500 



GLEANIN(iS IN BEE CULTURE 



Aug. 15 



FIG. 2. — LARGER TRACHEAS 



SHGWIXG THE ClIITINOUS SPIRES WHICri 

 FROM COLLAPSING. 



PREVENT THE TUBES 



phere contains about one-fifth of oxygen and 

 four-fifths of the indifferent nitrogen, other 

 gases being present only in insignificant 

 quantities. The combustion of organic mat- 

 ters furnishes, as we said above, chiefly car- 

 bonic acid, a heavy gas which is poisonous, 

 even to a deadly degree, if it accumulates in 

 great quantities in the body. The other aim 

 of the respiration, then, is to remove this in- 

 jurious gas from the body. Respiration, 

 therefore, brings oxygen to the animal cells and 

 removes from them the carbonic-acid gas. This 

 result is accomplished by means of the fact 

 that the cells are brought into close contact 

 with the surrounding medium, whether it is 

 atmosphere or whether it is water, since wa- 

 ter always contains quantities of oxygen in so- 

 lution. The cells are separated from this 

 medium by only an extremely finely woven 

 skin through which the gases may easily 

 pass. The exchange of gases takes place 

 across this minute skin in such a way that 

 the carbonic-acid gas of the body is rejected 

 while oxygen is mtroduced. In the verte- 

 brates this exchange is done in the proper 

 organs— the lungs or gills. The blood brings 

 the oxygen into the various parts of the body, 

 so that the system of circulation of the blood 

 is very perfect and complicated. With the 



bees, on the contrary, the air itself comes to 

 all the cells and parts of the body, reaching 

 even the most remote corners, so that the 

 system of circulation of air, so to speak, must 

 necessarily be very perfect and complicated. 

 In the bee, moreover, the circulation of the 

 blood, which is very imperfect, has only the 

 task of distributing the nutritious substances 

 and of excreting the waste products. 



Let us now see how the air is carried into 

 all the corners of the bee's body, and also 

 how it is expelled. In the breast of the bee 

 there are three pairs of breathing-holes, and 

 in the abdomen six pairs, called stigmata, or 

 spiracles, through which the air passes dur- 

 ing inspiration and expiration. The air ex- 

 pelled is impoverished of oxygen but en- 

 riched with carbonic-acid gas. These stig- 

 mata are rather complicated organs, having 

 muscles which enable the bee to close and 

 open the holes voluntarily. Doubtless the 

 stigmata serve also in lieu of a larynx — that 

 is, as an instrument for producing certain 

 sounds. 



To every stigma is annexed a large bron- 

 chus, extending into the interior of tne body, 

 where it is divided into smaller branches, or 

 tracheas. This ramification or sub-division 

 continues constantly, so that at last the tra- 



