NUCLEAR CHANGES IN RANA CLAMITANS. 1 35 



diesem Saum von einander trennen, dann aber tritt eine bedeu- 

 tende Wucherung von Kernen auf, und zwar scheint dieselbe 

 auszugehen von den sogenannten Kornern,i deren Inhalt vollig 

 homogen und stark lichtbrechend erscheint. Durch Picrocarmin 

 werden diese Elemente ebenfalls stark tingirt, und nun sieht 

 man an diesen nahezu gleich grossen Kornern Kerntheilungen, 

 ohne dass jemals eine Spur von karyokinetischen Figuren con- 

 statirt werden konnte, in der Weise auftreten, das der Kern oder 

 die Korner sich in der bekannten Weise schuhsohlenformig 

 einschniiren, und dass dann aus beiden Halften Elemente gleicher 

 Art hervorgehen. Nicht nur eine einmalige Einschniirung glaube 

 ich beobachten zu konnen, sondern auch eine mehrfache, so dass 

 der Kern sich bei diesem Process nicht nur in zwei, sondern auch 

 in mehrere Stiicke theilen kann." 



Fraisse discusses further the evidence that the nuclei from the 

 end of the spinal cord, which are found in the lymph-like border, 

 divide amitotically. This agrees with the present observations. 

 But he is satisfied to show that direct division does take place. 

 So far as my preparations show, there are few evidences that the 

 nuclei which divide amitotically afterward become normal nuclei. 

 In some of the preparations of stages at which the deeply-staining 

 nuclei have almost disappeared, there are a few nuclei which stain 

 only slightly darker than the normal ones, and at this time there 

 are no stages between these and the fragments. These few 

 slightly darkened nuclei may, then, be forming normal nuclei 

 again. All other evidence points towards the conclusion that 

 at successive stages, these deeply-staining nuclei become smaller 

 and smaller as if fragmentation or repeated direct division, is 

 taking place. The conclusion from these facts is that nuclei 

 which have only started to degenerate may perhaps return to 

 the normal condition, but that nuclei that have gone so far as to 

 divide amitotically are destined to fragment. 



2. The Appearance of Leucocytes. 



Barfurth (1891), working on the regenerating spinal cord of 

 the frog larva at forty-six hours and at three days, makes the 



1 Kornern-nuclei of the gray substance, which are not present in the distal region 

 of the spinal cord. 



