118 PRACTICAL HISTOLOGY [XV 



4. Transverse section of a sympathetic ganglion 

 from the sympathetic chain. (Osmic acid; paraffin.) 

 Under both low and high power compare this section 

 with that of the spinal ganglion in 1. Note 



The nerve cells vary in size, but on the whole are 

 not so large as in the spinal ganglion ; they are more 

 irregular in shape, and a considerable number of non- 

 medullated fibres lie between them. 



The great majority of the medullated fibres are 

 small (2/4 to 3//,). 



5. Transverse section of lumbar spinal cord of 

 ox, calf, or dog. (Potassium bichromate ; cut frozen , 

 picrocarmine two or more days.) 



Note the large multipolar nerve cells of the 

 anterior cornu; the processes are given off in all 

 directions, some are cut short, others will be seen to 

 divide in the section into finer and finer branches 

 (protoplasmic processes or dendrons) ; here and there 

 a cell may be seen from which a rather large process is 

 given off which runs outwards through the white 

 substance without branching (axis cylinder process or 

 axon). 



6. Take a little of the anterior cornu of the spinal cord from 

 a recently killed animal, spread it out on a cover-slip and make 

 a dry film. (The film may be fixed by heating in the manner 

 given for blood Less. in. 4 ; this is not necessary, but it helps 

 to prevent diffuse staining.) Stain as in 3 a. 



Observe (h. p.) the isolated nerve cells with their branches 

 and basophil clumps and granules. Where the axon leaves the 

 cell, there is usually a cone of cell substance without basophil 

 material. 



