Volumes 18, 19, and 20 of Alle de Brieven / Collected Letters became available at the end of 2024, completing the series begun in 1939. Download for free.

Master list (pdf) of all 602 L-numbers, their Leeuwenhoek number, and their Collected Letters number

Letter 33 Figure 1:
A glass filled with rain-water.
Een glas gevold met regen water.

Letter 33 Figure 2:
The junction of some blood-vessels.
De vereenige van eenige bloete vaaten.

Letter 33 Figure 3:
Cockchafers during copulation.
De kevers, soo als het versamelt was.

Letter 33 Figure 4:
Dragonflies, sticking together.
Jufferken, soo als deselve aen malkanderen.

Letter 33 Figure 5:
Dead little animal in dragonfly.
Doot dierken in de jufferken.

Letter 33 Figure 6:
Common fly.
Gemene vlieg.

Letter 33 Figure 7:
Veins in the windpipe of the flea.
Aderen in de gorgel van de vloij.

Letter 33 Figure 8:
Sphere or globe to show proportion.
Lighamelijke figuer of kloot om proportie te tonen.