208 



ber ol" siiiiiU granular rings. Al [Uv lime oT mitosis, about, one- 

 hall" llif (iuanlil> ol niilochondria is scparalecl inlo each 

 (laughler cell by the plane of division. The mitochondria are 

 exlremeh [)lastic bodies and react moi'e rapidly than any 

 oilier cell siruelure. Their shape is easily inl'luenced !)>• heal. 

 carl)on dioxide, acids, alkalies, lal solvents and ix^lassium 

 permanganate, or by changes in the osmotic pi'essui'e ol' tlie 

 surrounding medium. The mitochondria are stained in Ihe 

 living ceils by Janus green, but not by -Nile blue B extra 

 or brilliant crcsyl blue 2 b except in the dead cell. There 

 was no evidence of a direct relation between the mito- 

 chondri'i and the formation of either the fat drojilets or 

 the vacuoles. 



The generation granules and vacuoles do not arise from 

 the mitochondria 0\. H. L e wis) aco a) gy j^e combination 

 stain of neutral red and Janus black Xr. 2, the degeneration 

 granules are stained bright red and the mitochondria blue- 

 black. Clertain fixatives, especially those containing acetic 

 acids, destroy the mitochondria leaving the granules un- 

 affecleil. Also Prigosen^^-) was able to distinguish l)e- 

 tween degeneration granules and mitochondria. 



The pigment formation was studied in vitro by T. S m i I h 

 *^-). He found that there was no connection between mito- 

 chondria and the pigment formation. He studied the pig- 

 ment in the retinal epithelium of the chickens eye and 

 found that the pigment granules were usually plump rods, 

 the length varying from one and a half to five times theii' 

 width. The colour was mostly dark brown or black. Light 

 and heat had a marked influence on the movement of the 

 pigment, in form of acceleration. They moved with a swift 

 and jerky motion. Smith observed also the pigment granu- 

 les or rods in the culture fluid, — a thing which I can 

 only confii-m. I observed these long ago in the embryonic 

 tissue juice, and thought at first that they were bacilli, — 

 further examination jjroved however to me, that they were 

 the pigment rods from the retina. They had precisely the 



