PHYSIOLOGY. 269 



zens, moving in and out. As this hard duty has 

 no intermission during the day, nor in hot weather 

 during the night, and must necessarily occasion 

 fatigue, one set of ventilators is considerately re- 

 lieved in about twenty-five minutes, by another set 

 of fresh bees. Under particular circumstances 

 the number of ventilating bees is considerably in- 

 creased. " When the air," says HUBER, " was 

 not renewed in the manner desirable, we have seen 

 all vibrating their wings at once, though this never 

 occurs in the natural state, when the vibrations 

 of a few are sufficient for ventilation." Although 

 this fanning motion of the wings is so rapid as to 

 render them almost indistinguishable, yet they 

 may be observed to describe an arc of 90. The 

 sagacious bees remind me of a method which is 

 sometimes adopted of renewing the air of a room, 

 called pumping ; some person moves the door 

 backward and forward so rapidly as to cause a 

 thorough agitation of the confined air, and the in- 

 troduction of a fresh unvitiated atmosphere. 

 61 When they are engaged in ventilation, the bees 

 by means of their feet and claws, fix themselves 

 as firmly as possible, to the place they stand upon. 

 The first pair of legs is stretched out before ; 

 the second extended to the right and left : whilst 

 the third, placed very near each other, are per- 

 pendicular to the abdomen, so as to give that part 

 considerable elevation." That ventilation is carried 



