86 CHRISTIANNA SMITH 
Ten per cent formalin and scarlet red. No granules were 
preserved in the proximal convoluted tubules in most regions. 
Some red-staining droplets were found in the tubules bordering 
the medullary ray and in the medullary loop and collecting 
tubule. 
Ten per cent potassium dichromate and sudan III. The cyto- 
plasm of the cells of the proximal convoluted tubule stained 
diffusely with red and contained irregular masses which might 
be called sudanophile precipitate by Bell (1415) or perhaps, 
lipoids which have become dissolved in the cells during the fixation 
with application of heat. The lipoid granules in the ascending 
and descending limbs of the medullary loop and in the collecting 
tubules showed clearly. 
Ten per cent potassium dichromate and osmic acid. The lipoids 
which blackened with osmic acid were present as fine granules 
in the ascending limbs of the medullary loop, and the lower 
portions of tubules which were interpreted as the medullary 
segments of the proximal convoluted tubules and were found in 
the labyrinth bordering the medullary ray. In the ascending 
limbs of the medullary loop in the cortex, the granular rods 
which were so clear in the medulla of the cat, were present, 
though not preserved in the medulla (fig. 11). In 1 per cent 
osmic acid, the rods in the ascending limb appeared homogeneous. 
Rabbit 
As the kidney of the dog differed from that of the cat in its 
lipoid content, so also is the kidney of the rabbit different from 
both of them. Kidneys of eleven rabbits were examined which 
had been fixed in Benda’s fluid, and no lipoids which would reduce 
osmic acid were observed. Four of these rabbits were from seven 
days to seven and one-half weeks old, and observations made on 
the kidney of the seven and one-half weeks old rabbit will be given. 
‘The older rabbits whose ages were unknown were affected with 
coccidiosis, but the young rabbits were normal and healthy. 
Fresh tissue. The cells of the tubules contained fine red 
granules when stained with scarlet red and some tubules con- 
