MICHIGAN ACADEMY OF SCIENCE. 
67 
merits which give us the right to suppose that these reactions are differ- 
ent from the reactions that occur in a beaker and test tube. 
Aside from the phenomenon of selective absorption which we know 
takes place in soils, we have at our command a number of experiments 
performed by the most distinguished chemists showing that the amount 
and kind of surface possesses marked influence on the reactions. I cite 
here the work of van’t Hoff who concludes that both the nature and the 
amount of surface exposed have an influence. The inversion of sugar 
is affected by the nature of the walls of the containing vessel, and its 
reduction by Fehling’s solution is effected by the walls and the amount 
of cuprous oxide formed in the reaction. In the case of soils where we 
have so large a surface and such thin films, absorption, surface ten- 
sion, and other not-well-defined molecular forces may and will play their 
role.* " 
It follows then that the addition of an excessive amount of water 
to soils (drainage) changes the conditions, i. e. salts that were not in 
solution in the soil solution will be found to be dissolved in the drainage 
water, and we have therefore, the right to suppose that the drainage 
water is different, in a qualitative and quantitive respect, from the film 
water which surrounds the soil particles. It is, therefore impossible to 
make any conclusion, from the analysis of drainage water on the soil 
solution as it exists in the soil, because the dissolving process is probably 
not proportional to the amount of water added. 
On account of the importance of the environment of the soil bacteria, 
a knowledge of the solution as it exists in the soil becomes most urgent. 
And here we may add that this subject does not only concern the lower 
forms of life, but in the case of higher plants also, the study of the soil 
solution promises fruitful results. 
So I have directed mv study towards this theme and have been seek- 
ing a method which would furnish me some soil solution. Here, again, 
we meet with some difficulties which I should like to mention briefly. 
It is absolutely impossible to obtain a comparison between the soil 
solution obtained and the total soil solution, because everv method 
for securing the soil solution can give only a percentage of the total 
solution, as the last traces of soil water are held back tenaciously by 
great forces. 
The method finally adopted consists of the displacement of the soil 
solution by means of paraffine oil. There is something depressing in 
the impossibility of being able to verify our obtained results with the 
reality. 
With the kind assistance of Mr. Itano some experiments have been 
made. Sulphuric acid of known strength was added to carefully washed, 
dry quartz sand. After this paraffine oil was poured on the sand and 
by means of a suction pump the acid was regained. The titration 
showed that the so-obtained acid did not differ from the acid which 
was used in the experiment. I am perfectly aware of the fact that 
this experiment has practically little bearing on soil conditions. The 
fact, however, that our regained solution had the same composition as 
the original employed solution does not mean that our method is not 
permissible. 
There must be considered, then, the nature of the medium with which 
* F. K. Cameron, The Soil Solution. 
