INFLAMMATION. 409 



municated the sensation of a large cavity underneath, filled with liquid, 

 and approaching to within two or three lines of the surface. There was no 

 adhesion or exudation at that point ; and the surface of the brain appeared 

 entirely normal, except slight cloudiness of the pia mater at the base of the 

 brain, a little posterior to the optic commissure. The incised surface of the 

 brain, at a distance from the abscess, showed no increase of vascularity. The 

 right hemisphere appeared in every way normal, except that its lateral ventri- 

 cle was filled with pus, but not distended. 



"On the left side, occupying the center of the hemisphere, was an abscess 

 as large as the fist of a child of two years, extending from within two to three 

 lines of the vertex, where its site corresponded with the yellow spot on the 

 surface of the brain, to the roof of the lateral ventricle. Through this roof 

 the abscess had burst, filling and distending the ventricle with pus, and thence 

 making its way into the lateral ventricle of the right hemisphere. The whole 

 amount of pus contained in the abscess and the two ventricles was perhaps 

 two ounces. 



" The walls of the left lateral ventricles were much softened, the upper 

 part of the corpus striatum and thalamus opticus being nearly diffluent. 

 The walls of the right lateral ventricle were slightly softened, but to a less 

 depth. The parietes of the abscess, which extended from the roof of the 

 ventricle to the vertex, as already stated, were indurated to the depth of one 

 and a half lines, except at the base of the abscess, which corresponded with 

 the roof of the ventricle, where softening had occurred. The spinal cord, so 

 far as it could be examined from the cranial cavity, had the usual vascularity, 

 but was slightly softened. 



" The cause of the encephalitis from which the abscess resulted was 

 obscure. The inflammation, so far as could be ascertained, was idiopathic. 

 There was no history of otitis, which is one of the most frequent causes of 

 cerebral abscess ; nor of heart disease so as to produce embolism. It seems 

 probable, since there was no fever till about the fourth day after the convul- 

 sions, that an abscess had primarily occurred in the hemisphere between the 

 roof of the ventricle and the vertex possibly some weeks previously. The 

 bursting of this into the lateral ventricle, and the constitutional disturbance, 

 inflammation, and softening to which these would inevitably give rise, affords 

 sufficient explanation of the history of the case, after the commencement of 

 the convulsions." 



* The specimen was kept in a very dilute solution of chromic acid for several 

 months, after which time it was hardened in alcohol and imbedded in a mix- 

 ture of paraffine and wax, whereby care was taken to enclose mainly the wall 

 of the abscess and its immediate surroundings. Previous to the beginning 

 of my studies, a certain number of sections had been made of the wall of 

 the abscess itself, as well as from other parts of the brain, such as the cere- 

 brum, the cerebellum, the medulla oblongata, and the gray matter. These 

 sections everywhere had been found holding a large number of so-called amy- 

 laceous corpuscles, exhibiting all the characteristic chemical and morpholog- 

 ical features of these formations. No other changes could be traced out, 

 nor did the blood-vessels show any anomalous conditions, excepting the capil- 

 laries, which were found dilated and choked with blood-corpuscles within the 

 inflammatory focus, as well as in its neighborhood. 



I made a number of sections, both from the wall of the abscess and the 

 surrounding portion of the brain, which sections embraced the gray matter of 



