74 PEARL BRIGGS BULLARD 



Most of the spinal cords were removed entire from the verte- 

 bral columns as soon after the death of the animal as possible 

 and placed in a 10 per cent solution of formalin. After fixation 

 a segment through each of the enlargements (cervical and lumbar) 

 and the smallest portion of the thoracic region was cut from the 

 cord. The blocks which were taken from the sixth cervical, 

 the eighth thoracic, and the third lumbar segments were mor- 

 danted five to ten days in JMuller's fluid, embedded in celloidin, 

 and sections cut at 30 micra. The sections were stained by Pal's 

 modification of the Weigert method for medullated nerve fibers. 



Drawings. The figures were made in outline by means of the 

 Edinger projection apparatus set for a magnification of eight 

 diameters. They are not intended to present detail of structure 

 but are of value in comparing the form of the several components 

 of the different cords. What little detail is given, however, was 

 obtained with the compound microscope (Leitz, Objective 2, 

 Ocular 3). In the case of the lumbar regions of the ox and of 

 the horse, one side of the largest segment of which was slightly 

 injured in removing the cord, bilateral symmetry was assumed 

 and the injured side was reconstructed from the intact half. 

 With the exception of the lumbar region of the elephant which 

 I was unable to obtain, the three drawings from the cord of each 

 animal in the series is complete. 



Tables. Data obtained for use in making the numerous gen- 

 eral comparisons of the structures of the spinal cord is accumu- 

 lated in the following tables with the animals arranged according 

 to body weight. Table 1 gives a complete list of the animals 

 with body weights. The underscored figures are true body 

 weights of the animals, the others approximate. Tables 2, 3, 

 and 4 record for each region certain measurements taken accord- 

 ing to the scheme shown in text figure A the lines in which indicate 

 the extent and direction of each measurement. The numbers 

 of the lines in this figure correspond to like numbers in the tables. 

 In all cases measurements of each half of the cord were taken 

 and the average recorded after dividing by eight, the magnifica- 

 tion represented by the drawings. Table 5 is constructed from 



