44 
Transactions Texas Academy of Science. — 1907. 
needs for phosphoric acid and other plant food by means of pot experi- 
ments. But for certain types of soils which give up less than a certain 
quantity of phosphoric acid to weak solvents, we shall no longer make 
pot experiments to test for deficiency in phosphoric acid. We are satis- 
fied to say that such soils are highly deficient in this form of plant food. 
Our work must be continued in other and richer soils, but when I say 
that soils in these classes are widely distributed in the South, you will 
appreciate the step forward we have made on the long road we have yet 
to travel before we reach the solution of the problems concerning the 
phosphoric acid in the soil. 
