CRYSTAL LATTICE RESOLUTION 



27. Rehbinder, p., Disc. Faraday Soc, 18, 151 



(1954). 



28. HoRNE, R. W., Matuevic, E., Ottewill, R. 



H., AND Weymouth, J. W., Kolloid-Z., 161, 

 50 (1958). 



29. Ammann-Brass, H., Chimia, 10, 173 (1956). 



30. Perry, E. J., J. Colloid Sci., 14, 27 (1959). 



31. MiRNiK, M., Stromal, P., Wri.scher, M., 



and Tezak, B., Kolloid-Z., 160, 146 (1958). 



32. Reicke, W. D., "Proc. First Regional Euro- 



pean Conference on Electron Microscopy," 

 98, Stockholm, 1956. 



33. SuiTO, E. and Uyeda, N., "Proc. Interna- 



tional Conference on Electron Microscopy," 

 223, London, 1954. 



34. Heidenreich, R. D., Phys. Rev., 62, 291 



(1942). 



35. Mollenstedt, G., Optik, 10, 72 (1953). 



36. Rang, O., Z. Phys., 136, 465, 547 (1953). 



37. Ito, K. and Ito, T., J. Electronmicroscopy 



(Japan), 1, 18 (1953). 



38. HiRscH, P. B., HoRNE, R. W., and Whelan, 



M. J. Phil. Mag., 1, 677 (1956). 



39. Whelan, M. J., Hirsch, P. B., Hornb, R. W. 



AND BoLLMANN, W., Proc. Roy. Soc, A240, 

 524 (1957). 



40. Horne, R. W. and Ottewill, R. H., /. Phot. 



Sci., 6, 39 (1958). 



41. Horne, R. W. Ottewill, R. H., "Fourth 



International Conference on Electron Mi- 

 croscopy," Berlin, Springer Verlag, 1, 140 

 (1960). 



42. Bradley, D. E., Brit. J. Appl. Phys., 10, 198 



(1959). 



43. Anderson, N. G. and Dawson, I. M., Proc. 



Roy. Soc, A218, 255 (1953). 



44. Berriman, R. W. and Herz, R. H., Nature, 



180, 293 (1957). 



45. Hamilton, J. F., and Brady, L. E., /. Appl. 



Phys., 29, 994 (1958). 



46. Hamilton, J. F., Brady, L. E. and Hamm, 



F. A., /. Appl. Phys., 29, 800 (1958). 



47. Levenson, G. I. P. AND Tabor, J. H., Sci. 



and Indust. Phot., 23, 295 (1952). 



48. Klein, E., Mitt. Forsch. Agfa, 10 (1955). 



49. Hamm, F. A., and Comer, J. J., /. Appl. 



Phys., 24, 1495 (1953). 



50. Sawkill, J., Proc Roy. Soc, A229, 135 (1955). 



51. Goodman, J. F., Proc Roy. Soc, A247, 346 



(1958). 



52. Hamilton, J. F., Hamm, F. A., and Brady, 



L. E., J. Appl. Phijs., 27, 874 (1956). 



53. Hoerlin, H. and Hamm, F. A., J. Appl. Phys., 



24, 1514 (1953). 



54. von Ardenne, M., Z. Phys., 120, 397 (1943); 



Kolloid-Z., 108, 195 (1944). 



55. Preuss, L. E. and Watson, J. H. L., /. Appl. 



Phys., 21, 902 (1950). 



56. TuRKEvicH, J. AND HiLLiER, J., Atiol. Chcm., 



21, 475 (1949). 



R. H. Otteavill 



CRYSTAL LATTICE RESOLUTION 



The ultimate goal of electron micro.scopy 

 is, of course, the resolution of atoms in any 

 structure, and this possibility has been ana- 

 lyzed theoretically by several of the eminent 

 workers. If atoms or molecules are regularly 

 arranged in a crystal lattice there is a much 

 stronger chance of resolved image formation 

 than in the case of two isolated atoms be- 

 cause there are definite phase relationships 

 between electrons scattered from neighbor- 

 ing noncoherent atoms. The resolving power 

 of the best electron microscopes produced in 

 the world is limited first by diffraction error 

 and spherical error to about 2.8 A, and chro- 

 matic error and astigmatism increase this to 

 at least 7 A. At this value it should be possi- 

 ble to observe crystal lattices in crystals with 

 fairly large lattice parameters of the order 

 of 10 A or greater. 



Great success prior to 1956 in the investi- 

 gation of macromolecular crystals of viruses 

 and proteins by the replica technique had 

 been achieved by Wyckoff and associates at 

 the National Institutes of Health (3). The 

 surface of a needle-shaped crystal of the jack 

 bean protein concanavallin, with molecule 

 weight 42,000, among the smallest thus far 

 replicated, reveals a rectangular net of about 

 62 X 87 A of particles (30-40 A in diameter) 

 which are not in contact. The most likely 

 next step downward in dimensions would be 

 for crystals of organic molecules of inter- 

 mediate molecular weights, sufficiently thin 

 and properly oriented for direct transmis- 

 sion micrographs. 



Menter (1) was the first to produce elec- 

 tron micrographs of the lattice planes in 

 crystals. He was particularly fortunate in 

 his choice of metal phthalocyanins, especially 



145 



