I; ANIMALCULA OF INFUSIONS. 13J 



ly about in the drop. The filament proceeds 

 from the poflerior part of the animal ; and al- 

 though its natural pofition is in a right line, it 

 often contracts fuddenly into a fpiral whofe volu- 

 tes approach fo near as to touch : in a moment 

 they recede ; the fpiral unfolds, and refumes the 

 ftraight line. While unfolding, or already ftretch- 

 ed, if a gentle motion is given to the drop, the 

 filament becomes a fpiral. If its extremity is 

 fixed, any contradlion towards the fpiral forces 

 the animalcule rapidly to the fixed point ; when 

 free, it approaches the animalcule. This it fre- 

 quently does, almofl periodically. It is of a 

 pearl colour, and of extreme ilendernefs, at 

 lead compared with the animalcule ; the length 

 equals it, and is fometimes more. The figure 

 refembles an onion or bulb : to the extremity is 

 attached the filament as the roots originate ; 

 thence it was named the bulh-ajinnakule ( i ). A 

 circular row of filaments proceed from around 

 a hollow, Thefe extremely flender fibrilli aire 

 in a conftant vibratory motion, which occafions 

 a whirlpool in the fluid, abforbing the fmalled 

 adjacent particles, and fometimes very minute 

 athimalcula. As the bodies gradually approach, 

 the motion becomes more rapid. Attending 

 I 2 carefully 



( I ) This 16 the Vorticslla Hians of MuUer. Animal- 

 tula Infuforia, p. 321. — T, 



