232 DR. E, KLEIN, 
Had I found these ciliated cells in an isolated state, 2.e. 
after teasing out little bits of kidney substance, I should 
have taken them to be identical with the cells figured by 
Heidenhain (‘ Hermann’s Physiologie,’ v, p. 285, fig. 67) of 
the kidney of the rat, but in our case the cilia are projecting 
from the cell substance into the lumen of the tubule, the 
cell substance showing, in addition, the rods of Heidenhain, 
and there being a definite boundary line between the cilia 
and the cell substance. 
The following are measurements made on tubules lined 
with ciliated epithelium : 
1. Transverse diameter of the whole tube 
(lumen and wall) in cross section . . 0°0414 mm. by 0°0486 mm. 
Thickness of the epithelial lining without 
the cilia : 4 A : : . 00054 ,, 
Length of the cilia . ‘ : 2 », A OUGO 5: 
2. Transverse diameter of the tube 4 - 0:0396 ,, 
Thickness of the epithelium . : - U0U4 .. 
Length of the cilia . : : ° . 00036 ,, 
3. Transverse diameter of the tube . 0°0324 ,, 
Thickness of the epithelium . : 7 OUUse" a 
Length of the cilia . : é : 20004, "3; 
4, Transverse diameter of the tube : . 0°032 ,, by 0°045 mm. 
Thickness of the epithelium. : . 00054 ,, 
Length of the cilia . ; ; ; . 00038 ,, 
5. Transverse diameter of the tube ot -O°0362" by 
Thickness of the epithelium . - « 00072 ,, on one side. 
Length of cilia : , : ‘ . 000386 ,, ? 
Thickness of the epithelium P . 0°005 _ ,,on the other side. 
Length of the cilia . ; : i . O005" 3 be, 
Ciliated epithelium, as far as I can find in the literature 
of the kidney, has not been seen in the mammal’s organ ; in 
that of reptiles, amphibia, and fishes as is well known 
(Bowman, Remak, Kolliker, and others), ciliated epithe- 
lium is of a constant occurrence in the capsule of the Mal- 
pighian corpuscle, and especially in the long thin neck of 
the urinary tubule; the cilia are here of very great length, 
and their movement has been observed in the fresh state by 
Duncan (Sitzungsber. d. Akad. d. Wiss, Wien Abtheil. 56). 
and Spengel (‘ Arbeit. aus d. Zoolog. Instit.,? Wurzburg, 
1876). I have tried to see the movement of the cilia in 
sections through the fresh kidney of the mouse, but have 
not hitherto been successful. The sections were made 
immediately after killing the animal and were examined in 
aqueous humor, but the urinary tubules of the cortex were 
always so contracted that of a lumen of the tubules, and 
