VII.] ANIMALS AND PLANTS. 163 



what I thought some organisms visible in it were. I 

 looked and observed, in the first place, multitudes of 

 Bacteria moving about with their ordinary intermit- 

 tent spasmodic wriggles. As to the vegetable nature 

 of these there is now no doubt. Not only does the 

 close resemblance of the Bacteria to unquestionable 

 plants, such as the Oscillatorice, and lower forms of 

 Fungi, justify this conclusion, but the manufacturing 

 test settles the question at once. It is only needful 

 to add a minute drop of fluid containing Bacteria, to 

 water in which tartrate, phosphate, and sulphate of 

 ammonia are dissolved ; and, in a very short space of 

 time, the clear fluid becomes milky by reason of their 

 prodigious multiplication, which, of course, implies the 

 manufacture of living Bacterium-stuff out of these 

 merely saline matters. 



But other active organisms, very much larger than 

 the Bacteria, attaining in fact the comparatively 

 gigantic dimensions of 30 1 00 of an inch or more, in- 

 cessantly crossed the field of view. Each of these had 

 a body shaped like a pear, the small end being slightly 

 incurved and produced into a long curved filament, or 

 cilium, of extreme tenuity. Behind this, from the 

 concave side of the incurvation, proceeded another 

 long cilium, so delicate as to be discernible only by 

 the use of the highest powers and careful management 

 of the light. In the centre of the pear-shaped body a 

 clear round space could occasionally be discerned, but 

 not always ; and careful watching showed that this 

 clear vacuity appeared gradually, and then shut up 

 and disappeared suddenly, at regular intervals. Such 



