72 Journal of Comparative Neurology. 



main. The precommissure, the olfactory fibres of which should 

 be visible at this point, has completely disappeared. 



Notice that the inner capsule, even in the first section, con- 

 tains quite a number of medullated fibres. These, there- 

 fore, must have their origin not in cells of the cortex but in 

 structures lying farther caudad. The next section shows that 

 the caudatus is relatively well preserved on the right side while 

 on the left only insignicant fragments remain. A trace of the 

 cortex belonging to the trigonum olfactorium lies ventrad of the 

 head of the striatum on the brain base. The lentiformis is al- 

 most completely removed with the hemispheres. Farther caudad, 

 in region of the commissura media, the thalamus is present on 

 both sides but all its niduli are atrophied to a marked extent. 

 Only a much atrophied internal capsule, not a trace of hemis- 

 pheres, no fornix and only the fragments of an ammonshorn of 

 one side remained. The uncus of the parietal lobe is retained 

 because the operator wished to pseserve the optic nerve. In 

 this he was successful on the right side but on the left side the 

 section passed a little too far mesad and also removed the corpus 

 geniculatum laterale. Thus the optic nerve of that side is atro- 

 phied although intact on the other side. Behind the sections 

 here figured all the thalamus ganglia are present and send their 

 fibres caudad quite like those of a normal brain. In spite of the 

 enormous injury in the forebrain region, the tegmental region and 

 mesencephalon gradually appear, sections passing through 

 which are but slightly distinguishable from those of a normal 

 midbrain. The farther caudad one goes the fewer tracts are af- 

 fected till, as already remarked, in the cord the only defect is the 

 absence of the pyramidal tracts. 



I have thus far scarcely taken into consideration tracts sec- 

 onarily degenerated, in part because these relations lie outside the 

 range of this lecture, and in part because the investigation is as 

 yet incomplete. Our present purpose is to indicate the ex- 

 tent of the destruction due to the operation. 



I again summarize the results. Of the entire cerebrum, 

 aside from the remnants of the right Ammonshorn, there remains 

 not a trace except a strongly atrophied uncus of the parietal 



