He began studying Masha and Dasha within days of their birth. He had put out an alert to all maternity hospitals in the USSR to be informed if any conjoined twins were born. Conjoined twins who shared a blood system but had separate nervous systems were ideal objects for research. The Soviet physiologist Pyotr Anokhin was studying the separate roles of the nervous system and the blood system on the body's ability to adjust to conditions such as prolonged sleep deprivation, extreme hunger, and extreme temperature change. Their mother was told that her daughters had died soon after their birth.
They were removed from their mother's custody at birth to be studied by Soviet physiologists. Maria and Daria ('Masha and Dasha') Krivoshlyapova (Мария и Дарья Кривошляповы 3 January 1950 – 17 April 2003) were Ischiopagus tripus conjoined twins from Russia.
