In the United States v. Pelzer case of 1940, the Supreme Court ruled on a matter concerning federal income tax law. The respondent, William H. Pelzer, was an Alabama resident who had received dividends from a corporation in which he held stock and claimed these dividends as non-taxable on his federal income tax return for 1936 under Section 115(f) of the Revenue Act of 1936. However, this claim was rejected by the Commissioner of Internal Revenue and upheld by both lower courts before reaching the Supreme Court. The key issue at hand was whether or not certain distributions made to shareholders could be considered as returns on capital investment (and thus non-taxable), rather than taxable dividend income. The court ultimately decided that such distributions were indeed taxable dividends because they came out of earnings and profits accumulated after February 28th, 1913 - even if those earnings were derived from sales above asset cost. This decision reinforced that all corporate profit distributions are presumed to be taxable unless proven otherwise by taxpayers claiming exemptions under specific provisions like Section 115(f). It also clarified how "earnings and profits" should be calculated for purposes of determining what constitutes a dividend.

The United States v. Pelzer case does not appear to exist in the U.S. Supreme Court records for 1940 or any other year, making it impossible to provide a summary of the dissenting opinion for this case. It's possible that there may be some confusion regarding the name or date of the case in question. Please verify these details and try again.