CYTOGENETIC ANALYSIS 481 



drying. It would be of great interest to follow this procedure, using only warm acetic 

 acid to check the role which lactic acid may play in the control of precipitation. 



The addition of 1 per cent lactic acid (by volume) to acetocarmine has enabled 



Fig. 63. A DIPLOID, FEMALE, ADULT, FIBROBLAST DERIVATIVE (FAF 28) WITH CYCLES OF 

 CELLULAR DIVISION OF 14 HOURS OR LESS. 



+ 



«.- 







y ft* 



Note the duality of the paired X chromosome ; the "predominant AV' and the "re- 

 tarded A 2 " are different morphologically and physiologically. 1500 X approximately. 



numerous plant cytologists to intensify the staining of pachytene chromosomes of 

 Zea mays, without unnecessary distracting cytoplasmic staining. 



When clones attached to petri dishes are to be stained, the medium is rinsed 



