137 



of determining what parts had suffered by the external study. Sections 

 in celloidin were made and stained by the Weigert method. The 

 results are best indicated by comparing the changes as indicated in 

 the photographs 1 and 2. The proportion of the white to the grey 

 in photo I is as one would expect in the normal Amphibian. The 

 grey substance sends numerous strands out into the surrounding white 

 layer, the nuclei are numerous and rather evenly scattered. The 

 nuclei around the neurocoele are elongated and prominent. 



Fig. 1. 



Fig. 2. 



Fig. 1. Cross section of spinal cord through the dorsal region of animal starved 

 for 4 months. Note the well defined cells of the gray substance. 



Fig. 2. Cross section of spinal cord Jhroiigh corresponding region of animal 

 starved for 16 months. The amount of the gray substance is greatly reduced. Note 

 the change in form of the cross section due to the reduction of gray substance. 

 Figures 1 and 2 are shown at the same magnification. 



In the 16 months starved animal, the changes are striking and 

 not a as anticipated. Proportionally the ratio of white and grey has 

 undergone a marked change. Comparing the relative thickness of the 

 white layer in the two photographs, it is seen that there is not much 

 difference in appearance except that the longer starved specimen seems 

 more compact. It must be apparent that the conspicuous reduction in 

 size is not due to marked changes in the white layer. While staining 

 the 16 months starved sections we thought that as we made an ex- 

 amination to determine how the stain was differentiating that the center 

 had dropped out of these sections, so transparent was this region. 

 After clearing and mounting the real conditions were revealed. The 

 grey area had shrunken involving both some of the nuclei and the 



