187 
opposite side (peripheral) the ramifications of the pulmonary vein are 
seen with its radicals running over the tips of the air-cells. No 
distinction as to size has been found between the air-cells of the atrium 
and those of the air-sac. In lobules lying just beneath the pleura 
the capillary net-work in the wall is finer in those air-cells from the 
atrium, than in those arising from the air-sac. 
The older authors led by Mauricut!) and followed by HELvE- 
TIus 2), MAGENDIE *), RAInEY ‘) and others claimed that the air-cells 
communicated, and that the lung was to be compared to a sponge. 
REISSEISEN 5), Barzin®) and a few other writers, claimed that the 
terminal extremity of the bronchus opened into single air-cells, and 
these air-cells were independent of one another. MOLESCHOTT ‘), 
RossıGnoL ®) and KÖLLIKER ?) were the leaders of the theory that 
the bronchi opened into a cavity, the central part of which remained 
free, but the walls were covered with air-cells which opened into the 
central free cavity. HENLE?°) describes communications between ad- 
joining air-cells, but he considers them anomalies. He found them in 
the Jungs of old people, and attributed them to the result of atrophy 
and absorption of the lung substance. The view that there are no 
anastomoses between the air-cells is the one generally accepted. Re- 
cently DELAFIELD has revived the old theory of communication, and in 
this has been supported by RoosEvELT. DELAFIELD !!) says: „The air 
passages seem to be made up of a succession of large vesicles opening 
into each other, or of an irregular larger canal made up of vesicles 
into which other vesicles open from all sides. These air passages 
-branch and anastomose .... They are given off from the sides of 
distal and proximal: the directions at right angles to the bronchus as 
central and peripheral. 
1) De pulmonibus epistolae II ad Borellum, Bonon. 1661. 
2) Mémoire de 1’ Académie royale des sciences, 1718, tome I, p. 22. 
3) Legons sur les phénomenes physiques de la vie, II, p. 37. 
4) On the Minute Structure of the Lungs, 1845. 
- 5) Ueber den Bau der Lungen, Berlin 1822. 
6) Comptes rendus de 1’ Académie des sciences, La structure intime 
du poumon, Paris 1832. 
7) De Malpighianis pulmonum vesiculis, Heidelb. 1845. 
8) Recherches sur la structure intime du poumon de |’ homme, Brux. 
1846. 
9) Handbuch der Gewebelehre des Menschen, Leipzig 1852. 
10) Handbuch der systematischen Anatomie des Menschen, 1873, 
Bd. II, p. 291. 
11) Studies in Pathological Anatomy, New York, 1882, Vol. 1, p. 102. 
