THE ORIGIN OF LIFE 



various evolutionary forms of living matter — from the 

 simplest moneron (chroococcus) to the plain nucleated 

 cell, from this to the highly organized cell of the radio- 

 laria and infusoria, from the simjile ovum to the most 

 elaborate tissue-stnicture in tlic higher ])lants and 

 animals, from the am])hioxus to man — come in an order 

 of succession. There are only two ways of explaining 

 this fact: either the simplest living organisms, the 

 chromacea and bacteria, the jjalmella and amoeba?, have 

 remained unchanged or made very little advance in 

 organization since the beginning of life — more than a 

 hundred million years; or else the phylogenetic process 

 of their transformation has been frequently repeated in 

 the course of this period, and is being repeated to-day. 

 Even if the latter were the case, we should hardly be in 

 a position to learn it by direct observation. 



Assuming that the simplest organisms are still fonned 

 by abiogenesis, the direct observation of the process 

 would probably be impossible, or at least extremely 

 difficult, for the following reasons: i. The earliest and 

 simplest organisms are most probably globular particles 

 of plasm, without any visible structure, like the simplest 

 living chromacea {chroococcus). 2. These plasmodom- 

 ous monera cannot be distinguished from the chromo- 

 plasts (chlorophyll-granules), which live inside plant- 

 cells, and may continue after the death of the cells 

 to multiply independently by cleavage. 3. We must 

 admit with Nageli that the original size of these pro- 

 bionta (in spite of the relatively colossal size of their 

 molecules) is very small — much too small to come within 

 the range of the best microscope. 4. In the same way 

 the primitive metabolism and the slow, simple growth of 

 these monera would not come within direct observation. 

 5. As a matter of fact, we do often find in stagnant 

 water, and in the sea, tiny granules which consist, or 

 seem to consist, of plasm. We usually regard them as 



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