VOLUMES, CORTEX AND MEDULLA, ADRENAL GLAND 293 
TABLE 1 
AGE  |VOLUME OF BOTH GLANDS|THE RATIO OF THE PEPE RENCE OX 
ESTIMATED VOLUME or  |YOLUME BETWEEN 
104.0 71 =: {17.60 | 1.00 |16.60 
192.0 112. _|17.90 | 1.50 |16.40 
OR etaiax: Bobs THOT DE eR THM MED ULNA ros Pee oe 
BER WEIGHT eee LEFT ADRENAL. 
Leyes Total dulla Cortex THE a ee H eae 
en RRNA OO za60 (gn || pe ominellh’ percent Ont eter tent 
1 M 4.6 1 0.825} 0.095} 0.730 33 4.0 
2 F 5.9 2 1.042} 0.114} 0.928 10.2 20.0 
3 M 17.0 14 2.010} 0.260} 1.750 13.0 4.0 
4 F a0 16 2.130) 0.200) 1.930 9.1 11.0 
5 M 26.0 29 ~ | 5.370} 0.580} 4.840 9.8 12.0 
6 F 28.0 29 5.49 | 0.39 | 5.10 G2, 20.0 
1h F BY (al) 35 7.35 |0.53' | 6.82 iad 15.0 
8 F 39.0 35 7.55 0.61 | 6.94 8.0 8.0 
9 M 39.0 38 7.46 | 0.60 | 6.86 8.0 —0.2 
10 M 50.0 45 7.06 | 0.50 | 6.56 7.0 2.0 
11 M 7A \0) 55 10.68 | 0.87 | 9.81 14.0 
12 F 79.0 64 16.70 | 1.20 |15.50 11.0 
13 M 
F 
M 
8.2 
6.9 
103.0 69 {11.51 | 0.81 {10.70 7.0 —17.0 
6.0 
8.2 
16 | Damaged in prepa- 
ration 
AT El e20SeOhN, 202) 1830) |) 2.2: | 20:8 6.6 12 
18 Tumor of the adrenal 
19 M | 300.0 | 2SO ye 2b 2 | S2e 2° O20 10.2 18.0 
The values for the volume of the cortex were obtained by subtracting the 
volume of the medulla from that of the total gland. 
The results of my observations are shown in the accom- 
panying table 1 and the four charts. All figures are for the sum 
of the two adrenals of each rat. In this connection it is worth 
noting that in fifteen out of the seventeen rats the left adrenal 
was larger than the right; exceeding it in volume by an average 
of about 10 per cent and in one case by as much as 20 percent. 
Chart 1 shows the change in the volume of the cortical and 
medullary material in the gland of the rat from birth to nine 
months—5 to 300 grams. The values were gotten by finding 
out what fraction of the whole gland was composed of medulla 
and reducing that fraction to its percentage value. The values 
