FOR WAGGONER’S BIOLOGY 
37 
this fact have upon the canning of fruit? What relation does the 
yeast plant have to bread raising? Why does cider become 
“ hard ”? 
EXERCISE 42 
“COLDS’" VERSUS GOOD HEALTH 
The outline suggested below m^y be used as the basis of a study 
of some of the health conditions during the winter months. It 
will probably require observations covering a period of from six 
to eight weeks. 
I. Problems. 
1. Determine how many members of your class have had no 
“ colds ” or other troubles of the respiratory tract since the open¬ 
ing of school. Of those who have been so affected, how many have 
lost time from school? The U. S. Public Health Service, in in¬ 
vestigating the occurrence of colds, discovered that during a 
period of six months only ten per cent of a large group of people 
had no colds and that the average annual rate was three and seven- 
tenths colds per year. Suppose you keep a record of such condi¬ 
tions in your class. To do this, you may keep a daily chart for a 
period of six weeks. Plan such a chart. 
The following is suggestive: 
Date 
Duration of “colds” or other 
DISEASES OP THE RESPIRATORY TRACT 
Causes 
Treatments 
USED 
Confinement to 
home (days) 
Remaining period of 
affection (days) 
2. From local and state newspapers make a collection of clip¬ 
pings which refer to health conditions during the period in which 
