152 LIFE: ITS NATURE AND ORIGIN 



is indicated by the simple union of two oppositely charged ends of 

 polar molecules. It also accords with the view of Alexander and 

 Bridges that the cell is a "box-within-box" structure. 



It must be remembered that every free unit or surface having 

 unsatisfied residual electronic fields tends to draw to itself units of 

 opposite charge pattern or areas of opposite electronic contour, 

 even if several molecules are needed to complete the opposite 

 mosaic. Crystallization proceeds this way with the elimination of 

 stranger molecules; but it can also happen that there are "lacunae" 

 or adsorbed "impurities," so that the film or layer, especially if a 

 thick one, may not ideally perfect. 



To go to one extreme, when atomic nuclei are deprived of one or 

 more electrons, they strive to replace them or at least to share 

 electrons with other nuclei, as in covalent compounds. At higher 

 structural levels the residual forces become more feeble and in- 

 definite, but nevertheless effective. Sir W. B. Hardy 27 showed 

 how exceedingly difficult it is to secure a really clean surface, and 

 we can understand how nascent atoms, molecules, and areas may 

 be highly and specifically active, especially in the loci where they 

 are liberated or formed. Lord Rayleigh pointed out that a film 

 of "grease" adsorbed from the atmosphere exists on most exposed 

 surfaces, and to this film all kinds of small particles of "dirt" 

 may adhere. In South Africa when a slurry of diamond-bearing 

 clay flows down a trough lined with tallow, the grease selectively 

 fastens most of the diamonds. Microscopic examination of "house- 

 moss" (or 'cobwebs") — that fluffy horror of meticulous house- 

 keepers — shows it to consist mainly of tiny textile fibers (cotton, 

 wool, etc.) with adsorbed "grease" and mineral particles. By 

 twisting "house-moss" between the fingers, it can be "spun" into a 

 weak but coherent "thread." And millions of letters daily travel 

 in the mails with their postage stamps securely attached, though 

 not even a strict stoichiometrist among chemists would suggest that 

 the "compound" should be called stampate of envelope, or en- 

 velopate of stamp. 



REFERENCES 



1 Alexander, Science (1936), 83, 230. 

 2/. Exp. Med., 69, 119 (1939). 

 3 "Colloid Chemistry," Vol. V, pp. 564-6. 

 4 /. Am. Chem. Soc, (1939). 



5 "The Chemistry of Antigens and Antibodies," 2nd ed., Brit. Med. Res. Council, 

 London, 1939. 



6 /. Exptl. Med (1928) 47, 757. 



