A COMPARATIVE STUDY OF THE THREE PRINCIPAL 

 REGIONS OF THE SPINAL CORD IN A SERIES 



OF MAMMALS 



PEARL BRIGGS BULLARD 

 From the Laboratory of Anatomy, Tulane University of Louisiana 



TWENTY-FIVE FIGURES 



This paper presents some observations based on the study 

 of transverse sections of the three principal regions (intumes- 

 centia cervicahs, intumescentia himbahs, and middle of pars 

 thoracalis) of the spinal cord in a series of twenty-four mammals. 

 An outline drawing of a transverse section of the cords in each 

 region is included together with tables of measurements showing 

 variations in dimension and structure of the cords in the differ- 

 ent mammals. 



MATERIAL AND METHODS 



In most cases one representative only of a species of mammal 

 was studied. Hence all error due to individual variation is 

 included in this work. An average taken from the study of a 

 large number of individuals of each species would obviously be 

 of greater value. In so far as was possible to ascertain, all ani- 

 mals used were normal. A few of the specimens were kindly 

 furnished by Professor Hardesty with the sections ready for 

 study. The method by which they had been prepared, and which 

 was used for the remaining specimens of the list is, very briefly, 

 as follows. 



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