58 HUMBLE CREATURES. 



on the ventral side, opposite the dorsal vessel, this is 

 by no means established ; and, on the other hand, it 

 is certain that a considerable quantity of the sangui- 

 neous fluid finds its way into the cavities of the body 

 {lacunce), and there bathes the intestines. 



This statement may perhaps cause you some sur- 

 prise, for you know, no doubt, that in the higher 

 animals an escape of blood internally, from the regu- 

 lar channels in which it is confined, would lead to 

 serious, if not fatal results ; and, moreover, the in- 

 quiries are at once suggested, " What becomes of the 

 blood after it has entered the cavities of the body? 

 and how is it that the supply is not exhausted?" 



An examination of the " dorsal vessel" shows that 

 it is not only furnished with valves that unite its 

 chambers, but also with another set, which are placed 

 at the side of the tube, and communicate with the 

 cavities of the body in such a manner as to admit of 

 the ingress, but not the egress of fluid. The blood 

 then, after having bathed the vital organs of the 

 body, accumulates around the dorsal vessel, into 

 which it is admitted by this second set of valves, and 

 again propelled forwards into the thorax. Moreover, 

 this wonderful force-pump (the dorsal vessel), with its 

 chambers and valves, gives out several fine branching 

 arteries, some of which are also said to terminate in 

 the cavities of the body*. 



* The circulation of the blood in insects may be observed in 

 some of the smaller Diptera, such as gnats, &c., where the ex- 

 ternal envelope is semitransparent, more easily than in the Bee. 



