THE DESCENT OF PROTOPLASM 185 



question the fact that Monera are really structure- 

 less, and, as was suggested in the previous chapter, 

 it seems probable that there is a series of nuclei 

 one within the other, even though our optical 

 arrangements do not enable us to follow them. As 

 in the case of the Monera, the structure may be 

 too fine to admit of staining by ordinary means. 



In discussing the descent of living matter this 

 point is not of so much importance. We regard 

 such matter as the direct descendant, including 

 the Monera, of probably much simpler types. 

 Just as successive variations in each genera- 

 tion have been sufficient to provide the most 

 varied types and amongst these a few which have 

 been suitable to their surroundings : so also there 

 may have been others which, instead of adding to 

 their complexity by successive variations, have 

 become simpler and simpler ; and even amongst 

 these there could have been some ' types which, 

 whilst being sufficiently adapted to their environ- 

 ment, and by possessing the power of reproduction 

 in an indefinite series, have also been able to survive. 

 It seems not unlikely that the Monera belong to 

 this type, and that, simple as they are, they difier, 

 if not as largely at any rate largely, from the 

 original types as many of the higher organisms 

 themselves. There is no need to enter here 

 into the evidence for the development of the 

 various species, as for instance from palaeontology, 

 comparative anatomy, and embryology. We are 

 more chiefly concerned with the evolution of that 



