BABIES AND MONKEYS. 385 



elbow. Here, again, according to Darwin, rain has been the modi- 

 fying agent ; the habit of clasping the hands over the head dur- 

 ing rain has caused the rain to flow from the hands to the elbows, 

 and has given the hair direction in accordance. These, of course, 

 are " acquired characters " the lie of the hair is in accordance 

 with certain disposing forces of environment. Such causes do 

 not act on us now ; but there are no causes acting to the contrary 

 in a sufficiently potent manner. Consequently, we retain by the 

 conservatism of heredity a character acquired in response to the 

 necessities of environment in our prehuman ancestors. 



To return to the persistence of habit, the case of sucking may 

 be noticed. Sucking, of course, is the act of childhood it is one 

 of the most important incidents connected therewith. The baby 

 sucks to satisfy hunger ; and associated with sucking are the feel- 

 ings of warmth, sleep, and comfort. But hunger means distress ; 

 and sucking to satisfy hunger means sucking to alleviate a j^ar- 

 ticular distress ; consequently, it has developed into sucking to 

 alleviate any distress or pain generally. Thus, when an infant is 

 hurt, it turns in its distress to its mother ; it desires to suck, and 

 it forgets its trouble in sucking. All these associations are potent 

 in later life. It may be observed in many children long after 

 they have given up sucking ; when they are cross, or when they 

 are teased, or angry, and vexed, they suck their thumbs. Many 

 children in the same way can not go to sleep without sucking- 

 something their thumbs generally being ready implements for 

 the purpose so persistent is the association of sucking with sleep. 

 In later life children suck the ends of their pens or pencils when 

 in doubt and perplexity over their lessons, from the association 

 of sucking with distress or anxiety; and in still later life the 

 masher, and the young man whose ideas do not flow very readily, 

 suck the ends of their walking-sticks when they are in doubt or 

 anxiety, in conversational or amatorial matters such act of suck- 

 ing being a relic of the baby habit acquired by the infant from 

 the asssociation of sucking with alleviation of distress, no matter 

 in what way it was caused. Further, the number of men who 

 suck the ends of their mustaches,* and of women who suck the 

 ends of their crochet or knitting needles, or anything else, when- 

 ever they have the least feeling of doubt, annoyance, anxiety, dis- 

 tress, discomfort, or the like, points to the persistence of a youth- 

 ful habit long after all reason for it has ceased, and forms 

 an instructive lesson in the development of the methods used to 

 express emotions. 



In other animals equally curious habits may be noticed, par- 



* Apart from the sedative effects of nicotine, the sucking at a pipe may also be sooth- 

 ing from the inherited association. Some nonsmokers suck straws. 

 VOL. XLVI. 28 



