STRUCTURE OF THE CHROMOSOMES IN THE SALIVAR GLAND CELLS IN SCIARA (DIPTERA)

Abstract

A study of the effects of acetic acid, osmic acid, formalin, mercuric chloride, and of hypo- and hypertonic salt solutions on the salivary gland chromosomes of larvae of S. coprophila and S. ocellaris. The appearance and disappearance of segments in the chromosomes following use of experimental fluids is attributed to changes in indices of refraction of the chromatic and achromatic portions as they are variously hydrated and dehydrated, and not to separation or fusion of the chromatic segments. The number and size of the vesicles appearing during fixation in both chromatic and achromatic segments depend in part on the nature and method of application of the coagulant. The finer details of structure seen in the segments of aceto-carmine preparations appear to be artifacts.