Plate, two cross-sections of the corpora cavernosa by Franz Bauer Plate XVIII showing two cross-sections of the corpora cavernosa, magnified four times in diameter. Subject: Anatomy Published in Philosophical Transactions as 'Observations on the human urethra, showing its internal structure, as it appeared in the microscope of F. Bauer, Esq'. Read 1 June 1820. [1820]