IO8 MARGARET REED LEWIS AND WM. REES B. ROBERTSON. 



First Spermatocyte (Growth Period}. As the cell grows in size 

 the amount of mitochondria appears to increase correspondingly 

 and certainly the mitochondria of the spermatocyte stain much 

 more intensely with Janus green than do those of the spermato- 

 gonium. The neutral red granules are few in number and scat- 

 tered throughout the cytoplasm. 



In the later growth period the mitochondria become grouped 

 into two, or in a few cases, possibly more masses (Figs. 7 and 8 

 and n). Unfortunately the significance of this was not compre- 

 hended, but it is without doubt closely allied with some change 

 in the cell itself, as the massed arrangement of the mitochondria 

 is quite characteristic of the synapsis stages. There was no 

 evidence that the mitochondria granules paired during synapsis, 

 although the pairing of the chromosomes w r as clearly seen. 



First Spermatocyte Division. During the prophase and early 

 metaphase of the first spermatocyte, the mitochondria migrate 

 away from the two masses of mitochondria granules and elongate 

 towards the two poles of the spindle (Fig. 12), so that when the 

 chromosomes are arranged on the spindle plate, the mitochondria 

 appear as threads which more or less closely surround the 

 spindle. As the chromosomes move apart, the mitochondria 

 become drawn out into straight, even threads closely attached to 

 the spindle between the two groups of chromosomes (Figs. 13, 

 14 and 15). Since they are much longer and more refractive 

 at this stage, they may be easily mistaken for the spindle fibers 

 and some cytologists have stated that the mitochondria in the 

 germ cell are but the remains of the spindle fibers. A simple 

 experiment shows that this is not the case in Chorthippus curti- 

 pennis. Figs. 21, 22 and 23 were made from the living cells in 

 the cultures and then an opening was made in the vaseline ring, 

 which supported the cover slip and a drop of glacial acetic acid 

 was placed on the slide near to the opening so that the fumes from 

 the acid passed through the opening and acted upon the prepara- 

 tion. The mitochondria were destroyed at once and became lost 

 within the coagulum of the cytoplasm, and, where previously 

 no spindle could be seen, there now appears a typical spindle 

 (Figs. 24 and 25). Fig. 26 shows the remains of the spindle fibers 

 near the periphery of each daughter cell, but the mitochondria, 



