The vital staining of mitochondria with janus green etc. 277 



The morphology of the mitochondria is variable (fig. 3). Granular 

 forms predominate. The granules tend to be arranged in rows. 

 Straight and curved, rods and filaments occur in varying num- 

 bers. Sometimes the rods are dumb-bell shaped and the filaments 

 beaded. 



The distribution of mitochondria is characteristic. They are 

 more numerous on the side of the nucleus where the cytoplasm is 

 most abundant. Occasionally they are restricted to this region forming 

 a brilliant, highly colored clump, which is very conspicuous in well 

 stained preparations (fig. 3 a). Sometimes, however, when the nucleus 

 is excentric, they extend into the thin layer of cytoplasm which 

 surrounds it (fig. 3 b). There is no indication of a radial arrangement 

 The amount of mitochondria in each cell seems to be fairly constant. 

 In the best preparations with good light and apochromatic lenses they 

 may be counted with difficulty. The number ranges from about 

 twenty to forty-five, the average being about thirty-two. They are 

 abundant in the cell shown in fig. 3 b, rare in that illustrated in 

 fig. 3 c. I have been able to count them with ease in smears of the 

 lymph gland of the guinea pig. 



No traces of a centrosome, granules of segregation, or of the so- 

 called azurophile granules could be seen. 



These observations were also confirmed by the study of fixed and 

 stained smears. 



4. Large lympiiocytes (fig. 4 a and b). 



Synonyms: large mononuclear leucocytes and transitional leucocytes. 



The mitochondria may here also be seen in the living cells, in 

 native plasma, without the use of any dye or salt solution. 



The large lymphocytes stand next in order to the true lympho- 

 cytes in their permeability to janus green. The mitochondria in them 

 may be observed to take up the dye just as those in the lymphocyte 

 do. It is not necessary to repeat the sequence of changes in the 

 reaction for it is the same as in the lymphocyte. 



Diethylsafranin also stains the mitochondria specifically. 



The shape of mitochondria in the large lymphocytes differs in no 

 wise from that of those in the smaller ones. 



