1915] ROSE—APPLE BARK 61 
extract of healthy Ben Davis bark, sample 17. The apparatus 
contained the following solutions: 8, 9, 10, with 1 cc. extract 
(acidity reduced one-fourth)+1 cc. H.O+4 cc. 1 per cent pyro- 
gallol; 13, with 6 cc. distilled water; 11, 12, with 1 cc. extract 
(acidity reduced one-half)+1 cc. H,O+4 cc. 1 per cent pyrogallol. 
The results are given in table IV. 
TABLE IV 
MANOMETER READINGS IN EXPERIMENT NO. 3; EXTRACT OF HEALTHY BARK, SAMPLE 17 
MANOMETER READINGS CORRECTED AGAINST AN APPARATUS 
“ CONTAINING ONLY WATER 
ELarsepD | TEMPERA- 
Day oF| Time or TIME IN | TURE AT 
TEST | READING .|HOURS AND| TIME OF Three-fourths acid One-half acid | HO 
UTES READING | 
8 9 b te) Ir 12 | 13 
Ist ..| 4:40PM.) 0* 33.0 .00 | 0.00 | 0.00} 0.00] 90.00 | 0.0 
2d...) 9:20A.M.| 16:4 33-0 j—1.16 |—1.14 |—0.89 |-—-1.34 |-—1.32 | 0.0 
10-00 A.Msl 17°20 |. 32:0 E,YO 2,37 (1 Of 1-855 [1.40 19.0 
4:55 P.M.| 24:15 33.5 |—1.31 |—1-190 |—1.14 |— 4.69 |—1.74 | 0.0 
4th...| 3:50Pp.M.| 71:10 | 34.0 |—2.05 |—1.82 |—1.96 |—2.59 |—2.64 | 0.0 
5th...) 1:40 P.M. 32.0 2.39 |—2.27 |—2.39 |—2.92 |—2.92 | 0.0 
6th.../ 4:35 P.M.) 119:55 | 32.0 |—2.51 |—2.39 |—2-59 |—3-33 |—3-33 | 9.0 
7th...| 4:20 P.M.) 143:40 | 33.8 |—2.71 |—2.69 |—2.84 |-3 —3.42 | 0.0 
8th...) 5:50 P.M.) 169:10 | 34.5 2.94 |—2.84 |—2.99 |—3.49 |—3-59 | 0-0 
gth. 8:12 A.M.| 183:32 $3.1 |--2.04 |~-2.84 [3.09 [3-74 [3-79 | 0-0 
RRR oy in incubator at 3:10 P.M.; apparatus closed and shaken at 4:40 P.M.; shaken again the next 
Experiment 4 was arranged with extract of diseased Ben Davis 
bark, sample 15, as follows: 12, with 1 cc. extract unchanged 
(acidity 0.38)+1 cc. H.0+4 cc. 1 per cent pyrogallol; 11, with 
6 cc. distilled water; 8, 9, with 1 cc. extract (acidity 0. 29)+1 cc. 
H.0+4 cc. 1 per cent pyrogallol. It was thought desirable to run 
the reactions thus close together (see table V) to test the effect 
of very small differences in acidity on the rate and total amount of 
oxidation. The results are given in table V, which summarizes 
the results from all the experiments described above and from others 
duplicating them in various ways but not described in detail in this 
paper. 
A study of table V shows that when results are averaged from 
several different experiments the statement made earlier still holds, 
that unchanged extract of diseased bark causes greater and more 
