24 THE PHYSICAL BASIS OF LIFE 



growth and crowding together finally produce the emul- 

 sion-like structure. In the middle stages of this process 

 the protoplasm gives an interesting picture (Fig. 13). 

 When viewed under a relatively low magnification, e.g., 

 300-500 diameters, only the larger bodies are seen ; but as, 

 step by step, we increase the magnification, step by step 

 we see smaller and smaller bodies coming into view, at 

 every stage graduating down to the limit of vision. This 

 remains true even with the highest available powers. The 

 microscopical picture offered by such protoplasm is thus 

 somewhat like the telescopic picture of the sky. At each 

 step in the improvement of the telescope new and fainter 

 stars have come into view. At each step the astronomer 

 has felt sure that still more powerful telescopes would 

 bring into view stars hitherto unseen. The cytologist is 

 equally sure that if the present limits of direct micro- 

 scopical vision could be extended we should see dispersed 

 bodies still more minute ; and the invention of the ultra- 

 microscope has in fact made us directly aware of the ex- 

 istence of suspended protoj)lasniic particles too small to 

 be seen directly by the ordinary microscope, but made evi- 

 dent bv their lialos when viewed in powerful reflected 



light. " 



It is nearly certain that in these eggs some of the scat- 

 tered bodies are derived as such from the mother-cell, in 

 the form of pre-existing chondriosomes or Golgi-bodies. 

 Aside from siich bodies, however, there are manv smaller 

 ones that take origin in those most mimite granules that 

 lie near the limit of' microscopical vision and seem 

 to arise de novo in the hyaloplasm. But manifestly it is 

 quite illogical to affirm an origin de novo of any formed 

 body because it first becomes visible at a particular en- 

 largement, even the greatest at our present conm^^iand. 

 Here, clearly, is an enormous gap in our knowledge. The 



