140 THE MICROSCOPE. 



diately after death. In some animals it may be seen in the interior of 

 the kidney, as was first discovered by Professor Bowman in the ex- 

 panding 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. 



These 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 ma- 

 chinery rendered life so exquisite, that the parting with the " heavenly 

 flame" was 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 ful- 

 ness of buoyant health becomes dried up, they lie in an inanimate speck 

 of matter ; but after months, nay years, a drop of water being applied, 

 their bodies will be resuscitated, and in a short time their frames be 

 active with life. Leeuwenhceck kept some in a hard and dry condition, 

 and restored them to life after a sleep of death of twenty-one months. 

 Professor Owen saw an animalcule that had been entombed in a grave 

 of dry sand four years reborn to all the activity of life. Spallanzani 

 tried the experiment of alternate life and death, and accomplished it in 

 some instances on the same object fiftem, times ; after which nature 

 was exhausted, and refused further aid in this miraculous care of those 

 minute objects of her wonderful works. 



The infusorial animalcules vary in their capabilities of the endur- 

 ance of heat and cold ; some of them retaining life in water 200° Fah., 

 while others expire from the heat of a warm room. Many die when 

 the mercury is as low as 80° Fah., while others survive. They have 

 been found embedded in ice at the arctic regions, surrounded by a little 

 water, which Ehrenberg supposes is not frozen from the natural heat 

 of their bodies. Air is as necessary to their existence as it is to supe- 

 rior animals ; for if placed in a tightly-corked bottle in water, where 



