December, ’23] 
CAMPBELL: NICOTINE DUST PROGRESS 
499 
An interesting fact has occurred as a result of the rapid increase of 
nicotine dusting. It might be supposed, because of the large amount 
of nicotine used in the dust form, that liquid spraying with this material 
had decreased. On the contrary, the use of nicotine in dust form 
seems actually to have stimulated its use as a liquid spray, for more is 
being sold for this purpose than ever before. 
Another development is a stimulation of the use of ground tobacco 
dust. Some manufacturers have advertised this material, but because 
of the variable amount of nicotine in ground tobacco and also because 
it does not volatilize so readily, its use has not been entirely successful. 
Recent experiments performed in New York with a finely-ground tobacco 
indicate that while on the basis of its nicotine content, ground tobacco 
is more expensive and slightly less active than nicotine dust, yet it 
gives sufficiently satisfactory results to be worthy of further investi¬ 
gation. 
For several years the source of nicotine for ah dusts was a solution of 
nicotine sulphate containing 40 per cent of nicotine. With this it was 
customary to use seme hydrated lime, or other “active” material, 
which caused a reaction and liberated the nicotine. Recently some 
manufacturers are utilizing a solution of free nicotine which eliminates 
the need of using an “activator.” There is a tendency also toward the 
use of a solution containing a higher percentage of nicotine. Some 
manufacturers claim better results with the free nicotine than with the 
sulphate, while others who continue the use of the sulphate, maintain 
that it is the most satisfactory. The free nicotine solution is a little 
more expensive, and the increase in the concentration of nicotine also 
increases its cost per unit. Recent experiments in New Jersey have 
demonstrated that a dust made of dolomite and free nicotine gave a 
better killing than one composed of hydrated lime and nicotine sulphate. 
The superiority of the free nicotine dust was due to a greater evolution 
of gas in a given period of time. It has also been demonstrated that 
nicotine sulphate in a dolomite carrier releases its nicotine more rapidly 
than in hydrated lime, so that the comparison of the two types of 
nicotine in two different carriers is not conclusive. 
A certain amount of moisture is desirable in nicotine dust when 
compounded with nicotine sulphate, as the reaction is thereby hastened, 
but too much moisture is disadvantageous, because some of the nicotine 
may be dissolved. It is difficult also to thoroughly incorporate such a 
quantity of liquid into the carrier, without resulting in a dust which is 
too moist for satisfactory application. The presence of moisture is 
