FIBRES OF THE INTERNAL CAPSULE OF THE BONNET MONKEY. 
59 
We say most of the excitable region, because the recent investigations of Schafer'^ 
show that on excitation of the occipital and angular gyri certain movements of the 
eyes are evoked, which, by reason of their greater latency of production, seem to be a 
result of secondary stimulation of the area for such movements situated in the frontal 
region.t Consequently, although this point is still greatly s'lib judice, it seems 
probable that the excitable fibres of the internal capsule only come from the fronto¬ 
parietal region. The course they take to reach the various points in the capsule will 
he determined by the anatomical relations of the cortical mantle to the basal ganglia, 
the exact lines of such courses, tliough not yet determined anatomically, may be 
theoretically imagined. 
We have ascertained the anterior and posterior limits respectively of the excitable 
fibres in each experiment, and have constructed the following outlines, see fig. 1 
(twice the natural size), showing the delimitation of these fibres in each group, the 
position of each point being determined by the averages given in Table I., see next 
page. 
III., IV., V. The Tempoml, Occipito-Temporal, and Occipital Fibres .—The 
delimitation of these fibres we have only in the present research ascertained by the 
process of exclusion, i.e., by their non-excitability. We believe that they have for 
the most part to do with the general and special senses, but the method of the 
present research does not throw any fresh light on the subject. 
It is, however, worthy of note that even in the narcotised state, when the scalpel 
divided these fibres at the hinder end of the capsule, there frequently occurred a 
marked general reflex movement. Excitation of the peripheral ends of these cut 
fibres produced, of course, no effect. 
* ‘ Roy. Soc. Proc.,’ vol. 43, 1888, p. 411. 
t Cf. also Sherrington’s very valnable anatomical confirmation of Schafer’s statements. ‘ Pro¬ 
ceedings of the Physiological Society,’ March, 1889. 
