That the building-up process depends on the action of molecular forces comparable to those by which a growing crystal goes on selecting atom-complexes of its particular kind from the solution around seems highly probable, and this being the case we can understand how under certain circumstances Substitutive selections may occur.
"Disease in Plants"
H. Marshall Ward
Better pastoral work by the teacher, a closer co-operation with the home, and Substitutive-not prohibitive-measures avail much in meeting this difficulty.
"Training the Teacher"
A. F. Schauffler Antoinette Abernethy Lamoreaux Martin G. Brumbaugh Marion Lawrance
The Substitutive measures here again are the only wise and effective ones.
"Training the Teacher"
A. F. Schauffler Antoinette Abernethy Lamoreaux Martin G. Brumbaugh Marion Lawrance