THE ARREST OF THE BODY. 101 



Passing over a multitude of intermediate forms, 

 watch, in the next phxce, the Hand of an African 

 Monkey. Note the great increase in usefuhiess due to 

 the muscuhir arm upon which the Hand is now 

 extended, and the extraordinary capacity for varied 

 motion afforded by the threefold system of jointing 

 at shoulder, elbow, and wrist. The Hand itself is 

 almost the human Hand ; there are palm and nail and 

 articulated fingers. But observe how one circum- 

 stance hinders the possessor from taking full advan- 

 tage of these great improvements, — this Hand has no 

 thumb, or if it has, it is but a rudiment. To estimate 

 the importance of this apparently insignificant organ, 

 try for a moment without using the thumb to hold a 

 book, or write a letter, or do any single piece of man- 

 ual work. A thumb is not merely an additional 

 finger, but a finger so arranged as to be opposable to 

 the other fingers^ and thus possesses a practical efiicacy 

 greater than all the fingers put together. It is this 

 which gives the organ the power to seize, to hold, to 

 manipulate, to do higher work ; this simple mechan- 

 ical device in short endows the Hand of intelligence 

 with all its capacity and skill. Now there are ani- 

 mals, like the Colobi, which have no thumb at all ; 

 there are others, like the Marmoset, which possess the 

 thumb, but in which it is not opposable ; and there 

 are others, the Chimpanzee for instance, in which the 

 Hand is in all essentials identical with Man's. In the 

 human form the thumb is a little longer, and the 

 whole member more delicate and shapely, but even 

 for the use of her highest product, Nature has not 

 been able to make anything much more perfect than 

 the hand of this anthropoid ape. 



