626 



Microscopical Essays. 



It may be proper to obferve, firft., that Mr. Muller's wheel 

 animal differs in fome refpecls from that of Mr. Baker's ; fir ft, by 

 the rotatory organs on the back, which flretch out like ears ; 

 fecondly, the two little fplendid fubftances within the body ; 

 and thirdly, the two black points near the top of the head, which 

 are probably the creature's eyes. 



This little animal is found in rain water that has flood for fome 

 days in leaden gutters, or in the hollows of lead on the tops of 

 houfes, or in the flime and fediment left in rain water ; they are 

 fometimes to be found alfo in ditches and amongft duck-weed. 



It has been called the wheel animal becaufe it is furnimed with 

 a pair of inftruments, which in figure and motion refemble 

 wheels. It appears only as a living creature when in water, and 

 yet it may be kept for many months out of water, and in a ftate 

 as dry as duff, without lofing the principle of life. When dry, 

 it is of a globular form, about the fize of a grain of fand, and 

 without any apparent figns of life. If it be put into the water, in 

 the fpace of half an hour a languid motion begins, the globule 

 turns itfelf about, lengthens itfelf by flow degrees, becomes very 

 lively, and in a little time protrudes it's wheels, and fwims about 

 in fearch of food ; or elfe, fixing itfelf by it's tail, brings the food 

 to it by the motion induced on the water by it's rotatory organs. 



If the water that is found ftanding in gutters of lead, or the 

 fediment it has left behind, has any thing of a red colour, you 

 may be almoft fure of finding thefe animalcula therein. In fum- 

 rner, when all the water is dried away, if the duff appears red, or 

 of a dark brown, and is put into water, you will feldom fail to 



difcover, 



