852 



SCIENCE. 



[N. S. Vol. XI. No. 283. 



paratus of laughing, but because humor, 

 which is the commonest occasion of this 

 extreme manifestation, is not appreciated 

 earlier. It seems probable that the shock 

 produced by the sudden understanding of 

 the ' point ' of a joke has much to do with 

 the intensity of the reaction in this case. 



The practical perfection of the smile and 

 laugh (as of the expression of grief and pain) 

 at this very early period of life is a fact in 

 itself worthy of note, and serves to empha- 

 size both the universality of laughter in 

 man and its deep-founding in the organism. 

 When a few weeks old, or when even a few 

 months old commonly, the average infant 

 has not voluntary control enough over even 

 its most mobile members, the finger and 

 thumb, as to extend the latter into its 

 mouth, even when the child searches his 

 hand with his mouth with great eagerness 

 for some much desired projection, and that 

 even when it has been so extended for him 

 repeatedly. The contrast of such helpless- 

 ness with the innate perfection of the smile, 

 involving the simultaneous action of a dozen 

 or more muscles on each side of the face, is 

 a striking illustration of innate reflex func- 

 tion, and little less remarkable than the 

 mechanical actions of sucking and digestion 

 themselves. It seems indeed proper to 

 suppose that the nervous mechanism for 

 the ' control ' of so complex a set of move- 

 ments should be related to the deepest and 

 most basal opposition in which the muscles 

 are concerned, namely the functions of ex- 

 tension and of flexion, of increasing and of 

 decreasing respectively the general super- 

 ficies of the body. Imitation has clearly 

 little or nothing to do with the original 

 process of the smile, for many weeks after 

 the child can smile to perfection, he is 

 totally unable to imitate even the bending 

 of a finger although the simple act be per- 

 formed a huadred times before his eyes. 

 It must surely be judged that the smile is 

 wholly instinctive and in a sense reflex, a 



psychophysical characteristic of at least the 

 human young by the inherited law and 

 structure of its being. 



The biologic purpose and value of the 

 smile and laugh are not far to seek, not 

 much further indeed than are those of the 

 expression of grief and pain as the appeals 

 of the crying needs of the child to his 

 mother : both of these are obviously biolog- 

 ically protective and preservative . A glance 

 at the usefulness of the smile will show 

 what in part has made it so invariably an 

 aspect of the psychophysical life of man, 

 and, doubtless by imitation, perhaps of 

 some of the highest brutes. In the infant 

 the smile very early becomes the index of 

 the parental attitude toward him, and 

 hence, because of its great biologic interest 

 for his personality, he is apt instinctively 

 to become at a surprisingly early period 

 fairly learned in the physiognomy of the 

 smiling, as of the frowning, face. Again, 

 when the time has come in the course- of 

 nature that the young man acquires a 

 highly specialized interest in one of the 

 opposite sex, the smile becomes to a quite 

 characteristic degree the object both of ad- 

 miration and of further study. Later on, 

 in business life, the smile, as exponent of 

 the emotional attitude of those with whom 

 the struggle for existence puts the man into 

 some sort or other of competition, becomes 

 even commercially important, and when an 

 individual has profited so well by his long 

 subconscious study of smile physiognomy 

 that he can in general distinguish the nat- 

 ural or true smile from that of him who 

 can smile and smile and be a villain still, 

 his education in this direction may be called 

 complete. It is because the smile is normally 

 the indication of a pleased friendliness that 

 it plays so important a part in the serious 

 aflairs of social intercourse, as useful as such 

 to the schemer and the rogue as to the one 

 enjoying properly the pleasurable society of 

 his friends. 



