14 Life and Immortahty. 
be very necessary, and that is that the living body should be 
composed of a certain material. This material, which forms 
the essential and fundamental parts of everything living, 
whether vegetable or animal, is technically called proto- 
plasm. Other substances than it are often found in living 
bodies, but it is in protoplasm only that vitality appears to 
be inherent. 
But whether it is the same in plants as in animals is a 
matter of opinion. One thing, however, seems reasonably 
certain, and that is that it is the medium or vehicle 
through which vital force is made manifest. Used in its 
general sense, protoplasm is chemically related in its 
nature to albumen, and generally has the character of a 
jelly-like, semi-fluid, transparent material, which, in itself, 
exhibits no definiteness of structure. When heated to a 
certain temperature it coagulates, just as the white of an 
egg does when boiled. Living protoplasm has the power of 
movement, of increasing in size or of maintaining its exist- 
ence by the assimilation of fresh and foreign materials, and 
of detaching portions of itself which may subsequently 
develop into fresh masses. Though protoplasm be present 
in the ova of animals and the seeds of plants, yet there is no 
external and visible manifestation of life. There is in them 
what is called a dormant vitality, which may remain for a 
long time unchanged, until altered external circumstances 
cause the organism to pass into a state of active life. 
Generally, certain external conditions must be present 
before any external vital phenomena can be manifested. The 
presence of atmospheric air, or rather of free oxygen, is in 
an ordinary way essential to active life. Life, that is its 
higher manifestations, is only possible between certain 
ranges of temperature, varying from near the freezing 
point to about 120° Fahrenheit. As water is a necessary 
constituent of protoplasm in its living state, so it becomes an 
absolutely essential requisite to the carrying on of vital 
processes of all kinds, for the mere drying of an animal or 
