9 BULLETIN 123, U. S. DEPARTMENT OF AGRICULTURE. 
lesson and possibly regarding the order of some of the lessons. It 
is not essential that they be given in the precise order in which they 
are here presented and it may be desirable to change the order to meet 
local conditions. Some of the practice work, especially exercises 
which require several days to complete, may be done by the members 
of the class in their homes and the results discussed at the next 
meeting. 
The leader should have at hand for use in every lesson these bul- 
letins of the United States Department of Agriculture: Office of 
Experiment Stations Bulletin 28, revised edition, The Chemical 
Composition of American Food Materials, by W. O. Atwater; 
Farmers’ Bulletin 142, Principles of Nutrition, by W. O. Atwater; 
Farmers’ Bulletin 256, Preparation of Vegetables for the Table, by 
Maria Parloa; and Farmers’ Bulletin 375, The Care of Food in the 
Home, by Mary Hinman Abel. One or two standard cookbooks are 
also desirable to provide variety in recipes, and more detail than 
can be given in these pages. The members of the group should be 
encouraged to consult any books in their homes bearing on the sub- — 
ject and to form the habit of using the dictionary and encyclopedias. 
The queries at the end of each exercise are intended to aid in fixing 
the leading points in the students’ minds. The majority of them 
have to do with facts brought out in the lessons, but some of them 
refer to matters which the student is expecteil to gather from ex- 
perience and thought. 
Plan the practical work carefully. For example, the fire must be 
ready and water heating while the vegetables are being prepared. 
Insist on careful weighing and measuring. Waste nothing. 
By-products should be carefully used, or at least their possibilities 
noted, for conservation and efficiency should be watchwords in the 
kitchen quite as much as in business or national affairs. 
LESSON I. CLASSIFICATION OF PLANTS. 
A great variety of food plants are included under the term “ vege- 
table,” and there are many matters connected with their growth, 
selection, and preparation as human foods that are important in a 
study of their value and uses. The study of them may be conducted 
along a variety of lines, depending upon the use to which the infor- 
mation sought is to be put. For example, they may be studied with 
reference to— 
(1) Their discovery and improvement by man. 
(2) The parts which are desirable for food and their food value. 
(3) The ways in which they are or should be handled and mar- 
kketed. 
(4) The cooking or other kinds of preparation necessary before 
they can be properly used as human food. 
