PLATE 5 



EXPLANATION OF FIGURES 



23 Similar view to figure 22 through the trigeminal nerves (ex. 64), but a little 

 more peripheral. Observe that the various nerves are further separated and 

 that the degenerated descending mesencephalic root fibers are confined to the 

 motor components of the nervus masticatorius, namely, the masseter, pterygoid, 

 and deep temporal branches. X 8. 



24 From the same section as figure 23, but showing the mandibular, auricu- 

 lotemporal, and masticator nerves, together with a strand from the ophthalmic 

 and maxillary nerves (a and b) more highly magnified so that almost every 

 particle of degenerated myelin could be accurately drawn. This figure clearly 

 shows that there are no more degenerated fibers in the auriculotemporal, man- 

 dibular, and buccal portions of the masticator than there would be in a section 

 of any normal nerve. Also that the degenerated descending mesencephalic root 

 fibers are confined to the masseter, pterygoid, and deep temporal portions of the 

 nervus masticatorius. X 32. 



25. Transverse section of the trigeminal nerves from the same series as 

 figure 23 (ex. 64), but more peripheral. The nervus ophthalmicus does not 

 appear in this section and the other nerves have become further separated. As 

 in the previous figures, the degenerated descending mesencephalic root fibers 

 are confined to the motor branches of the N. masticatorius, namely, the masseter, 

 pterygoid, and deep temporal nerves. Observe the latter leaving the main 

 trunk to go to the temporal muscle. , This is the most distal of the two deep 

 temporal nerves; the first or most central was given off from the masticator 

 nerve shortly after it left the semilunar ganglion. X 8. 



26 As above (ex. 64), but from a more peripheral section. Like the previous 

 sections, the degenerated descending mesencephalic root fibers are confined to 

 the motor portion of the nervus masticatorius, but only two such nerves remain 

 in this trunk, the N. massetericus and N. pterygoideus. The N. temporalis 

 profundus has left this trunk to go to the temporal muscle, the N. buccinatorius, 

 a sensory branch containing no descending mesencephalic root fibers, appears 

 in this section a little lateral to the N. maxillaris. X 8. 



27 Shows the nervus masticatorius from the same section as figure 26 more 

 highly magnified so that every particle of degenerated myelin could be accurately 

 sketched. Observe the degenerated descending mesencephalic root fibers in the 

 masseter nerve and its branch, and in the pterygoid nerve. The pterygoid 

 nerve, which is not branched, is about the same size and exhibits about as 

 many degenerated fibers as it did more centrally in figure 24. On the other 

 hand, the masseter nerve has branched and the main trunk is smaller than it 

 was further centrad, but retains about the same proportion of degenerated to 

 normal fibers. X 32. 



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