REGENERATION OF PERIPHERAL NERVES 507 



Voischvillo ('83) studied the numerical relations of sensory 

 fibers to the skiri of the extremities and of motor fibers to mus- 

 cles which move rapidly and those which move less rapidly but 

 with great force. He found that the skin of the upper extremi- 

 ties was more abundantly supplied with sensory fibers than the 

 skin of the lower extremities, also that the eye muscle received 

 a greater proportion of nerve fibers to muscle fibers than the 

 muscles of the extremities. 



Vashkevitch ('87) determined the number of fibers in the n. 

 ischiadicus and n. medianus of bats, mice, rats, marmots, rabbits, 

 cats and dogs and found that the absolute number of nerve fibers 

 depended upon the weight of the central nervous system and 

 the weight of the body, but that the increase in number of fibers 

 does not progress at the same ratio with the increase in body 

 weight. 



Fritsch ('89) determined, in the torpedo the numerical relations 

 of the elements of the electric organ to the nerve cells and nerve 

 fibers. 



Dunn ('00) observed that practical equality exists in the num- 

 ber of fibers in the legs of the two sides of the frog. 



Dunn also ('02) showed by numerical determinations on the 

 nerve distribution in the frog's leg that the number of fibers 

 normally increases by branching as one passes distally. 



Hatai ('02) in a study of the ganglion cells and the dorsal 

 root fibers determined the ratio of nerve fibers to cells in the white 

 rat at 10.3 grams body weight and at maturity. 



Hatai ('03) also found that the rate of increase in the number 

 of fibers of the ventral roots of the spinal nerves of the albino 

 rat was most rapid between the body weights of 10.3 and 25.4 

 grams and that the number found at maturity is 2.7 times that 

 found in the 10.3 gram rat. 



Donaldson ('03) in considering the number of fibers distributed 

 to the skin and muscles of the frog's leg found that this dis- 

 tribution followed a fixed law expressed as follows: The nerve 

 fibers entering the leg of the frog (Rana virescens) by the sciatic 

 and crural nerves, are distributed to the thigh, shank and foot 



