THE METAPHASE ARREST TECHNIQUE.

Abstract
The accuracy and precision of the stathmokinetic experiment for the determination of cell birth rate are discussed from practical and theoretical viewpoints. Topics covered include the determination of the optimal dosage of the metaphase arresting agent, the times at which observations should be taken and which cells should be counted, the correct method of estimating cell birth rate and the dependence of any derived estimate of the turnover on the age distribution of cycling cells. Failure to consider any of these points can lead to considerable inaccuracy. It is further shown that the stathmokinetic method is a rather imprecise one for measuring the turnover time and the duration of mitosis. Data are presented comparing the results of using this technique with those obtained from autoradiographic studies.