370 CHIKANOSUKE OGAWA 
2. Muscle fibers in the alveolar mouths. Kolliker and v. Ebner 
(in man), Sussdorf and Miiller (in domestic mammals), demon- 
strated the muscle fibers in the alveolar mouths. These results 
were contrary to Schulze’s description. I could not find any 
muscle fibers around the alveolar mouths in the lungs of (the bat), 
mole, rat, guinea-pig, rabbit, and goat, while in the lungs of the 
dog and man muscle fibers were demonstrated in some of the 
alveolar mouths and in the lung of the cat, the greater number of 
alveolar mouths showed fairly strong fibers. In the case of the 
cat, the muscle fibers, which depart from the muscle rings around 
the mouths of the alveolar ducts, run in the wall of the alveolar 
ducts in various directions and participate at the same time in 
formation of the muscle rings around the alveolar mouths. There 
are also present circular fibers which are confined to the mouths 
alone. In the lungs of the dog and man one may recognize 
only one or two muscle fibers around the alveolar mouths. There- 
fore, if there are only a few fibers around the mouths of the peri- 
pheral parts of the alveolar ducts, as well as around the alveolar 
mouths, it is hard to decide whether or not such fibers form closed 
rings. 
3. Muscle fibers in the alveolar walls. Existence of themuscle 
fibers in alveolar walls has been confirmed by Piso-Borme (in 
several domestic mammals and man) and Miiller (in sheep and 
oxen), but not by Koélliker and v. Ebner (in man) as well as by 
Schulze and Caradonna (in mammals). Though I could demon- 
strate occasional muscle fibers which originate from the muscle 
rings of the mouths of the alveolar ducts in alveolar walls of the 
lungs of the cat, dog (fig. 26), and man, I could find no such 
muscle fibers in the alveolar walls of the lungs of the other mam- 
mals before mentioned. 
ELASTIC FIBERS 
Though we have several detailed reports concerning the elastic 
fibers of the human lung, as yet no one seems to have undertaken 
an investigation of the whole vertebrate phylum for the purpose 
of comparison. ‘The method used was observation of the lung 
wall and alveolar walls in surface view and in section. They were 
stained mainly in resorein-fuchsin. 
