Ranson, Alterations in Spinal Ganglion Cells. 145 



were \evy well suited. At the end of two months so mucli atrophy 

 has occurred that the relations given in Table II can no longer be 

 made out. 



These observations bear out the conclusion reached in a previous 

 paragraph that the reaction in the small cells is not secondary to 

 that in the large. If it were, it would be difficult to see why the 

 large ones should survive and the small ones disintegrate. These 

 small cells which do not have medullated axons in the nerve are 

 the first to react, show a typical axoual reaction, resulting in very 

 extensive cell destruction. These facts are very important for a 

 proper understanding of the architecture of the spinal ganglion, but 

 their bearing on that subject can best be discussed in another place. 



Tlie Phase of Be pair. We come now to the study of the reparative 

 processes by which the surviving ganglion cells regain their normal 

 appearance. For this study the preparations -from the young rats 

 proved especially fitted. Because of the rapidity with which the 

 ganglia passed through the various phases, the repair came very 

 much earlier in these specimens than in any previously described. 

 Repair began on the eighth or ninth day and was almost complete 

 in 20 days. During this interval specimens were taken every two 

 or three days and a complete series representing the reparative 

 changes was thus obtained. In the preparations of other investi- 

 gators taken from the ganglia of other, and older, animals the 

 repair occurred late when the specimens of the series were taken weeks 

 apart. 



Nine days after the operation the nuclei of the large cells begin 

 to recede from their peripheral position and come more and more 

 in the course of the next few days to occupy the center of the cells. 

 There is little change as yet in the character of the chromatic 

 granules. In most of the cells the stainable substance forms only 

 a narrow ring about the periphery of the cell ; the remainder of 

 the cytoplasm stains a difi^use light blue. Twelve days after the 

 operation only a few of the large cells show peripheral nuclei 

 and there is a very noticeable augmentation in the quantity of 

 the tigroid masses. As this accumulates in the cell it disposes 

 itself in two ways. A part of it goes to increase the breadth and 



