VENTILATION. 
89 
ing, an equal current will force its w r ay into the other, and 
the lamp will burn until the oil is exhausted. 
It is on this principle of maintaining a double current 
by artificial means , that bees ventilate their crowded 
habitations. A file of ventilating bees stands inside and 
outside of the hive, each with head turned to its entrance, 
and while, by the rapid fanning of their “ many twinkling” 
wings, a brisk current of air is blowm out of the hive, an 
equal current is drawn in. As this important office de- 
mands unusual physical exertion, the exhausted laborers 
are, from time to time, relieved by fresh detachments. If 
the interior of the hive permits inspection, many ventila- 
tors will be found scattered through it, in very hot weath- 
er, all busily engaged in their laborious employment. If 
its entrance is contracted, speedy accessions will be mado 
to their numbers, both inside and outside of the hive; and 
if it is closed entirely, the heat and impurity quickly in- 
creasing, the whole colony will attempt to renew the air 
by rapidly vibrating their wings, and in a short time, if 
unrelieved, will die of suffocation. 
Careful experiments show that pure air is necessary 
not only for the respiration of the mature bees, but for 
hatching the eggs, and developing the larvae ; a fine net- 
ting of air-vessels enveloping the eggs, and the cells of the 
larv* being closed with a covering filled with air-holes. 
In Winter, if bees are kept in a dark place, wdiich is 
neither too warm nor too cold, they are almost dormant, 
and require very little air ; but even under such circum- 
stances, they cannot live entirely without it ; and if they 
are excited by atmospheric changes, or in any way dis- 
turbed, a loud humming may be heard in the interior of 
their hives, and they need almost as much air as in warm 
weather. 
If bees are greatly disturbed, it will be unsafe, espe- 
