INFUSORIA. 407 



quarter of a circle, whereby a *' feathering movement M is 

 effected, and a current in one direction constantly pro- 

 duced. In the higher animals, the action of the cilia can 

 oaly be observed a very short time after death. In a polypus 

 of the nose, when situated at the upper and back part of 

 the Schueiderian membrane, the cilia may be beautifully 

 seen in rapid action some few hours after its removal ; but 

 hi the respiratory and other tracts, where ciliated epi- 

 thelium is found, it would be almost impossible ever to 

 see it in action, unless the body were opened immediately 

 after death. In some animals it may be seen in the in- 

 terior of the kidney, as first made known by Professor 

 Bowman in the expanding extremity of the small tube 

 surrounding the network of blood-vessels forming the so- 

 called Malpighian body. In order to exhibit the ciliary 

 action, the kidney should have a very thin slice cut from 

 it; and this is to be moistened with the serum of the 

 blood of the same animal. The vascular and secreting 

 portions of the organ may then be seen with a power of 

 250 diameters, and also the cilia in the expanded extremity 

 of each tube, as it passes over to surround the vessels; the 

 epithelium of the tubes themselves is of the spheroidal or 

 glandular character. 



The infusorial and invisible atoms of life have various 

 periods allotted to them for the enjoyments of existence ; 

 some accomplish their destiny in a few hours, others in a 

 few weeks. The watchful devotee in this branch of science 

 has traced an animalcule through a course of existence 

 extending to the old age of twenty-three days. The vital 

 spark flies instantaneously in general ; but in those of a 

 higher organisation there is a spasmodic convulsion, as if the 

 delicate and intricate machinery rendered life so exquisite, 

 that the parting with the " heavenly flame " \vas reluctant 

 and painful. The most surprising circumstance attendant 

 on the nature of some of the Infusoria is that of apparent 

 death. When the water or mud in which they have sported 

 in the fulness of buoyant health becomes dried up, they lie 

 an inanimate speck of matter; but after months, nay, years, 

 a drop of water being applied, their bodies will be resusci- 

 tated, and in a short time their frames become active with 

 life. Leeuweuhoek kept some in a hard and dry condition. 



