310 ALWIN M. PAPPENHEIMER 



may be present in cells which show active amoeboid motion, and 

 appear otherwise healthy, there is no reason for considering the 

 change a degenerative one, but rather, in accordance with modern 

 ideas, as an evidence of sub-oxidation. 



In the description of the fixed material, it was stated that 

 granulae could be demonstrated with reasonable certainty in the 

 small thymus cells. The following 'vital' stains, applied by 

 adding dilute solutions in Ringer's fluid to the cultures, showed 

 the presence of granulae; neutral red, trypan-blau, and Janus 

 green. With trypan-roth, isamin-blau, and new methylene blue 

 GG, the refractivity of the protoplasm is so changed that the 

 minutest fat droplets appear with great distinctness, but there 

 is no actual staining of the granules. By adding neutral red to 

 the culture, some but not all of the cells will be found to contain 

 a few granules. It was not however, possible to demonstrate 

 granulae in the small cells by injecting strong solutions into the 

 dorsal lymph-sac, and after general diffusion of the dye had 

 taken place, teasing the thymus in Ringer's solution. Red 

 stained granules and larger masses of colored material are found 

 in other cells, particularly the myoid cells by this method, as 

 well as when added directly to the plasma. 



With trypan blau, fine discrete granulae are found in many of 

 the small cells. These are sharply localized to one segment of 

 the cell, forming a dark bluish disc or cap which is very striking 

 when seen with the low power. After a time, the nucleus gradu- 

 ally takes a faint bluish tinge. 



With Janus green, extremely distinct granulae appear in some 

 but not all* of the cells of the small type. The dark greenish 

 color of the granulae develops slowly, reaching its maximum 

 intensity after about ten minutes. They are seen as sharply 

 circumscribed dots, which vary from barely visible points up to 

 the size of a large coccus. They are grouped at one pole of the 

 cell facing the indentation of the nucleus and show no recogniza- 

 ble radial or linear alignment. They appear to be more numerous 

 and attain a larger size than the granulae seen in Benda prep- 

 arations, but they correspond closely to these as regards their 

 location in the thicker portion of protoplasm facing the depres- 

 sion of the nucleus. 



