Fig. 3.1 — Photomicrographs from embryo of grasshopper, sectioned 13 microns, stained 

 with iron hematoxylin. A. Untreated cell at metaphase, spindle fibers difFerentiated. B. 

 Cell treated, 25x10" M, 30-minute exposure; spindle fibers reduced by treatment but 

 chromosomes not dispersed. C. Concentration of, 2.5x10"" M, 90 minutes; star meta- 

 phase with some spindle activity. D. Clear spherical area, which is not stained, is the 

 hyaline globule, that increases when spindle substance disappears as a result of treat- 

 ment with colchicine. E. Chromosomes outside the star, 120 minutes, with 2.5x10' M 

 concentration. F. Multiple stars, three in one cell, 2.5 x 10" M, 180 minutes. G. Exploded 

 c-metaphase derived from prometaphase treatment, 2.5 x 10~" M, 15 minutes. H. Chromo- 

 somes shortened after 180 minutes, 2.5x10'' M, settle to bottom of cell. (Photographs 

 provided through courtesy of Drs. M. Gaulden and J. Carlson. Adapted from Experi- 

 mental Cell Research 2:416-33, 1951.) 



