APPENDIX. 



COMPARISON OF THE AVERAGE SIZE OF THE NUCLEI IN THE 

 NERVE CELLS WHICH ARE RELATED TO MOTOR NERVES. 



IN an article which appeared in the Journal of Nervous and Mental 

 Disease, Jan., 1880,* I published the fact that the nuclei, in the large 

 nerve cells of the frog's crural enlargement, were larger than those in 

 the similarly placed cells of its brachial enlargement, giving, at the same 

 time, the measurements of these elements in micrometer divisions. 



The difference in average size was considerable ; and believing, then 

 as now, that exact measurements of nuclei are more satisfactory than un- 

 certain and widely varying dimensions of the irregularly shaped masses 

 of surrounding protoplasm, I was encouraged to extend my researches 

 to the nerve centres of many other animals, and to the nuclei in the sup- 

 posed cells of origin of the cranial motor nerves. 



Prior to this time no similar observation had been made. Both 

 Reissner and Stieda the former, treating of the central nervous system 

 of the frog, and the latter, of the spinal cord of the turtle publish, in 

 millimeters, diameters of nuclei in the nerve cells, but without compar- 

 ing the average size either of the cells or of their nuclei in the two en- 

 largements of the cord, or in the ganglia of the encephalon. 



No attempt has been made by either one of these writers to con- 

 nect the dimensions of these elements with differences in motor energy 

 developed in the related muscles. 



* See the same journal for July, 1880, Jan., iSSi & Jan., 1882. 



