_III. Sub-topic 2.--Our interest in controlling them; the methods based on mode and conditions of growth, etc.:_ (_a_) Prevention: Eliminating favourable conditions; low temperature, high temperatures, cleanliness; sewerage disposal; clean cow-stables, cellars, kitchens, etc.; antiseptics--carbolic, formalin, sugar for fruit, sealing up; quarantine, vaccination, antitoxin. (_b_) Cultures,--alfalfa, cheese, butter, under control. GEOGRAPHY OF EUROPE _I. Topic.--Europe:_ What interest to us; why we study it; position, latitude, near water, boundaries, size; Surface features--highlands, lowlands, drainage rivers, coast-line, etc. Climate--temperature (means, Jan., July), wind, moisture. _II. Sub-topic 1.--Products (based on above conditions):_ Vegetation, animal, mineral; vary over area according to physical climatic, and geological conditions; Kinds of products of each class, in each area, etc. _III. Sub-topic 2.--Occupations (based on Lesson II):_ Study of operations and conditions favourable and unfavourable under which each product is produced, gathered, and manufactured. Industries, arising from work on the raw materials. _IV. Sub-topic 3.--Trade and Commerce (based on Lessons II and III):_ Transportation, producers selling and manufacturers buying raw material, distributed to homes in country and city, to factories within the region itself, to regions beyond, across oceans, etc. Manufactured products sent out, exports and imports. _V. Sub-topic 4.--Civil advantages (based on Lessons I, III, and IV):_ Conditions of living--homes, dress, work and pleasure; trades, education, government, social, religious, etc. PARTS TO WHOLE The method of whole to parts cannot be followed in all cases even where a number of lesson units may possess important points of inter-relation. Although, for instance, simple and compound addition and addition of fractions are only different phases of one process, no one would advocate the combining of these into such a unified lesson series. In Canadian History, also, although the conditions of the Quebec Act, the coming of the United Empire Loyalists, and the passing of the Constitutional Act, have definite points of inter-relation, it would nevertheless be unwise to attempt to evolve these out of a single complex lesson unit. In such cases, therefore, the synthesis of the various parts must be made as the lessons proceed. Moreover, it is well to ensure the complete organization of the elements by means of an outline review at the end of the lesson series. The student-teacher will meet an example of this process under the topical lesson in Chapter XVII. PRECAUTIONS It is evident from the above considerations, that certain precautions should be observed in deciding upon the particular subject-matter to be included in each lesson topic.