VOL. XIX.] PHILOSOPHICAL TRANSACTIONS. gQ 



Microscopical Observations of vast Numbers of Animalcules seen in IVater. By 

 John Harris, M. A. Rector of IVinchelsea, Sussex, and F. R. S. N" 220, p. 254. 



July the 7th, 1691, I examined a small drop of some rain-water which had 

 stood in a gallipot in my window for about 2 months. I took it with the head 

 of a small pin from the discoloured surface of the water, and observed in it 4 

 sorts of animals. In the clear part of the drop were 2 kinds, and both very 

 small. Some were of the figure of ants' eggs ; these were in continual and 

 swift motion ; and I find that this kind of oval figure is the most common to 

 the animalcules found in liquors. The other species, that were in the clear part 

 of the drop, were much more oblong ; about 3 times as long as broad ; these 

 were exceedingly numerous, but their motion was slow in comparison of the 

 former. 



In the thick part of the drop, for the water had contracted a thickish scum, 

 I found also 2 species of animals: as, a kind of eels, like those in vinegar, but 

 much smaller, and with their extremities sharper ; these would wriggle out into 

 the clear part, and then suddenly return back again, and hide in the thick and 

 muddy part of the drop, much like common eels in the water. I saw here 

 also an animal like a large maggot, which would contract itself up into a sphe- 

 rical figure, and then stretch itself out again ; the end of its tail appeared with 

 a forceps, like that of an ear-wig, and I could plainly see it open and shut its 

 mouth, from whence air-bubbles would frequently be discharged. Of these I 

 could number about 4 oj 5, and they seemed to be busy with their mouths, as 

 if in feeding. 



These 4 kinds of living creatures I found afterwards also in many other drops 

 of the same corrupted water, viz. in its film or scum, which was on the sur- 

 face ; for under that, in the lower parts of the water, I could never find any ani- 

 mals at all, unless when the water was disturbed, and the surface shaken down 

 into, and mingled with the lower pnrts. 



April 27th, 1696. With a much better microscope I examined some rain- 

 water, which had stood uncovered a pretty while, but had not contracted any 

 such thick and discoloured scum as that before mentioned had. In this, where 

 it was clear, I could not find any animals at all ; but a little thin white scum, 

 which like grease began to appear on the surface, I found to be a congeries 

 of exceedingly small animalcules of diflrerent shapes and sizes, much like those 

 produced by steeping barley in water. 



At the same time I looked on a small drop of the green surface of some 

 puddle water : this I found to be altogether composed of animils of several 

 shapes and magnitudes} but the most remarkable were those which I found 



VOL. IV. N 



