Mechanical preparation of cells for chromosome studies

A machine, performing hypotonic treatment and fixation of blood samples for chromosome analysis under standard conditions, is described. The machine has now handled specimens from 4,100 persons. 12 tubes are shaken at a rate of approximately 2,800/min, and simultaneously solutions for hypotonic treatment and fixation are added during 30-45 sec from a distribution chamber. The apparatus produces long, slender chromosomes suitable for staining by modern techniques which yield banded chromosomes.