2 BULLETIN 521, U. S. DEPARTMENT OF AGRICULTURE. 
of another. For example, lessons are outlined covering wheat, rice, 
and cane. It is not expected that these topics will be of equal im- 
portance in any one district. Where rice or cane is important it may 
not be necessary to treat wheat as a lesson, in which case more time 
may be given the other crops. 
Adaptation to students. — The lessons should be adapted to the needs 
and capacities of the students. Particular care should be taken with 
those lessons dealing with the science underlying agricultural prac- 
tice that the subject be kept within the range of secondary students. 
For example, students may get a comprehension of how plants grow 
and the principles which underlie plant breeding without going into 
technical plant physiology and genetics. Likewise, as an aid to a 
better understanding of the practice of feeding, students should 
know the simpler aspects of digestion and assimilation and under- 
stand the basis for scientific feeding, yet preliminary lessons on these 
subjects need not involve anything beyond very elementary chemistry 
and physiology. The extent to which these lessons are considered will 
depend upon the maturity of the students and their training in 
elementary science. 
USE OF TEXTS AND REFERENCES. 
It is hoped that the outlines with the references given will keep 
the instructor from following a textbook too closely. A list of books 
for use as general references is given at the end of each course. While 
the students may be required to buy one or more books during the 
course, these texts should in all cases be supplemented and adapted to 
both the student and the community by making special assignments to 
other references. Special references to bulletins of this department 1 
are given with nearly every lesson. It is expected that publications 
of the State agricultural college, experiment station, or board of 
agriculture will be used also, especially the bulletins of the State in 
which the school is located. It is assumed that the school will main- 
tain files of such publications of their own State as pertain to agri- 
culture, the Yearbooks of the United States Department of Agri- 
culture, and all Farmers' Bulletins pertaining to the agriculture of 
the district in which the school is located. Reference material should 
be secured early so that it will be available as the lessons are taken up. 
1 Farmers' Bulletins and Yearbooks of the United States Department of Agriculture may 
be obtained free as long as the supply lasts, on application to the Secretary of Agricul- 
ture, Washington, D. C, or to any Senator or Representative in Congress. Other pub- 
lications of the Department of Agriculture and those named when no longer available for 
free distribution may be obtained from the Superintendent of Documents, Government 
Printing Office, Washington, D. C, at a nominal price. Price lists covering various Gov- 
ernment publications may be obtained free from the Superintendent of Documents. Each 
teacher should secure a copy of Price List No. 16, which includes Farmers' Bulletins, 
Yearbooks, and department bulletins of the United States Department of Agriculture. 
Lists of these publications prepared for teachers may be obtained from the agricul- 
tural instruction division of the States Relations Service. 
