Relation of Inorganic to Organic Bodies 55 



in their extreme adaptability have undergone slow subsequent 

 modifications to suit changing terrestrial en^dronal conditions. 



It must be admitted that, between even the simplest of 

 these and the most perfectly adjusted colloid substances or 

 mixtures that we know, the difference is great. But this 

 difference we can only regard as one of degree, for nearly all 

 of the physico-chemical and physiological peculiarities are 

 shared in common, though to varying extent in different 

 bodies. 



The Schizomycetes, or in general language Bacteria, show 

 many resemblances to the last group, but are devoid of blue- 

 green pigment. As already indicated (p. 40) good reasons can 

 be adduced for considering that they may have evolved along 

 at least two or three separate lines by distinct methods of 

 energy utilization. In contrast to the fairly large size of schizo- 

 jjhyceous species, the present are nearly all small, though 

 Hillhousia mirabilis, first described in 1909 by West and Grif- 

 fiths (Proc. Roy. Soc. 81: 398. 1909), almost rivals the algoid 

 species. Much can be said in favor of the \dew that the more 

 primitive types of animal branched off from them, and such 

 is accepted as likely in this work. Most animal forms, how- 

 ever, have assumed a more active and rapidly multiplying 

 mode of life than is seen in the former group, and so the forma- 

 tion of mucilaginous walls or masses of colloid jelly is rarer. 

 But further, except for the purple pigmented cylinder of the 

 purple bacteria, each cell in the Schizomycetes is devoid of 

 the chromatophore of the Scliizophyceae. The protoplasm is 

 either dense, finely granular, and fills the cell cavity, or often 

 one or more central vacuoles may arise. There has been much 

 discussion as to the presence of a nucleus. Often the methods 

 of preparing and staining preparations of the species seem 

 accountable for what looks like a nucleus. Most observers 

 are agreed, that here as in the former group no nucleus exists, 

 but that evolving chromatin granules or chromidia may rep- 

 resent a rudimentary nuclear substance. Vejdovsky, however, 

 considers that he has satisfactorily demonstrated its existence 

 in some species. 



