14 BULLETIN 988, U. S. DEPT. OF AGEICULTUKE. 
In considering the circumstances on this last day of the experi- 
ment with bees it is interesting to recall observations made in the 
study of the effect of ventilation on men, that the sensations produced 
by " bad " air are not experienced when the air is stirred. If this 
indicates an actual difference in physiological conditions in the differ- 
ent circumstances, then it is not inconceivable that something analo- 
gous to this was true of the bees on this day. The stirring of the 
air when the circulation was resumed may have served to remove 
some cause of depression that was effective when the circulation was 
stopped. 
SUMMARY. 
In the colony of bees under observation in the respiration chamber 
the expenditure of energy was reduced to the lowest limit by the 
maintenance of favorable temperature and by the avoidance of all 
disturbing factors, so far as possible. Under these circumstances, 
rarely found in the apiary, the energy produced by the bees, as 
measured by the carbon dioxid and water produced and the oxygen 
consumed, was greater, according to body weight, than that pro- 
duced by a man when working at hard manual labor, when we take 
into consideration the fact that the work was done by only a rela- 
tively few of the bees in the cluster. Even assuming that the work of 
the period were equally divided among the bees, their energy output 
per unit of body weight is higher than that of the average laborer. 
When we take into consideration the fact that usually the bees do 
not have such favorable conditions in winter as these bees had, it is 
clear that the energy output is enormous in the average apiary. 
