1908] CROCKER AND KNIGHT—CARNATIONS 265 
injury to the plant through the absorption of gas by the soil and later 
by the roots. Also no definite determination of the toxic limit of the 
gas can be made, for the amount absorbed by the soil is not determi- 
nable. 
To avoid such sources of error the buds and flowers still intact 
were exposed indiv idually to the desired concentrations of the gases. 
This was accomplished by the use of the apparatus shown in fg. I. 
Fic. 1.—For description see text. 
The bottle a is furnished with a three-holed rubber stopper. In one 
hole of the Stopper is a straight glass tube reaching nearly to the 
bottom of the bottle. A calcium chlorid tube (d) is attached to the 
Projecting end of this tube by means of a rubber tube furnished with 
: pinchcock ( (e). In the second hole of the stopper is a short bent glass 
tube (f), the outer end of which is furnished with a rubber tube and 
Pinchcock (g). The third hole in the stopper is small and is capable 
- having the stem of the carnation inserted from the side by a split, 
Which Teaches from the hole to the margin of the cork. In setting 
