128 TEIJI HOSHINO 



here are small in caliber, yet the difference between the affected 

 and normal is well defined. The lateral area of the funiculus has 

 a slightly larger caliber cf fibers than the median pcrtion, but 

 even so they are smaller than those in the normal. In the upper 

 enlargement, the medial triangular area in this funiculus along 

 the median sulcus stains a deep blue to black in the normal, 

 while in the affected one it shows a paler color and reduced 

 breadth. The measurements of fibers are given in table 3. In 

 the lower enlargement, the funiculi posteriores are not attached 

 to each other, but they are separated by a wide space, the sinus 

 rhomboidalis ; the sinus side of each funiculus is convex, while 

 the other side is closely applied to the dorsal horn. The funiculi 

 in the affected specimens are not reduced ventrodorsally, but do 

 show a diminution transversely. There appear to be two kinds 

 of fibers in the funiculus in the normal pigeon. One occupies 

 the medial fourth and measures 3.1 n on the average, while the 

 other group occupies the lateral three-fourths and has fibers of 

 much larger caliber, 5.1 /*. In these two areas of fiber groups, in 

 the affected specimens, the fibers have a smaller caliber and thin- 

 ner myelin sheaths ; the average caliber of the fibers in the medial 

 portion is 2.2 n, while those in lateral portion measure 4.2 fx. 

 Moreover, the arrangement of the fibers is looser. 



No segmentation or decoloration in the myelin sheaths of the 

 nerve fibers is seen. 



Gray matter. The gray matter of the spinal cord of the af- 

 fected birds shows a reduction in both the anterior and posterior 

 horns and in the central gray matter. Both horns are reduced 

 especially in width, as shown in the tables (3 and 4), but there is 

 not much reduction in length. There is, then, only a decided 

 meagerness of both horns. Besides these changes, other condi- 

 tions may be pointed out. 



In the anterolateral portion of the ventral horn, the ganglion 

 cells are only half the normal in number and the large cells present 

 in the upper and lower enlargements are decidedly reduced in 

 size (table 3), and usually have a slender shape, but are seldom 

 shrunken. In both enlargements, a small area of ganglion cells 

 at the medio-anterior portion of the ventral horn protrudes into 



