MICHIGAN ACADEMY OF SCIENCE. 
209 
IS TOXICITY A FACTOR IN SOIL PROBLEMS? 
A. Dachnowski. 
[Abstract.] 
Various attempts have been made to account for the physiological dryness 
of bog habitats. The study here reported in part, and of which a more 
extended account will appear in the Botanical Gazette, may be summarized 
as follows: — 
(1.) Osmotic pressure and acidity determinations of bog water from 
a bog island in a lake near Columbus, Ohio, reveal conditions similar 
to those found in Michigan bogs. 
(2.) The bog island under consideration consists of peat forty feet 
in depth. Its surface vegetation has largely northern bog forms and 
presents two distinct zones. The bog island is virtually a water cult- 
ure on a large scale. A series of cultivated plants when grown on the 
bog, show very marked dwarfing and various xerophilous characters. 
(3.) A series of experiments in the form of bog water cultures vari- 
ously treated gave the following transpiration data: — 
PERCENTAGE INCREASE IN TRANSPIRATION. 
Culture solution. 
Wheat. 
Corn. 
Shaseo- 
lus mull. 
Vicia 
faba. 
Elm. 
Buckeye. 
Cowpea. 
Oats. 
Trades- 
cantia. 
I. Central zone: 
1. Bog soil extract* 
0 . 
0 . 
0 . 
0 
0 . 
0 
2. Bog water untreated 
19. 
10 . 
113. 
22. 
68. 
0 
0 
9 S 
3. Bog water aerated 
55. 
27. 
201. 
1 .3 
20 
3 4 
4. Bog water neutralized 
209. 
91. 
ioo. 
8 (> 
5. Bog water filtered 
245. 
52. 
225. 
215. 
94 
38.8 
42 
24.7 
(j. Bog plant-water 
54. 
22. 
184. 
II. Maple-alder zone: 
1. Bog soil extract* 
0 . 
0 . 
0 . 
0 
2. Bog water untreated 
38. 
05. 
287. 
90 
3. Bog water aerated 
104. 
71 . 
44 
4. Bog water neutral 
298. 
136. 
335. 
148. 
5. Bog water filtered 
256. 
70. 
b. Bog plant water 
11. 
40. 
178. 
113. 
*4 grs. of bog soil extract and 400 cc. distilled water. 
(4.) The corresponding differences in form and general appearance 
of some of the plants are illustrated in the accompanying plates. 
(5.) The plants grown in the solutions treated with CaCo 3 and 
carbon black show not only accelerated growth and an increase in trans- 
piration, but also an increase in dry weight. The increase in dry matter 
produced varied from 20% to 50% and more. 
(6.) That the response to toxic bodies when present in small amounts 
may lead to acceleration of growth is also evident in connection with 
a biometric study on the annual wood-increment in Acer rubrum. 
