iP. CHRISTIANNA SMITH 
In his study of the lipoid content of epithelium, cartilage, and 
muscle fibers of the ox, E. T. Bell (09) makes some observations 
on the lipoids present in the kidney, and finds that the renal 
cells of some ox foetuses contained lipoid droplets, and that the 
cortical renal cells of two large steers were loaded with lipoids.! 
Other observations, not his own, are recorded by Bell in this 
paper. Aschoff (’97) and Pfeiffer (99) described lipoids in the 
kidney and other organs of new-born children; Hansemann (’97) 
found fat, 1) in the human kidney, an occurrence which he 
considered usually pathological, but which might be normal; 2) 
in swine, especially when fattened, which he thought abnormal 
and analogous to obesity in man; 3) in cats and dogs. In 1910, 
Bell examined the tissues of calves, cats, dogs, rats, and frogs, 
and found usually a large number of lipoid droplets in the con- 
voluted tubules, a fewer number in the collecting tubules, and 
in some tubules none. He observed also that the amount of 
lipoid in the kidney varies greatly, the cat showing the greatest 
amount, and the ox least. In his work, “‘On the Differential 
Staining of Fats” (1415), Bell used the kidney tissue of human 
and rat as one kind of material. 
Policard mentions in most cases in his work on the histogenesis 
and histology of the renal epithelium only the presence of lipoids. 
In his paper on the “Functioning of the Kidney of Frog’”’ (10), 
he makes, however, the following summary of his observations 
in regard to the lipoids in the convoluted tubules. The forma- 
tions of lipoids which reduce osmic acid, but which stain with 
copper hematoxylin, after the method of Weigert-Regaud, are 
of three kinds: First, there are flakes of material which stain 
gray that are enclosed in vacuoles. These are, by him, con- 
sidered artifacts. Secondly, very fine granules are present which 
stain blue-black and which correspond to the innermost sub- 
cuticular vacuoles described by various observers, but whether 
it is the wall of the vacuole or the substance contained which 
stains he does not know. ‘Thirdly, in the region of the nucleus, 
1 The term ‘lipoid’ has been substituted here wherever Bell has used the word 
‘fat,’ although he uses ‘fat’ in the general sense to include true fats and other 
lipoids. 
