THE PHYSIOLOGY OF MUSCULAR WORK 219 



in its capacity to grasp with the hands and feet. Most interesting 

 observations have been made upon this subject ( 15 ), which affords 

 strong support for the Darwinian theory of evolution. Infants 

 at the very beginning of their separate existence possess a remark- 

 ably strong grip ; they can hang by their hands from a horizontal 

 bar and support their own weight, and the strongest may maintain 

 their position for two minutes. Most adults would find it difficult 

 to support themselves in this way for a quarter of the time. Infants 

 possess also a power of grasping with the foot ; the great toe is 

 abducted and the foot is held more in the position of a hand. This 

 power is gradually lost as the child grows up, and is only found 

 greatly developed in the adult in those rare cases of congenital 

 absence of the arms and hands. These prodigies may be seen at 

 fairs exhibiting their skill in using their feet for all the purposes 

 for which an ordinary man uses his hands. 



For these characteristics of the infant there appears to be 

 no adequate explanation except the one suggested by Dr. Louis 

 Robinson. He considers that they are examples of atavism ; that 

 the infant of primitive man was carried in a manner similar to that 

 seen in apes, the offspring clinging to the parent by grasping with 

 its hands and feet the hair under the arms and over the pubes. 

 Grasping their parents' hair is well known to afford infants their 

 earliest form of amusement. Dr. Robinson has also pointed out 

 that his view would offer an explanation of the great development 

 of hair over the pubes and in the axillae at the time of puberty. 



It is well known that the foetus often makes active movements 

 in the uterus ; these movements are known as " quickening with 

 child," and by one of those subtilties in which the legal mind 

 delights have acquired some importance, for they entitle any preg- 

 nant woman who is condemned to death to at least a temporary 

 reprieve. In many cases, however, no active movements may be 

 detected even in the last days of pregnancy. 



There is another striking example of muscular power and co- 

 ordination in the infant. Within a few seconds of its birth it 

 draws its first breath, and continues to ventilate its lungs by 

 alternate contraction and relaxation of its respiratory muscles, 

 although up to this time its respiration has been entirely carried 

 out by the placenta. Ahlfeld ( 16 ) maintains that this activity of 

 the respiratory muscles is not suddenly assumed at birth, but 

 that slight respiratory movements can be detected in the foetus 



