378 OLDENBUSCH: STIMULATION OF PLANTS 
Botanical Laboratories of Barnard College, under the super- 
vision of Professor H. M. Richards, for whose advice and assis- 
tance the writer is greatly indebted. 
- In this work, while no attempt was made to cover every type 
or condition of plant tissues, a number of widely differing kinds 
of material were employed. The experiments fall into three 
groups, each of which could profitably be elaborated beyond 
what was attempted here. These three categories are as given 
below and will be considered as separate topics in the following 
discussion. 
1. Stimulation of seeds and seedlings. 
2. Stimulation of buds 
3. Stimulation of certain fungi. 
Carbon disulphide is a clear, practically colorless liquid when 
pure, very inflammable and volatile. It has a disagreeable odor, 
especially when impure, because of the decomposition into other 
sulphur compounds, hydrogen sulphide in particular (see Graham, 
20). It is soluble in all proportions in alcohol, ether, and chlo- 
roform, but only slightly soluble in water. The solubility in 
water, according to Graham, varies inversely as the temperature, 
as follows: 
At iz -13° €. 2.0 gms. CS dissolve a I liter ot water. 
I 
27° “ce 168 “ec 6é “cc oc I ce “c “ce 
30° 33° “ 1.45 “c “ Toe se c tc 
From these data, it was estimated by interpolation that at 
20°-22° C. (average room temperature) about 1.8 gms. CS: 
dissolves in 1 liter of water. 
In the following paper, the concentrations of the solutions 
used were determined in terms of molecular solutions. The 
molecular weight of carbon disulphide is 76.125, and if 1.8 grams 
dissolve in 1 liter of water at approximately room temperature, 
then a saturated aqueous solution is 0.0235 of a molecular solu- 
tion. More dilute solutions were prepared from this, in fractions 
varying by 1/2000M. No attempt was made to determine or 
maintain the exact concentration closer than this, because carbon 
disulphide is so easily vaporized and a certain amount of that in 
solution is continually volatilizing out. In cases where the ex- 
periments lasted over a few days, the pean were renewed at 
intervals of two or three days. 
