THE MITOCHONDRIA AND OTHER STRUCTURES. 1 05 



figures, as for instance those of the spermatid, shows a granule in 

 the same position as that of the neutral red granule in our prepara- 

 tions, and, although the granule is stained like the mitochondria 

 with Benda's stain, Duesberg states that it is in all probability 

 not mitochondria. In preparations stained with Janus green 

 this granule remains unstained. The somatic cells, which form 

 the wall of the follicle and also the apical cell (Figs. I and 2), 

 are full of these bright red granules when the preparation is 

 stained with neutral red, but the germ cells contain only a very 

 few neutral red granules. 



With Janus green stain however, the germ cells are shown to 

 contain abundant mitochondria in the form of granular threads 

 or of small rod shaped granules. After the preparation has been 

 stained for a short time the granules coalesce into larger globules 

 (Figs. 4 and 5) and finally they disappear in the cytoplasm. 

 Long, thread-like mitochondria rapidly break into granules when 

 stained with Janus green (Figs. 13-20). 



Neither of the above stains showed the spindle threads during 

 mitosis. There was no appearance seen at any time during ob- 

 servation upon either the unstained cell or the cell stained by 

 means of the above vital stains, which could lead one to conclude 

 that the mitochondria are formed from any material at the ex- 

 pense of the nucleus as Wassilieff ('07) and his followers contend. 



Nucleus. -The various changes which the nucleus undergoes 

 during the so-called resting stage and during division can be 

 clearly observed throughout the development of the germ cells 

 from spermatogonia to spermatozoa. In the resting nucleus of 

 any stage chromatin threads were observed. In the nucleus 

 of the spermatogonium these chromatin threads or spiremes seem 

 to fill the nuclear space like so many sacs (Fig. i). When the 

 preparation was stained with neutral red, the walls of these 

 sacs became faintly pink and so revealed the boundaries of the 

 chromosomes. During the telophase, and in a few cases, in the 

 late anaphase of the spermatogonium, the spermatocyte and 

 the spermatid, the chromosomes have a granular structure 

 (Figs. 4, 10, 20). These granules appear to be uniform in size 

 and it might prove possible to count the number of granules which 

 compose a given chromosome. The importance of these granules 

 in "crossing over" phenomena may appear later. 



