50 



OLOF LARSELL 



An attempt was made to analyze those roots which penetrate 

 into the brain, using the osmic-aeid material. The few roots 

 which were successfully isolated were of small size. They were 

 removed and mounted whole in glycerin. One or two myelin 

 sheaths were observed in each case, the remainder of the root 

 being evidently composed of unmyelinated fibers. They thus 

 resemble, except in size, the strands on the arterial walls. 



art.w. 



38A 



39B 



Fig. 38 A and B Motor terminations in muscular layer of anterior cerebral 

 artery of beef. A illustrates the typical appearance. B showed slight terminal 

 knobs. Gold-chloride technique. X 733. 



Fig. 39 A and B Sensory nerve terminations in wall of anterior cerebral artery 

 of beef, illustrating typical spindle-like outline and myelinated fibers. A repre- 

 sents a typical termination, B shows two smaller ones attached to a common 

 branch. Gold-chloride technique. X 733. 



Nerve terminations. The frozen beef brains responded well to 

 the gold-chloride treatment, and terminations of the twigs which 

 enter the muscular walls of the blood-vessels were found. These 

 nerve endings, as in the cat, are of two types. Type I (fig. 38, 

 A and B) consists of delicate varicosed fibers which ramify and 

 run for varying distances among the unstriated muscle cells. 



