170 PHYSIOLOGY OF CENTRAL NEEVOUS SYSTEM, 



cross in the cord and pass upward in the anterior funicuK. To 

 summarize, therefore, we may say that the evidence at hand 

 proves that the ascending fibers of the posterior funicuH do not 

 convey impulses of pain or temperature, that if they convey 

 any cutaneous touch (pressure) impulses, they certainly do not 

 form the only path of conduction for this sense, and that most 

 probably their chief function is the conduction of impulses of muscle 

 sense, — that is, they consist of those deep sensory fibers from the 

 voluntary muscles, the tendons, and the joints, through which we 

 obtain an idea of the position of the limbs and the state of con- 

 traction of the muscles. The sensations thus aroused in the higher 

 parts of the brain are necessary to the proper co-ordination of the 

 movements of the muscles. Injury to these funiculi, therefore, 

 while it does not cause paralysis, is followed by disorderly— that 

 is, ataxic — movements. On the histological side it has been shown, 

 as stated above, that these fibers end in nuclei of the medulla, 

 and thence are continued forward by the great sensory tract 

 known as the "lemniscus," to end eventually in that part of the 

 cortex of the cerebrum designated as the area of the body senses. 

 Ascending (Afferent or Sensory) Paths in the Lateral Funiculi. — 

 The two best known ascending tracts in these funiculi are those of 

 the cerebellospinal and the superficial anterolateral fasciculi. Both 

 of these tracts are composed of endogenous fibers (Fig. 77a). The 

 former takes its origin in the lower thoracic region, and is com- 



Fig. 77a. — Schema to indicate the mode of formation of the tracts of Flechsig and of Gower 

 and the connection with the posterior root fibers. 



posed of axons connected with the tract cells of the dorsal nucleus. 

 The impulses which its fibers convey are brought into the cord 

 through those fibers of the posterior root that end around the cells 

 of the dorsal nucleus. A number of the fibers in this funiculus end 



