458 SANITATION 



14. In what sense is the growing of clover, alfalfa, etc., an inocula- 

 tion of the soil? (Cf. 56). 



15. How does the formation of toxins in the soil resemble their 

 production in the blood? 



16. If you were planning to disinfect a room with formaldehyde, 

 suggest how you would place books, so that the germicide could really 

 get at them; closets; bureaus and dressers; bedding; clothing. What 

 precautions would you take regarding cracks around doors, etc.? 



17. Why does a dilute sugar solution, such as a fruit sauce, need to 

 be so carefully sterilized and kept away from the air, while a con- 

 centrated sugar solution, such as a preserve, does not? 



18. Would you say that sanitary housekeeping is a simple or a 

 complex problem? Is it worth while? 



