354 CHIKANOSUKE OGAWA 
first also appeared unsatisfactory, because the large, flat cells 
are exceedingly thin and it is impossible to decide whether the 
nuclei, which are stained, belong to the subepithelial cells or 
to the epithelial cells themselves. But after further attempts 
I happened to obtain a preparation which showed a large, flat 
cell containing no nucleus within its limiting cement lines owing 
to lack of subepithelial cells here. This image proves that the 
large, flat cell has no nucleus. I applied the third method at 
the mouth of the alveolar ducts. Here the several kinds of fiber 
bundles run circular and accordingly the subepithelial nuclei are 
poor, so that I affirmed several times the fact that the epithelial 
cells are here non-nucleated. 
Lange has investigated the respiratory epithelial cells in an 
experimental way, but it seems to me that his work is open 
to criticism from several points of view. He bled rabbits, ex- 
tracted the lungs, injected them with isotonic salt solution, and 
collected the liquid running off from the tracheal stump and that 
obtained by slitting the surface of the lung. He then centri- 
fuged the liquid and studied the residue microscopically. The 
following are my arguments against his work: 
1. In the rinsed liquid he found alveolar (respiratory) epi- 
thelial cells, endothelial cells from blood-vessels, polymorpho- 
nuclear leucocytes and red blood-corpuscles. I should think 
that epithelial cells of the bronchioles and mononuclear leuco- 
cytes ought to have been present also. When these cells are 
in normal position, they may be easily distinguished, but when 
isolated, it is impossible to judge from what part of the lung some 
of them came. I have injected the trachea with several macera- 
tion liquids, cut the surface of the lung after some hours, and 
examined the escaping fluid, but I could see only one kind of 
round nucleated cells. Naturally it is impossible to distinguish 
them, though there must be different kinds. 
2. The alveolar epithelial cells, which were described and 
figured by Lange, are all nucleated. He did not seem to recog- 
nize the fact that there are two kinds of respiratory epithelial 
cells. It therefore seems that Lange started his work with some 
fundamental mistake, which renders his further experiments 
unreliable. 
