10 



a smaller splierical body, which existed, but was more or less 

 hidden, in the living corpuscle, and is called its nucleics. Cor- 

 puscles of essentially similar structure are to be found in the 

 skin, in the lining of the mouth, and scattered through the whole 

 framework of the body, ^^'ay, more; in the earliest condition 

 of the human organism, in that state in which it has just become 

 distinguishable from the Qg^ in which it arises, it is nothing but 

 an aggregation of such corpuscles, and every organ of the body 

 -was, once, no more than such an aggregation. Thus a nucleated ( 

 .mass of protoplasm turns out to be what may be termed the . 

 structural unit of the human body. As a matter of fact, the 

 body, in its earliest state, is a mere multiple of such units ; and, 

 in its perfect condition, it is a multiple of such units, variously 

 modified. But does the formula which expresses the essential 

 structural character of the highest animal cover all the rest, as 

 the statement of its powers and faculties covered that of all 

 others ? Very nearly. Beast and fowl, reptile and fish, mollusk, 

 worm, and polype, ai-e all composed of structui-al units of the 

 same character, namely, masses of protoplasm with a nucleus. 

 There are sundry ver}^ low animals, each of which, structurally^ 

 is a mere colorless blood-corpuscle, leading an independent life. 

 But, at the very bottom of the animal scale, even this simplicity 

 becomes simplified, and all the phenomena of life are manifested 

 by a particle of protoplasm without a nucleus. Xor are such 

 organisms insignificant by reason of their want of complexity 

 It is a fair question whether the protoplasm of those simplest 

 forms of life, which people an immense extent of the bottom of 

 the sea, would not outweigh that of all the higher living beings 

 which inhabit the land put together. .Vnd in ancient times, no 

 less than at the present day, such living beings as these have 

 been the greatest of rock builders. 



What has been said of the animal world is no less true of 

 plants. Imbedded in the protoplasm at the broad, or attached, 

 end of the nettle hair, there lies a spheroidal nucleus. Careful 

 examination further proves that the whole substance of the nettle 

 is made up of a repetition of such masses of nucleated proto- 

 plasm, each contained in a wooden case, which is modified in 

 form, sometimes into a woody fibre, somethnes into a duct or 

 spiral vessel, sometimes into a i:>ollen grain, or an ovule. Traced 

 back to its earliest state, the nettle arises as the man does, in a 

 particle of nucleated protoplasm. And in the lowest plants, as in 



