21 ( 



presence ol' j)ignu'iil rods and "granules all the lime in llui 

 culUirc medium. 



Smith ohscrvcd llial Ihc |)i<,nnent rods, lakcn up by 

 Hie ril)r()l)lasts. appeared [o swell up and Ihere was an ac- 

 tual decrease in colour. Such decolourizalion did not take 

 place in the granules of the j)i<)inent e|)itheliiim. The pig- 

 ment granules look up the neutral nnl in the cultures and 

 the slain remained there even alter I'ixaliou in Zenker s 

 fluid. 



Smith found that if he stained the cells with the com- 

 bination stain of neutral red and Janus green the mito- 

 chondria stained bright blue with Janus green and the pig- 

 ment granules took uj) the red. This differential slain between 

 mitochondria and the degeneration granules and pigment 

 has been use<l also by Cow dry i'^) and Lewis and 

 Lewis'*''^). Smith did not find that the pigment gra- 

 nules were extruded from the nucleus. There was no evi- 

 dence that the mitochondria changed into pigment. The 

 pigment granules arise and develop in the cytoplasm of the 

 cell. Small colourless granules were seen in the cytoplasm 

 of the cells, cultivated 12 hours; these granules increased in 

 size, number and colour until the}^ became rod-shaped and 

 black of coh)ur. The formation could be distinguished in. 

 two stages: a) the formation of a coloui'less chromogen 

 and b) the production of colour in the chromogen. 



Matsumoto ^o^) investigated the granules, vacuoles and 

 mitochondria in the sympathetic nerve fibres. He found 

 that there was not a regular distribution of the mitochondria 

 in the fibres or nerve end. The finding of this would 

 of course be expected if the mitochondria gave rise to the 

 neurofibrillse, such as has been claimed by several inves- 

 tigators. 



The structure of certain male germ cells has been studied 

 by Chambers 116) (i o 1 d sc h m i d t 223) and M. R. L e- 



W i S 359). 



