142 : Colonial Organisms. [ February, 
reproduction. We venture to offer the hypothesis that the meri- 
stem, or generalized active tissue, is made up of such reproduc 
tive cells, each capable of asexual development, or of being cot 
verted, through the medium of the flower organs, into sexul 
germs. If this be correct, the meristem cells of plants represet! 
in their germinal powers the generalized tissue cells of the tie 
animals, and the wandering white corpuscles of the higher 
animals. : 
Abundant, however, as germinal cells may be in every partot 
very organism, yet only a limited number of them can develop 
since their growth acts to exhaust the strength and substance t 
the parent form. Only in the lower single-celled organisms 0 
we find instances in which. the whole body is converted p 
active germs, and the parent disappears in its offspring. In ae 
the higher animals and plants this only partially takes place, a 
the less so the higher the organism. " 
The development of the germ cells usually occurs only 
those points where favoring conditions most fully exist. In " 
ual reproduction these points are particularly limited in “a 
since the requisite meeting of germs from two organisms ~ ; 
take place through the aid of a special mechanism. j 
reproduction needs no such special mechanism, and may g 
in most regions of the body. Yet, as life advances in grade, a 
favoring conditions of asexual development will be apt t 
more abundantly in some regions of the body than in others, # 
tend to become confined to these regions by hereditary t i 
sion. In the higher plants these regions are usually i 
- axils, in which a degree of protection is afforded the bud, or pat : 
tially developed germ. But if a tree be closely trimmed, # i 
thus deprived of all its buds, new germs may develop # a 
point in the secondary meristem of the trunk or branches,“ 
new shoots appear, the product of germinal cells which 0 | 
would have lacked the opportunity to develop. oats 
In the development of the germs of the root fibers or shot : 
no such protection is requisite, and they may start me ‘ 
point in the cambium layer. They are evidently the prov he 
those meristem cells, which have been most successful 1% 
general effort to develop. : ; 
The reason that certain cells alone succeed in develope is 
of the great mass of cells that possess equal germinal pow” ; | 
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a 
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