is impossible to discuss rightly many of his propensities, affections and passions, without considering the form or character which these take in similar organisations. It is not surprising, therefore, that the subject of language should have been made a debating ground for the discussion of the points of difference between man and animals.