NATURE OF LIVING BODIES. 5 



yet they all show, in some measure, the existence of the same 

 power. And in the most imperfect species, where there is 

 no other evidence, this power is evinced by the fact, that the 

 individual freezes with greater difficulty before than after 

 death, other circumstances being equal.* 



Another illustration of the same principle is derived from 

 the change which takes place in the body after death. With 

 this change we are familiar. No sooner has it taken place, 

 than the heat and moisture of the external air commence the 

 work of destruction. The skin is discolored ; it becomes 

 green and livid ; the eyes sink in their sockets ; the flesh be- 

 comes soft and putrid ; it falls from the bones, and is con- 

 verted partly into foetid exhalations, and turns partly into dust. 

 Even the bones finally yield, and lose their form and consist- 

 ency. Now, why should this happen more readily after than 

 before death? The composition of the body is the same, arid 

 it is exposed to the same moisture and heat. It happens be- 

 cause the life has departed which gave to the body a power 

 of resisting the operation of these causes. 



This suggests to us, in the fourth place, another distinction 

 of living substances, viz. that they all terminate their exist- 

 ence in death. By this event, the materials which entered 

 into their composition are deprived of the bond which held 

 them together and gave to them their peculiar form, viz. the 

 principle of life. They therefore separate, and retain only 

 those properties which they possessed before becoming parts 

 of a living system. Dust returns to dust, earth to earth. It 

 is true, that some of the parts of living bodies, both animals 

 and vegetabfes, do not very readily undergo the process of 

 decay. The bones, teeth, shells, and horns of animals ; the 

 trunks, branches, and roots of trees, retain, for an almost in- 



* In quadrupeds and birds, the animal heat is generally greater than that of the 

 surrounding atmosphere, whilst in animals of the inferior classes, it is seldom very 

 different from that of the objects around them. The former are called warm-blooded, 

 and the latter cold-blooded. In the former, the temperature is capable of but 

 slight variation from external causes; in the latter, its range is pretty extensive, 

 mid it varies a great number of degrees. The temperature of a man plunged into 

 cold salt water at 44, has been known to sink to 83, and when exposed to a heated 

 atmosphere," to rise to 100 ; in other warm-blooded animals similar varieties 

 have been observed. But the temperature of the viper, a cold-blooded animal, when 

 exposed to a heat of 108, rises to 9-2, and when exposed to a cold of 10, sinks to 

 about the freezing point of water, showing at once an extensive range of tempera- 

 ture within which the functions can go on, and at the same time a decided power 

 of resistance against any further alteration. 



Eggs possess an analogous power. A new-laid egg, and one which has been fro- 

 zen and thawed, being exposed in a freezing mixture together, the former will b 

 borne minutes longer in freezing than the latter. This has been ascertained by ex- 

 periment. The same is true of the lower orders of animals and vegetables. 



