NEW CONCEPTIONS IN SCIENCE 



The number of living units in a single microscopic liver- 

 cell would, on this computation, be above 64,000 millions. 

 The total number of atoms would be around 300,000,000 

 millions. The number, I think, is sufficient to account for 

 a tolerable amount of vital activity. With 300,000,000 

 million atoms of varying size and quality, grouped to- 

 gether in almost infinite variety into 64,000 million 

 molecules, one might do a good deal of explaining. 



Perhaps it will be worth while to offer another calcula- 

 tion of a little different sort. Living substance, proto- 

 plasm, is supposed by Biitschli and others to have a 

 honeycomb-like structure. Suppose that the figure of one 

 and three-quarter micro-microns for the living molecule 

 is somewhere around the reality, and that we use these 

 to build little compartments, as in a honeycomb. We will 

 make the walls of each compartment four molecules, or 

 7 nn thick; one might compare it to a brick wall, four 

 bricks, or around one foot, thick. The diameter of each 

 compartment we may suppose ten times that of the walls, 

 or, say, 70 fi/i, and filled with water, oxygen, food, sugar, 

 bile, waste products, poisons, mineral salts, and other 

 things, just as is the living liver-cell. This would make 

 each cell eighty per cent, or more water and other things, 

 ten or twenty per cent, protoplasm. In a single liver-cell 

 of one hundred cubic microns we should have a million 

 of these honeycomb-like compartments. Supposing that 

 each liver-cell contains as many distinct organs as the 

 human body, say twelve or fifteen, each of these separate 

 organs of the liver-cell might contain near a hundred thou- 

 sand chambers or compartments. Whatever may be the 

 actual number, it is certainly enormous. 



And the liver-cell is small. Beside it, the human germ- 

 cell is huge. The speck from which we spring is little 

 enough. It is practically invisible to the naked eye 

 only 0.2 of a millimetre in diameter. But that is 200 /A, or 

 nearly thirty times the diameter of a liver-cell. Its bulk is, 

 therefore, 27,000 times as great. In a single microscopic 



246 



