354 Tke Microscope. 



ceed latterally, which subdivide themselves lo infinity. The subdi- 

 visions of each of tlie branches are joined at their extremities, 

 thereby forming a perfect connexion between the whole. The 

 blood proceeds from the main conduit by each alternate branch, 

 and after passins; through the various subdivisions of one branch, 

 enters those of the next, on each side of it, by which it returns into 

 the main conduit, and this process is repeated, until the mind is 

 bewildered in its attempts to trace its course in all its minute ram- 

 ifications. 



In this description the usual term of arteries and veins have 

 been avoided, as, in this animal, the distinction seems to be lost 

 in consequence of the blood appearing to issue from, and return 

 into the main conduit both in its salient and returning part, al- 

 though it is probable that the returning main conduit is really a 

 vein, receiving the returning branches, or veins, which must, 

 in that case, pass either above or below, and not into the salient 

 part of the main conduit or artery. As the substance in 

 which these main conduits are inserted is much more opaque than 

 the rest of the tail, the phenomenon cannot be so well observed, 

 and it is, in consequence, diflicult to arrive at a safe conclusion; 

 however, enough is to be perceived to excite the wonder and ad- 

 miration of every beholder. 



The Blood. Upon submitting the blood to the microscope, 

 it is immediately perceived to consist of globules suspended in a 

 white transparent serum. A remarkable fact will strike every 

 observer, viz. there will be seen a continual motion of the glob- 

 ules, as if they were acted upon by some unknown agency. This 

 motion appears completely vibratory, like a balance which has 

 received an impulse ; it is difficult to account for this phenomenon, 

 but the following hypothesis is hazarded. This seeming tendency 

 to motion in the globules, may be a material assistance to the im- 

 pulse given by the heart, whose mere mechanical force, however 

 great, appears hardly sufficient to propel the globules through 

 such inconceivably minute ramifications, through which we know 

 it does pass, previous to reaching the organ of circulation by the 

 larger veins. 



Place a small drop of water upon a slip of glass, into which in- 

 troduce a drop of warm blood, by which means the globules will 

 be separated, and become distinctly visible; use that power 

 which will most enlarge them without taking away from their dis- 

 tinctness. 



Pllsation of the Heart. This wonderful phenomenon may 

 be seen distinctly in several small insects; in a bee it is observa- 

 ble near the neck, but the best insect to view it in, owing to its 

 transparency, is the water flea. 



