10 Proceedings of the Royal Physical Society. 
In 1861 Dr Paul Broca published the first of a series of 
papers, “Sur le Siége de la Faculté du Langage articulé,” in 
which he demonstrated, from clinical and pathological observa- 
tion, the fact that the centre for speech was situated in the 
posterior part of the inferior frontal convolution. In cases 
of a lesion in this part of the cortex the patient cannof give 
articulate expression to the object he desires or is requested 
to name, although he may know the proper word-symbol for 
it. In 1869 Dr Hughlings-Jackson, from observations of 
cases of unilateral and localised epileptiform convulsions, 
came to the conclusion that there were motor centres in 
the cortex, the irritation of which caused the convulsive 
phenomena. 
The views of Hughlings-Jackson were soon confirmed and 
greatly extended by the experiments of Hitzig and Fritsch 
in Germany, and Ferrier in this country. In 1870 Hitzig 
and Fritsch published an account of their experiments on 
the lower animals, in which portions of the exposed brain 
cortex were stimulated by a continuous current, when the 
phenomena of contraction of certain groups of muscles was 
observed. on opening and closing the current.. In 1873 
Ferrier, to test the views of Hughlings-Jackson, undertook 
a somewhat similar series of experiments, using, however, a 
Faradic instead of a continuous current. He mapped out 
upon the cerebral cortex of the macacque monkey a large 
number of centres, each of which, on stimulation, was 
followed by certain definite movements. 
From experiments on various animals, it has been shown 
that this localisation becomes more definite as we pass 
from lower to higher forms, Thus it is hardly recognisable 
in the frog, and gradually becomes more distinct in the 
bird, rabbit, and dog. The macacus shows a decided advance 
on the dog, but even in it the differentiation is still very 
incomplete. 
“Tf we explore, for instance, the area for the wrist, we find 
that its limits are ill defined. In some parts of the area we 
obtain movements of the wrist only, but in other parts of the 
area stimulation produces not only movements of the wrist 
but also of the shoulder or of the digits or of the neck; and 
