4 MAHY JANE HOGUE 



The disappearance of the neutral red from the amoeba seems 

 to be due to oxidation. One small amoeba was watched for five 

 hours. At 9:00 in the morning it contained fifteen neutral-red 

 granules. The color gradually faded from these granules until 

 by 11 : 30 only one granule had the neutral-red color and by 12:00 

 this color had disappeared. The granules themselves did not 

 dissolve, but could be still seen in the amoebae. Unfortunately, 

 janus black no. 2 had been also used, and this eventually kills 

 the cells. However, at 4:30, this particular amoeba was still 



Fig. 1 Amoeba showing neutral-red granules of different sizes and neutral- 

 red vacuoles containing one or two neutral-red granules. 12.5 ocular, 1.9 oil 

 immersion. 



very active with numerous stained mitochondria, but the next 

 morning it was dead. 



The neutral-red granules and vacuoles were of varying size 

 and number. Some amoebae had many small granules and many 

 large vacuoles, which contained from one to two granules (fig. 1). 

 In the fibroblasts one frequently finds neutral-red channels, but 

 they have never been observed in the amoebae. 



Brilliant cresyl blue 2 h 



The amoebae were much more sensitive to this stain than were 

 the tissue-culture cells. One drop of a weak solution was added 



