TY - JOUR T1 - Microscopical Observations on the Structure of the Spleen, and the Proboscis of Fleas. By Mr Anthony Van Leeuwenhoek, F. R. S. JF - Philosophical Transactions (1683-1775) VL - 25 SP - 2305 EP - 2312 PY - 1753/01/01/ UR - http://dx.doi.org/10.1098/rstl.1706.0024 M3 - doi:10.1098/rstl.1706.0024 AU - van Leeuwenhoek, A. ER -