1913] RIGG—EFFECT OF BOG WATERS 319 
Lake (5 plants), bog spring on Mount Constitution (3 plants), 
Mud Lake (10 plants), well water at Friday Harbor, Washington 
(25 plants). In every one of these cases the root hairs were normal. 
The water from Echo Lake was dipped up by the writer while 
standing on the edge of the Echo Lake bog; it was obtained at a 
distance of 15 feet from where the water from the Echo Lake bog 
was obtained. The bog spring on Mount Constitution referred to 
emerges from the side of the mountain and its water seeps into the 
swamp which gradually merges into the bog. It has the coffee 
color characteristic of bog water, but not to so marked a degree 
as the water obtained from underneath typical bog vegetation. 
Mud Lake is so close to Lake Washington that the two are con- 
nected during the winter season. It is a circular lake about 880 m. 
in diameter. There is some bog vegetation near its southern end, 
and the situation of this vegetation appears to be in a general 
way similar to that of Buckeye Lake bog in Ohio described by 
DacuNnowski (5). The water used was obtained from the edge 
of the lake at a distance of 90 m. or more from the bog vegetation. 
The well water used at Friday Harbor was obtained from a surface 
well near the Puget Sound Marine Station. This is called “tap 
water” in table I, since the effect of the two has been found to be 
identical. 
Plants were also grown in several solutions which it was expected 
would prove toxic. The following list of substances was found to 
produce stunting of the root hairs of Tradescantia of an amount 
and kind comparable with the effect of undiluted bog water: sea 
water diluted with three times its volume of tap water; carbolic 
acid, o.oor per cent; formalin, o.oor per cent; gelatin, 0.001 
©.002 per cent; tea; coffee. In undiluted sea water no roots 
developed. Stronger solutions of carbolic acid and of formalin 
entirely inhibited the development of roots. 
It is of course possible that formalin might develop from the 
slow decay of woody materials in the bog in the absence of oxygen, 
but I have not found any evidence of its presence in bog water. 
We might reasonably expect, also, that tannin would be found in 
bogs, but we have no direct evidence that it is a factor in limiting 
bog floras. 
