226 W. SCHOLZ, W. SCHLOTE AND W. HIRSCHBERGER 



Fig. 19. Detail of Fig. 18. The large nerve cells are of normal shape; their peri- 

 karyon is lightly stained, and the nucleus is not strikingly altered. The nuclei of the 

 smaller nerve cells contain rather coarse chromatin particles. 



known, but the experiments of Scharrer (1933) and of Cammermeyer 

 (1960) suggest that they can be produced artificially by simple mechanical 

 pressure on the cortex. A high degree of swelling and vacuolization of the 

 cytoplasin with loss of ribonucleic acids and the occurrence of coarse 

 chromatin particles within a nonpyknotic nucleus seem to constitute evidence 

 of necrosis. But again, the nerve cell nuclei of rodents may normally have 

 rather coarse chromatin particles. The third variety of nerve cell alteration 

 referred to by these authors seems to resemble the so-called ischemic type 

 of nerve cell change. Certainly, as soon as a breakdown of the nucleus is 

 established, death of the cell must be accepted if postmortal processes can 

 be excluded. We have observed the cytoplasm of such cells to be acidophilic, 

 staining with eosin and even with azocarmine and acid fuchsin, but we 

 have had no opportunity to make coinparisons with the results obtained 

 by Schiimmelfeder (1957) with acridine-orange. 



Krogh and Bergeder (1957) did not state whether the pyknosis of the 

 granular cells is due to a direct influence of irradiation, or if edema of the 

 granular layer may play an intermediary role. Schiimmelfeder ( 1957) favors 

 a direct influence of ionizing rays. However, it is not easily imderstood why 

 the same cause in the same quantity elicits a shrinking one time and a high 



