The problem, 51. — Analysis of Statistics of Income data, 52. — Qualifications, 53. — Analysis of data for individual corporations, 53. — Discriminatory effects increase in proportion to tax-rate, 58. — Cyclical effects of the excess profits tax, 58. — Incidence of the undistributed profits tax, 60. — Probable effects on revenue of loss carry forward provisions, 60. — Analysis of data for forty corporations, 65. — Effectiveness of such provisions, 68. — British practice, 69. — Conclusion, 71.