Meir Yechiel Halevi Halstock (1852-11 March 1928) also known as the Ostrovtser Rebbe was a Hassidic rabbi who spent much of his life based in the city of Ostrowiec Świętokrzyski.
Halstock was born in Savin, near Kraków where his father and grandfather before him worked as bakers.
[2] Because of his youth the town requested that he get semicha from a number of specific rabbis including Josua Heschel Kuttner, who wrote "how can a fly with his wings cut off give testimony about an eagle that soars in the sky".
[4] By the end of his life many of his organs had shut down because of the years of fasting, and he was left bed ridden and constantly cold.
[1] Halstock used gematria (numerology based on the Hebrew alphabet) and mathematical formulas to explain passages in the Talmud.