390 MARGARET R. LEWIS AND WARREN H. LEWIS 



sion and to compare the results. The cell shown in figure 26 a 

 was first studied and drawn while living. The clear, refractive 

 fat globules were easily recognized. A drop of nile blue B extra 

 (1-100,000) was added without any change in the appearance of 

 either the fat globules or of the mitochondria. After a few 

 minutes this was washed off and the preparation was fixed in 

 osmic acid vapor for a few minutes. The same cell was then 

 examined and the fat globules were stained a yellow brown, 

 while the mitochondria remained clear. A drop of nile blue 

 B extra was then added. The fat globules took a dark blue 

 stain and the mitochondria a pale blue. A drop of Sudan III 

 was then added and the fat became yellow while the mitochondria 

 stained a trace of blue. The specimen was then dehydrated 

 and stained with Bensley's anilin fuchsin, methylene green. The 

 fat droplets were dissolved and the mitochondria stained a bril- 

 liant red. 



Early in the experimental work it was observed that the mito- 

 chondria under certain conditions became granules around a 

 vesicle. This vesicle stained pink with the nile blue B extra in 

 the living cell, and at that time it was supposed that this indi- 

 cated the formation of a fat by the mitochondria since Lorrain 

 Smith ('08) had shown that nile blue stained neutral fat pink 

 in tissue cells. Later it was observed that nile blue B extra 

 only stains fat in the dead and not in the living cell, and there- 

 fore there was no indication that the mitochondria are in any 

 way connected with the formation of fat. 



So far as our observations go they show no direct relation 

 between the mitochondria and the formation of fat, although 

 in some cases there is a coincident change in shape of the mito- 

 chondria with the accumulation of fat droplets. 



Canalicular system 



One of the interesting cytoplasmic structures, the canalicular 

 system, found by other observers, has as yet not been observed 

 in these living cells. 



Bensley ('11) by means of neutral red observed the small 

 canaliculi as clear spaces in the deeply stained pancreatic cell. 



