FIG. 6. Series of phase contrast photographs of a chick fibroblast in a culture treated with
beryllium ions. Time sequence a - b - d - c - e .
(a) Metaphase begins normally; (b) 2 h 40 min later, (b-d) Successive aspects taken within
a few minutes, (c) A nuclear area, not yet limited, with reformed nucleoli is visible, (e) The
cell has flattened out again, is alive and in good condition, (a-d) x 1125. (e) x 805.
(Chevremont and Firket, 1952a.)