II. INTRODUCTION. 7 



as those whose cj'clical development is more evident; and it remains for the sup- 

 porters of the doctrine to present one single direct observation, before even its 

 probability can be asserted. 



To learn fully the nature, origin, and most favorable conditions of entozoic and 

 entophytic life, we must commence our investigations with a clear view of the 

 character and conditions of life in general. 



An attentive study of geology proves that there was a time when no living 

 bodies existed upon the earth. 



The oblately spheroidal form of the earth, and the physical constitution of its 

 periphery, indicate that it was once in a molten state. 



A progressively increasing temperature in descending into the interior of the 

 earth beyond the solar intluence, with the phenomena of volcanoes, earthquakes, 

 hot springs, etc., are strong evidences that the central mass of this planet yet 

 preserves its early igneous condition. 



The period which elapsed was incalculably great before the earth-crust upon its 

 liquid nucleus had sufficiently cooled by the radiation of its heat for living Ijeings 

 to become capable of existing upon its surface. Not until the temperature had 

 been reduced below the boiling point of water (212° F.), could life have originated, 

 for water in its liquid condition is neccssarj' to the simplest phenomenon of life. 

 It is even highly pi'obable that no living thing appeared upon the earth's surfoce 

 until its temperature had fallen below 1G5°. This ordinarily is the highest point 

 at which albumen coagulates,^ a substance in the liquid form, probably existent in 

 all living beings, and essential to the performance of the simplest vital phenomenon. 



Living beings, characterized by a peculiar structure and series of phenomena, 

 appeared upon earth at a definite though very remote period. 



Composed of the same ultimate elements which constitute the earth, they ori- 

 ginated in the pre-existing materials of their structure. 



Living beings originate in a formless liquid matter. The first step in organiza- 

 tion is the appearance of a solid particle. An aggregation of organic particles con- 

 stitutes the spherical, vesicular, nucleolated, nucleated body, the organic cellj the 

 type of the physical structure or organization of living beings. 



The phenomena which characterize the living being are : 1. Origin, or birth; 2, 

 nutrition and assimilation; 3, exuration ;^ 4, development and growth; 5, repro- 

 duction ; 6, death. These, in the aggregate, constitute life. 



The origin or birth of a living being, is the appearance of its first particle, 

 whether directly from inorganic nature or from a parent. There is a birth to 

 every organic cell. 



• Vegetable albumen coagulates from 140° to IGO" F. ; animal albumon, froiu 145° to 10.5°. — Turner's 

 Chemistry, American edition, pp. 740, 744. 



Albumen in the liquid state "on being heated to 140° begins to give indications of coagulating : if the 

 solution is very dilute, the temperature may be raised to 1(!.j° with the occurrence of this change ; and 

 when present in very small quantity, the albumen may not separate till the fluid boils, or even until the 

 ebullition has been prolonged for a short time." — Simon's Chcmhtri/ of Man, Am. ed. 184G, p. 24. 



^ Kniro, I consume. 



