VASCULARITY IN THE NERVOUS SYSTEM 447 



a mere glance at the table shows the striking fact that the sensory- 

 centers are more richly supplied with blood-vessels than are 

 those of which the function is motor, except in the single case 

 of the substantia gelatinosa Rolandi of the spinal cord. 



Among the motor centers upon which observations were made, 

 the poorest is the motor nucleus of the facial nerve, the richest 

 the ventral cornu of the spinal cord. The richest of the sensory 

 centers studied, on the other hand, is the dorsal cochlear nucleus, 

 while after it come, respectively, the chief vestibular nucleus, 

 the dentate nucleus, and the granular layer of the cerebellar 

 cortex. It will be noticed that the last three mentioned are 

 related to each other, and it may be remarked that these four 

 richly vascularized regions are ones which are probably in more 

 or less constant receipt of stimuli, and so may be assumed to 

 be in almost continuous activity, which may decrease in intensity 

 at times, but in all probability ceases more rarely than does the 

 activity of many other centers. It is interesting to observe that 

 even the molecular layer of the cerebellar cortex, though distinctly 

 poorer than the granular layer, is more richly supplied with capil- 

 laries than the motor, and even than some of the sensory centers. 

 Krause (loc. cit.) remarked that the inferior olive and the dentate 

 nucleus are conspicuous in their respective regions on account 

 of their richness in capillaries. The relative vascularity of the 

 various regions studied is shown graphically in chart 2. 



The present data correspond fairly well with the rather in- 

 definite statement of Hoche (loc. cit.) regarding the relative 

 vascularity of gray and white matter in the spinal cord. They 

 do not, however, agree with his statement that part of the dorsal 

 funiculus is the richest part of the white matter in the dog, nor 

 with Krause's findings on the relative richness of the white 

 columns in the human cord; the results of the present study 

 indicating that in the rat the pyramidal tract and the lateral 

 funiculus are richer than the ventral funiculus and the fasciculus 

 cuneatus, which are about alike. 



, - The pyramidal tract in the rat is situated in the ventral portion 

 of the dorsal funiculus of the spinal cord, where it is rather sharply 

 marked off from the rest of the white matter. It stains distinctly 



