178 PATHOLOGY OF TYPHUS IN MAN 



plot the relative frequency of the lesions in different .cortical 

 areas, and the only positive conclusion upon this subject that 

 we have made is that the parietal lobe leads in abundance of 

 lesions and the occipital lobe shows fewest. 



The medulla and pons probably show the most numerous 

 lesions. We agree with Ceelen and Nicol that sections through 

 the medulla including the olivary bodies offer the best chance 

 of discovering these lesions; they are particularly numerous 

 in the olivary nuclei. We have counted fifty-two lesions in a 

 single section through the medulla at this level. The pons 

 comes next in our estimation; the lesions are most abundant 

 in the gray matter (nuclei pontis) and central gray matter, as 

 elsewhere in the brain. The mid-brain and basal ganglia in our 

 estimation come third as seats of predilection for these lesions, 

 then follow the cerebral cortex, Ammon's horn, and cerebellum. 

 The proliferative lesions are found in the white matter, but 

 much less frequently than in the gray. In the cerebrum it is 

 difficult to find them in the white matter while in the medulla 

 and pons they occur with frequency in the fiber tracts. In one 

 case only was a proliferative lesion found in the internal 

 capsule (case 20). In the cerebral cortex the lesions occur in 

 all layers; but they are most numerous in the middle group of 

 ganglion cell layers, second to fifth. In the basal ganglia, the 

 thalamus, caudate nucleus, and lenticular nucleus are equally 

 susceptible. In the cerebellum, the molecular layer and the 

 dentate nucleus are most often the site of lesions; next in 

 order come the Purkinje cell layer, the granular layer, and 

 white matter. In the medulla, the olivary nuclei are most heav- 

 ily affected. Lesions in the central gray matter of the fourth 

 ventricle just below the ependyma are common. At the level 

 of the decussation of the pyramidal tracts lesions are always 

 numerous. 



The occurrence of capillary hemorrhages usually restricted 

 to the perivascular space is shown in Table XVI, and are prob- 

 ably of importance in the production of cardiac and respiratory 

 symptoms. 



The choroid plexus from each of the thirty-seven brains was 



