An Introduction to a Biology 



to make a cart with. It was not until man had 

 deputed the labour of haulage to his beast of burden 

 that the wheel became an important factor in human 

 economy. For the chariot preceded the wheel- 

 barrow. It was not, therefore, till the man had 

 detached from himself both the matter of which he 

 makes his organs and the power which sets them in 

 motion that the wheel could begin to show itself 

 above the horizon of practicability. 



But the early naturalists evidently did not think 

 that the growth of a wheel presented any difficulties 

 to even the lowliest organisms. Certain animalcules 

 possess a circlet consisting of a great many vibratile 

 cilia (delicate whips of protoplasm) ; and the waves 

 passing rapidly round this circlet, like waves on a 

 field of corn, but produced not, as in the cornfield, 

 by an external agency, the wind, but by the volun- 

 tary supination in extremely rapid succession of 

 the cilia composing the circlet, make an excellent 

 imitation of a revolving wheel. This is the descrip- 

 tion of one of these animalcules by Leeuwenhoek^ 

 in 1702 : " Out of the same sheath appear'd a little 

 Creature, the fore-part of whose Body was roundish, 

 and presently from the same Eotundity proceeded 2 

 little Wheels that had a swift Gyration. The Limner 

 observing the Eotation of the Wheels, which always 

 ran one and the same way, could not be satisfied 

 with the sight, adding, 0, that he could always 

 see such a wonderful kind of a motion." It is a 

 tribute to the early naturalists who took this imita- 

 tion for the reality and dubbed these animalcules 



^ " Pliilosopliical Transactions of th« Royal Society," Vol. XXIII. 

 No. 283. 



69 



