1888.] Dr A. Bruce on Absence of Corpus Callosum. 325 
the level of the optic thalamus (seen from below, to show the 
arched form of the structures spt. and r.h.). f fornix. 
Big. 10. Similar section slightly lower than the fig. 9 (from 
above). Letters as in preceding sections. Note, spt. as a broad 
strand of white fibres lying internal to the anterior horn of the 
ventricle (represented by a black line). Its fibres pass from below 
backwards and upwards, and enter r.h. (fig. 9). Note that in fig. 9 
r.b. is arched, and has the fornix along its inferior surface, o.r., 
optic radiation of Gratiolet; ^., a narrow strand (drawn exactly of 
natural size) internal to o.r., and representing the tapetum, which 
remains when the forceps major is removed (note absence of all 
callosal fibres). The disproportion in size between the structures 
marked t. and spt. is to be noted (see cases of Onufrowicz and 
Kaufmann). In fig. 10 the apparently normal relation of fimbria 
of fornix {f.x.), fascia dentata (/.d), and cornu ammonis (c. amm)is> 
to be noted. In the section from which fig. 9 was drawn, the mass 
of the fibres of r.h. passed into the white investment of the cornu 
ammonis. 
Apart from the absence of the great transverse commissure, the 
points of special interest in the above case are the deformity of the 
frontal lobe, the peculiar radiated arrangement of the convolutions 
on the median aspect of the hemisphere; the value of the structures 
spt. and r.h.', the relation of the callosal fibres to the internal 
capsule (with reference to Hamilton’s recently expressed views) ; 
and finally the light thrown on the ordinarily accepted opinions 
with regard to the functions of the corpus callosum. 
With a view to their elucidation, I have abstracted the accounts 
of all the recorded cases available to me. The most important 
papers are in the Arcliiv fiir Psychiatrie, vol. i. (Sander), vol. 
xviii. (Onufrowicz and Kaufmann), and in the Glasgoio Medical 
Journal, 1875 (Knox). It is much to be regretted that the ac- 
counts are in most cases extremely meagre, and evidently frequently 
inaccurate. 
1. Gerehrum Divided into Two Hemispheres, hut Corpus Callosum 
completely absent. 
I. Eeil, Arch. f. Physiologic, xi., 1812, p. 341, quoted by Sander, 
Arch. f. Psychiatrie, vol. i. p. 135. — Woman, aged 30 ; stupid, could 
