MR. ADDISON ON THE AIR-CELLS OF THE LUNGS. 
163 
youth and the large cells of old age, I found them varying from ^^th to smooth °f an 
inch ; the largest oval foramina were from ^ 0 -th to -g^th of an inch, some were from 
Tcroth to xyo th of an inch? and there were others less. In dried and inflated prepa- 
rations, the cells and foramina being fully distended with air, measure more than 
when the preparations are fresh and recent. On the other hand, in injected prepa- 
rations, the vessels being distended, the cells and foramina measure less. 
Explanation of the Plate. 
PLATE XII. 
Fig. 1 . A thin section of dried and inflated lung, showing large oval foramina pro- 
duced by dividing the lobular passages ; (b, b) several oval foramina close 
together, the section having passed very near to the point whence the pass- 
ages branch off. Subjacent cells and foramina are seen by looking down 
through the uppermost foramina (c, c). 
Fig. 2. Oval foramina seen in a section of inflated and dried lung made at the surface 
and including the pleura ; they are somewhat smaller, and placed at more 
equal distances from each other than in the preceding figure. 
Fig. 3. A thin section of recent and macerated lung, slightly extended, showing sec- 
tions of cells and lobular passages ; (a, a , b) a series of communicating 
cells. 
Fig. 4. A small portion of the thin edge of a lung of a Rabbit injected partially with 
mercury, showing a mass of minute globules in a fully injected lobule (a), 
and nodulated or beaded branches in others (b). The nodules being cells 
communicating with each other by lobular passages ; the branched symmetry 
is lost in a mass of globules at c. 
Figs. 5 and 6. Small sections from the thin margin of the lung of a foetal Calf, 
magnified about three diameters. The lobules are compressed and spread 
out by pressure between two plates of glass. Several bronchial tubes are 
filled with mercury ; they gradually assume a nodulated appearance, and at 
length in the interior of the lobules terminate in cells and lobular passages. 
Fig. 7- A more magnified view of the branchings of the intralobular bronchial rami- 
fications. The mercury has been urged on by increased pressure, so as to 
fill a greater number of ramifications, which at (a) have become so nume- 
rous that their symmetry is lost in the multitude of globules. 
Fig. 8. Intralobular bronchial ramifications, partially inflated and highly magnified. 
(<?). Cals de sac terminations lying against the lateral inflations of adjoining 
branches. ( b , b , c). The multilocular culs de sac at the surface of a lobule. 
Fig. 9. Shows the cells formed upon the intralobular bronchial branches, with po- 
lyhedric figures formed by pressure. 
y 2 
