Manganese Sulphate upon the Growth of Barley. 583 
3. Manganese sulphate, though not an actual toxic to Barley, retards 
the growth very considerably if supplied in moderate quantities. Minute 
traces of the salt have a decided stimulative action both on the root and 
shoot. 
4. When supplied in sufficient concentration manganese is taken up by 
the plant and deposited in the lower leaves. 
In conclusion, I have to express my indebtedness to Mr. A. D. Hall 
for the valuable advice he has given me during the progress of the experi¬ 
ments, and also to Dr. N. H. J. Miller for assisting me by taking the photo¬ 
graphs reproduced in this paper. 
EXPLANATION OF PLATE XLVII. 
Illustrating Miss Brenchley’s Paper on the Influence of Poisons on Barley. 
Fig. 1. Photograph showing the deleterious effect of copper distilled water on the growth of 
plants (Peas). 
1, 3. Peas growing in glass distilled water. 2, 4. Peas in Cu distilled water. 
(No nutrient salts.) 
Fig. 2. A series of barley plants about six weeks old grown in different concentrations of 
copper sulphate in the presence of nutrient salts. 
I. 
Glass distilled water. 
6. 
1 : 100,000 
2. 
Copper distilled water. 
7 - 
1 : 250,000 
3 - 
1 :12,500 C.S. 
8. 
1 : 500,000 
4 - 
1:25,000 „ 
9 - 
1 :1,000,000 
5 * 
1 : 50,000 „ 
Fig. 3. Photograph showing the effect of distilled water, differently prepared, upon the growth 
of plants—Peas. (No nutrients.) 
1. Glass distilled water. 3. Glass distilled water which had been allowed 
2. Cu distilled water. to stand in contact with pure silver for one hour. 
Fig. 4. A series of barley plants grown with varying concentrations of manganese sulphate, in 
the presence of nutrient salts. 
1. Control—distilled water. 4. 1 :1,000,000 M.S. 
2. 1: 10,000 M.S. 5. 1:10,000,000 ,, 
3. 1 : 100,000 ,, 6. 1 : 100,000,000 ,, 
