Anatomy". — "(M thf. tmrlabilitii of the number of giant pyramidal 

 cells in the Heschl convolution in man". By J. P. Ver- 

 GOUWEN Jr. (Communicaled by Prof. J. Boeke). 



(Communicated in the meeting of May 26, 1917). 



Some years ago Dr. A. B. Droogleevek Fortuyn observed that in 

 a case of non-congenital deaf-inntism the cortex of the Hf.schl 

 convolnlion (Area [41 -|- 42] after Brodmann) in some places con- 

 tained very few giant pyramidal cells and in other places none at 

 all. However, he found the same circumstance in 'a case where 

 there was no deaf-mutisin. (Archives of Neurology, Vol. 5, 1911). 



In order to be able to form a judgment on the variability of the 

 number of giant pyramidal cells in that part of the human cerebral 

 cortex, the following investigation was undertaken, extending over 

 10 normal cases and 5 deaf and dumb. 



The portions of the normal cerebral cortex of the Heschl convo- 

 lution, embedded in paraffin, were cut in sections of 10 fj, and of 

 evei-y fifty sections one was taken out and. stained for examination 

 with cresyl-violet. The cerebral portions of the deaf and dumb were 

 stained with methylene-blue, and again one out of every fifty 

 sections was examined. 



Among the normal cortical portions 8 were left and 2 right, of 

 the deaf and dumb 4 were left and 1 right. 



In all the obtained sections the number of giant pyramidal cells 

 was determined. The following figures show how this number 

 varied in the counted sections. 



(The number of figures in each series indicates the number of 



sections examined in that case). 



7.4.1.3.1.3.5.3.2.3.4.4.6.2.2.3.8.4.5.2.3.2. ') 



2.3.1.1.2.1.1.2.2.3.1.2.2.2.4.5. 



3.2.2.0.1.1.0.3.3.2.2.1.3.2.2.4.3.3.0. 



5.6.2.5.3.6.5.4.3.4.4.4.3.2.4.2.2.3.2.2.1. 



3.2.2.2.1.0.0.2.1.1.3.4.0.2.1.1.2.0.0. 



0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0. 



1.4.1.3.2.1.2.2.2.2.1.3.1.1.4.1.2.2.3.3. 



1,3.1.0.1.2.0.2.0.0.1.0.2.0.0.1.2.2.0. 



0.2.0.1.2.3.1.4.2.1.3.1.1.4.1.1.1.2.0.0. 



1.2.2.0.1.1.0.0.1.1.1.0.1.0.1.0.2.2.2.0. 



1) n = normal, d = deaf and dumb, r = right, 1 = left. 



